Some Interesting Ideas From the Other Side of the Pond

I don't have time to go into detail at the moment, but I wanted to relay an interesting paper that Keith Cowing reported on NASAWatch today. Now, if I were someone at the ESA, I'd probably be taking NASA's grand plans about Constellation with an appropriate sized grain of salt right about now. But there were some good ideas overall:

• The report mentioned that our ISS experience shows the importance of having redundant transportation methods (ie imagine what would've happened to ISS if Soyuz didn't exist). I don't think that redundant transportation method should necessarily be another government-centric transportation system, but I agree wholeheartedly that monocultures are a bad idea.
• The report also mentioned that having a safe-haven in LLO is one of the best ways to increase the safety and flexibility of a lunar exploration program. Right now, most of the danger associated with lunar exploration have to do with operations on or near the moon. The current architecture does nothing to reduce those risks, but instead focuses on the much sexier earth-to-orbit transportation risks. Having some infrastructure in LLO can go a long way to fixing that, while also giving you some very interesting mission options. Now, I'm still a fan of the idea of Lagrange stations, and I think that in the long-run they'll dominate the traffic in the lunar half of cislunar space. I just think that there is a small, and critical niche filled by one or more small polar LLO stations. I've been planning to write up my ideas on this concept for over two months now, so can someone poke me in a few weeks if I haven't followed up on this thought?
• Unlike NASA they don't seem to be deathly afraid of on-orbit assembly when it makes sense. Of course, they don't have an HLV fetish that they have to rationalize...
  

There were a few other good points, but those three were the key ones that stood out to me. Of course they also seem to be missing the importance of propellant transfer, and they seem to be almost as clueless as NASA as far as commercial enterprise is concerned (both why it's important, and how best to foster real commercial involvment). But it was an interesting read if you have a few minutes.

Westward Ho?

Other than a busy schedule at work over the past several weeks, and ongoing blogger's cramp, one of the other big reasons why I haven't been blogging very much lately is that Tiff and I started reading together again. This is an old tradition of ours that we started back when we were poor newlyweds and couldn't find a cheaper date than borrowing a book for free from the library, snuggling up, and reading to each other. Anyhow, when we finished the Harry Potter series a few months back, I had decided I needed a break from reading together every night, so I could get caught up on my blogging. I still have another one or two installments to write in my Orbital Access Methodologies series. Seeing as how that hasn't really been happening, we decided to finish up the last two books in a nine-book historical fiction series we had started back in Santa Clara. To my surprise, reading this series has actually got me thinking more about space development, and so I figured I'd share some of my thoughts.

The series, The Work and The Glory, is a historical fiction adaptation of LDS Church history over the 1828-1847 timeframe, revolving around the lives of a fictional family, the Steeds. While the books do tend to get somewhat preachy at times, and while someone familiar with LDS history might find some of the foreshadowing to be a little weak, the series was overall a good read.

The Mormon Exodus
It was the last two books in the series that got me thinking about the challenges of space settlement. These two books, which we finished a few days ago, cover the Mormon exodus to Utah in 1846-47. In 1845, the deteriorating relationship between the Saints in Nauvoo, Illinois and their non-LDS neighbors got bad enough that the Saints agreed to leave the state by the end of the following Spring. Since none of the other states in the Union at the time were willing to accept the Mormon refugees, Brigham Young and other church leaders decided to colonize the Great Basin in the heart of the Rocky Mountains (which at the time were part of Mexican territory). The theory being that the area was pretty much unpopulated, nowhere near as nice as Oregon and California, and therefore they might finally be left alone.

What the story really brought out was how amazingly challenging of an undertaking the exodus was. The goal was to move all 15,000 Saints (many of them destitute) over 1200 miles through unsettled wilderness, and set up civilization in the previously unpopulated mountain valley around the Great Salt Lake. Much like space, the destination was not existing towns or settlements, and relative to other areas being colonized at the time, the area was very forbidding and unfriendly to human habitation.

One of the interesting points I gleaned from the story was the importance of infrastructure in making it possible to move that many people, and Brigham's use of advanced teams to help prepare the way for the main body of settlers. The original plan in late 1845 and early 1846, was that a set of advanced companies would lead-out, with the goal of reaching the Valley early enough that summer/fall to plant some quick-growing crops. The hope was that they could get there early enough to provide food for the main body of the Saints to survive the winter by the time they would arrive. Also along the way, they'd be blazing the trail: creating fords, digging down steep river banks to allow for easier crossing, building bridges or ferries where necessary. As the nasty weather that Spring in Iowa Territory bogged the Saints down, these advanced parties were instructed to build temporary settlements at several locations including Mount Pisgah, Garden Grove, and eventually Council Bluffs and Winter Quarters (near modern-day Omaha, Nebraska). They fenced in and cleared farm land, planted and cultivated crops, and then moved on, leaving those crops to be harvested by those who were still coming up the trail.

One of the other major lessons I learned was that settlement by large groups is inherently more complicated than settlement by smaller, individual groups. Especially when you need to move not only the rich and well-equipped, but also the penniless, starving, and destitute. In the end, by the end of 1847, only about 10-15% of the Saints had arrived in Utah. Things ended up taking well over twice as long in the end, but created an infrastructure that allowed everyone, no matter how poor to make the trip. Of the ~60,000 people who made the trip before the railroads reached Utah, many of those literally pulled pulled their way to Utah using handcarts. Without the ferries, resupply settlements, trails, rescue parties, the Perpetual Emigration Fund, and other pieces of infrastructure set in place during the initial exodus, many of those who followed would have never made it. Also, the experience gained in setting up the infrastructure for the exodus provided experience that eventually led to over 500 settlements throughout the Rocky Mountains (spanning from Mexico to Canada), playing a pivotal role in the settlement of the Western United States.

Anyhow, there are far more interesting stories (the Mormon Battalion, the Brooklyn Saints, the Donner-Reed Party, etc) that were covered in those two books than I can do justice too. So, if you can stomach the thinly-disguised religious apologetics long enough, I'd highly recommending digging into some of these books.

Important Differences (ie history never really repeats itself even if it rhymes)

While there are many possible similarities between the Mormon settlement of Utah, and the challenge of space settlement in our century, there are also lots of important differences. One of the keys to successfully learning from analogies is recognizing where they break, and understanding how those differences impact your situation. Because, as one of my history professors at BYU pointed out "all analogies fail at some point." Failing to recognize the differences between your analogy and real life leads to the sort of silly debates all too common in the space community.

Some of these differences make space settlement more challenging, while others might make it somewhat easier than the colonization of Utah that we've been discussing.

• At the time of the exodus, the basic technology for traveling directly to the Great Basin existed. Conestoga wagons, draft animals, firearms, ferries, sailing ships, bridges, etc were all technology that was already in use for commercial and military logistics purposes, as well as playing a big role in the settlement in the MidWest and other places. Much of the technology had been around for centuries or millennia. Not only were the technologies well-understood, but they were commercial available, cost-effective, and off-the-shelf. While there were still improvements being made continuously, as far as settlement was concerned, the commercial state-of-practice for ground transportation at the time was far beyond what the commercial state-of-practice is for space transportation today. A particular case in point is the wagons.
  
• Along the trail and at their destination, the Mormon colonists were frequently surrounded by ready sources of food, “fuel”, water, and raw materials for repairs. While it was still possible to starve and die or to run out of water, or to break down in an area where there wasn't readily available wood (just ask the Donners and Reeds), the general availability of easily extracted in-situ resources was much better for the pioneers than it will be for future space settlers. After all, even the air isn't free in space. Sure, there are potentially interesting ISRU technologies out there, but they're nowhere near as mature as cutting wood, shooting buffaloes, carrying water in barrels or canteens, or simply allowing the cattle to graze along the way. Not to mention the fact that you didn't have to carry all the food for your animals for the whole first half of the Mormon trail...
• While they weren't as common as would've been nice, there were several human settlements in existence along the way by that point. Places like Fort Laramie, Fort Bridger, and Independence, Missouri. While goods were expensive, they did allow for restocking at some price of hard-to-replace items.
  
• Transportation physics were completely different. While I don't think that the rocket equation makes inexpensive space travel impossible, it really complicates things, and sure doesn't make it easy. Combine that with the lack of stopping places between here and LEO, and the transportation physics are much less favorable for space settlement.
• On the side of things that are easier with space settlement, the Moon is a much shorter trip than the trip from Nauvoo to Salt Lake City. The fact that you're talking about less than a week worth of travel instead of several months makes a huge difference in some of the required provisions and supplies.
• Modern water and air recycling technologies, when combined with freeze-drying can allow for a much smaller amount of food mass per person per given amount of time--potentially over an order of magnitude less.

The Big picture
Basically when you look at where we are today relative to space settlement, we’re nowhere even close to settling the solar system (not even the moon) as the Saints were to colonizing Utah when they were camped at Sugar Creek, across the river from Nauvoo in the bitter winter of 1846. Our civilization as a whole has never even flown 100 people to orbit in a year, let alone 1000, 3000, or 5000.

Just to give a sense of the scale we're talking about, here are some rough numbers to think about. Suppose it takes at least 6000-7500lb per person (which is probably a very optimistic bare minimum) to settle and survive off-planet. If those numbers are accurate, then in order to settle 15,000 people in space, even just in LEO, you’re talking somewhere around 45,000 tons of material needing to be lifted. Doing that over a 3-5 year period like the first wave of the Mormon Exodus would require 9-15 thousand tons to be lifted to orbit every year. That’s over 100 Ares-V equivalents per year, and several orders of magnitude higher than what has ever been done before. And that’s assuming that they all stop in LEO! Going to the moon would require something like 6-10 times that mass in LEO in order to do that, and Mars or Venus would likely require even more. That gets you to 90-150 thousand tons per year!

At least right now, if some group of 15,000 people were given a similar ultimatum to what the Saints got in 1845, they'd probably be screwed.

ISRU, Infrastructure, and Access
Now, in this article, I'm not going to go into the rationales that could potentially justify settlement on that scale, or even if it is desirable at this point in time, or how soon it would be desirable. I'm just trying to paint a picture of the kind of things that would need to happen in order to make such an exodus feasible in the first place. Think of this section as a sort of roadmap for stuff that would need to happen between now and when space settlement becomes an even remotely realistic possibility.

With that in minde, once you start to realize how mind-bogglingly large the numbers are when you start talking about serious space settlement, you realize that if such a state even is reachable, it will require attacking the problem from multiple directions. There are three different primary areas of development necessary for enabling space settlement: space access, in-situ resource utilization, and in-space transportation technologies and infrastructure.

Even though lower cost, reliable, and very frequent space access is probably the most important step in the near-term (and also the one that has the clearest near-term potential for ROI and thus commercial feasibility), I want to start by talking about ISRU. ISRU helps enable space settlement by reducing the amount of mass you need to ship to orbit in order for someone to settle somewhere in space. Using the historical analogy I started in this post, colonizing Utah would've been far more difficult if all the food, draft animal feed, and construction materials for Salt Lake City had to be hauled from Illinois. In fact, if that were the situation, colonization would've been impossible. ISRU basically allows you to hack the space access (ie earth-to-orbit) transportation problem back down to a size that might be workable.

ISRU covers a wide variety of areas including in-situ propellant production, production of life support gasses and liquids, production of construction materials, farming, and eventually extracting and processing industrial raw materials, and manufacturing finished goods. Many people in many venues have talked about this subject (particularly Peter Kokh in his "Moon Miners Manifesto" newsletter), but I want to put my own spin on it. For enabling settlement, there are some ISRU areas that are higher leverage than others (ie where you get more of a payoff for a smaller initial investment). As I see it, the two highest leverage areas for enabling space settlement are in-situ propellant production and in-situ construction and construction materials extraction/processing. Of the mass you need to take to LEO in order to settle on the Moon, Mars, the upper Venutian atmosphere, or even the asteroids, most of it is going to be propellant for the trip. Eventually, as more advanced in-space transportation technologies get fielded, this may change, but if space settlement occurs in the near to medium future, I think the importance of oxygen and hydrogen (and possibly some light hydrocarbons like methane or propane) is major. The next biggest mass is going to be the actual structures that people live in and the other buildings, roads, etc. In fact, some previous studies have pointed out that if you can use ISRU to provide for spacious extra-terrestrial facilities, it can have spillover effects on lots of other things. If your internal space is relatively spacious, for instance, you might be able to have more of the work you need to do be done inside, in a shirtsleeve environment, thus allowing you to more directly leverage existing terrestrial tools and processes, without having to do as much redesign.

When you look at in-situ propellant production, something you realize very quickly is that the less you have to ship propellants around, the better. In other words, the closer you can harvest propellants to the place they will be used, the better. That's one of the reasons why even though it's a long-shot, I'm so interested in the whole concept of atmospheric propellant gathering. LEO may be halfway to anywhere, but it's also halfway from anywhere too. If you can gather LOX in-situ in LEO, and especially if you can do it in large quantities at reasonable cost, that would have a major impact on the cost of beyond-LEO transportation. On the other hand, another thing you realize when you study the problem is that due to the rocket equation, propellant resupply on the final legs of the trip have a disproportionately large impact on the overall propellant requirements. Being able to ship a Lunar, Martian, or Venutian lander "dry" saves a lot more weight to LEO than just that landing propellant. It also save the propellant needed to ship that propellant to the destination in the first place. So, at least to me, the two highest payoff places for propellant ISRU are in LEO (if possible) and in orbit around the final destination (for planetary destinations).

Other forms of ISRU such as farming, large-scale manufacturing, extraction and processing of industrial metals, etc. all have an impact on the situation, but for the most part they are much lower leverage--as far as space settlement itself is concerned. We might still see some of the metals extraction and processing sooner rather than later if for instance, it turns out that Dennis Wingo's theories about lunar PGMs turns out to be true. But as far as actually getting there and setting up shop, propellant extraction, and extraction of the simplest construction materials is more valuable.

In order to use those ISRU derived propellants, you need more matured in-space transportation technologies and infrastructure. You need propellant depots, you need reusable in-space transportation (as well as reusable landers). You need technologies that make reuse easier such as better aerobraking (which may involve both infrastructure like satellites, and space technology like better reusable TPS, ballutes, etc). You eventually need infrastructure to service and maintain those transportation systems. You'll probably want lots of prox-ops tugs, and you'll eventually want rescue services (possibly provided by some of the prox-ops tugs). Some of this infrastructure wants to be in LEO (in whatever inclinations have enough demand and/or cheap supply to make sense--and probably eventually multiple smaller depots in the same inclination), and some of it in the vicinity of the destination (for the moon this could mean elements in L1, L2, and/or low lunar orbit, for Mars this probably implies stuff in Mars orbit, or possibly on Phobos or Deimos themselves, for Venus you'd be talking about a Venutian orbit). This infrastructure will probably grow "organically" as market and governmental demand for those services grow. It's hard to know in advance what exact mix of propellants, inclinations, number and size of depots, etc will make the most sense--so it will need to be market driven (and yes, government customers are a market too--just a potentially very dysfunctional one that needs to be treated with a lot of care).

The core reality though is that in order to be able to even get to the point where large infrastructure or ISRU development can really take off, the space access (ie earth-to-orbit) transportation situation needs to improve. Even if you're getting all of your TLI and landing propellants from lunar and upper atmospheric sources, you still need to be able to ship vast amounts of material up from earth, and in order for settlement to be feasible it has to be both significantly cheaper than current launch methods allow, but also the sheer quantity of material that needs to be shipped (even with the rosiest of ISRU scenarios) requires a fundamentally different approach to space transportation. While you may be able to do some of the early infrastructure development with existing launch vehicles (tugs and early "pilot-plant" scale propellant depots come to mind), largescale infrastructure and most ISRU other than atmospheric propellant gathering really need lower cost and more frequent transportation.

As Henry Spencer has put on multiple occasions, developing and debugging ISRU on the moon is going to be an involved process, even if it may be a very worthwhile one. The idea that we're going to design a working ISRU plant, ship it out to the moon, set it up with a few robots, and then start pumping out LOX right away is ludicrous. We know some things about the moon, and there are some good ideas on how to solve some of the more pressing problems, but the reality is that the lunar environment cannot be simulated 100% here on earth, and there are going to be plenty of snags, complications, and unexpected events. Developing hardware, materials, design processes, chemical processes, etc that can cope with the local environment is going to require trial and error and probably several people "on the ground". It's going to take time and lots of work to develop spacesuit materials that can handle the dust, making seals and airlocks that do what we want them to do isn't likely going to be one of those things we get right the first time. And especially once you get into things like metals extraction and processing, developing construction techniques, etc. you see more of the same challenges. And the reality is that the same thing probably applies for Mars, or Venus, or the Asteroids, or even to living in orbit or in deep space. In theory there's no difference between theory and practice, but in practice there always is.

Improvements in space access need to not only include cost, but frequency, reliability and sheer volume. When you look at the air transportation industry, you're probably talking about over 10,000 jets flying every day (some of them multiple times per day) from hundreds or maybe even thousands of airfields. With rocketry today we have something like two dozen flights per year from about one dozen or less active sites. If we're going to get to the point where we're shipping hundreds or thousands of people and their goods to orbit there are things that fundamentally need to change. One of the biggest changes isn't just going to reusability, but going to reusable vehicles that can fly from many locations. While what SpaceX is trying to do is technical reusable (or at least recoverable), they're never going to be able to operate out of more than three or four launch sites (Kwaj, Vandenburg, Canaveral, and maybe Wallops). Same applies for some of the reusability ideas I've seen bandied about by other ELV groups. Sure, for larger goods, those types of reusability are an incremental step in the right direction. But in order to get from where we are now to a transportation system that can fly 1000s of people and their goods to orbit every year, ELVs or recoverable ELVs really stop making sense at some point.

In order to get to the point where we could fly that many people and their stuff to orbit every year, not only do you need "reusable" launch vehicles, but they also need to be capable of high flight rates, capable of operating out of many launch sites (including combination airport/spaceports like Mojave), and safe and reliable enough that they can launch at least some of the time over land. In Part I of my Orbital Access Methodologies series, I discussed one such potential approach, in the next part(s) I'll be discussing a few more.

Summary
Getting to a point as a civilization that we're truly ready to start spreading out throughout the solar system is going to be a difficult process. We're nowhere even close to where we need to be, and most of the options being investigated by national governments are pretty much orthogonal to where we need to go if we want to see our civilization become a truly spacefaring one. Getting to there from here will require work on radically improving earth-to-orbit space access, developing in-space transportation technologies and infrastructure, and learning how to tap the resources of the upper atmosphere, the Moon, and other planetary and asteroidal bodies. There is useful work that can be done now on all three of these areas, but we've got a long way to go, and the engineering challenges are very interconnected. Probably the biggest challenge of all is going to be finding a way to craft solid and profitable business cases along the way to fielding these technologies.

Westward Ho? We'll see, but we probably have an even rockier road between us and our destination than the Mormon pioneers did in the spring of 1846.

Monte Davis on ISS and Microgravity Science

[Note: As a bit of a preface to this repost from a usenet group, I wanted to give a bit of background. I first got interested in the whole commercial space thing when I was 16, mostly through a usenet group I had stumbled on called sci.space.policy. Unfortunately, as time went on, the group's signal to noise ratio got worse and worse. Things were still survivable when I got back from my mission in 2002, but have slid rapidly since then, with most of the old regulars having moved on. I haven't given up 100% on usenet, but due to the awful S/N ratio, I'll typically just google to see if certain specific individuals have posted anything interesting lately. With Henry Spencer gone, I'm down to just a handful of people on there whose posts I look for (Monte Davis, Jorge Frank, and Derek Lyons). Every once in a while, I'll stumble across a gem that reminds me why I haven't completely turned my back on usenet, such as this one from Monte Davis a few days ago]

There's been a lot of discussion, particularly at Space Cynics about ISS, its suitability for microgravity science, and the utility of microgravity research and development in general. Today, most people who have been following the program agree that the ISS has been a bit of a debacle, and most agree that the way ISS is run and the existing space transportation situation pretty much preclude any real commercially useful microgravity research from happening. However, Monte makes some useful points about the situation that while I've made similar points in the past, bear reemphasis. Here are Monte's comments (with my emphasis):

(Derek Lyons) wrote:
>Which, in my book, makes the person who thinks that's a condemnation
>of the Shuttle... an idiot. Because that was the goal of the Shuttle
>from Day One, to work with a space station.

The seemingly neat circularity emerged after the fact. With cheaper
and more frequent access, the station could have been built soon and
cheap enough, equipped and staffed adequately, to actually *do* the
kinds of research originally promised.

But with the successive delays and downscoping, that has never been
possible. Unfortunately, that has discredited the whole premise and we
get the "all we do is go around in circles in LEO" mindset, and a
vague sense that "they tried all that free-fall science and nothing
panned out" -- when in fact, all but a few token bits of science have
been squeezed out by the demands of just getting it "complete" before
the oldest parts reached the end of safe service life.

(NB: I'm not claiming the most hyped promises -- the giant protein
crystals, perfect ball bearings, breakthroughs in undersatnding
free-fall physiology etc -- would have paid off; I'm saying there's
never been a chance of finding out with the very limited equipment and
even more limited time available for them).

It's as if I'd tried to build a house on a mountaintop using a
Lamborghini to carry materials and workmen. Surprisingly, the house
ends up a lot more expensive, less spacious and well-equipped than I'd
hoped... and I conclude "well, that proves a house on a moiuntaintop
is a dumb idea."

While as Monte says, the fact that we haven't even really had a chance to try doesn't prove that microgravity research will ever produce real benefits, it does mean that there is a chance if things are done differently that we might get better results. There are plenty of challenges out there facing large-scale microgravity research and manufacturing, particularly due to the snail's pace of progress when compared to terrestrial approaches that try to eliminate the need for microgravity. But I think one of the hopeful things that could come from the latest wave of commercial space endeavors is an environment much better suited towards real research and development. Between suborbital microgravity services (from existing players like Up Aerospace, and hopefuls like XCOR, Armadillo, us at Masten, etc) in the nearer term to commercial stations and free-flyers like what Bigelow is trying to do, things are starting to move in a direction where the rapid iterations that good science needs can become possible.

That doesn't mean it will work, but it does mean that this time we'll actually get to find out one way or the other.

A Point Worth Repeating

Over on Jeff's SpacePolitics site, there is a discussion going on right now about a recent poll on the relevance of space. While much of the discussion was interesting as usual, I particularly liked the point made by a fellow 20-something by the name of James:

Those who support the current lunar program often forget the opportunity costs. There are better ways to spend the same money on developing space. I’m 24 - with the current Constellation program plan, I’ll be in my mid 30s by the time we get back to the moon. If we operate the system for a decade or two after that, as is likely, all I can expect in my career is to see 4 people land on the moon twice a year. That is not exciting - nor is it worth the money. Maybe by the time I retire we’ll be looking at another “next generation system”.

What’s the point of any of this for someone my age?

Two of the replies to his question more or less missed what I saw as the key point, and instead mostly fixated on the question at the end--taking it as a sign of greed, self-centeredness, shortsightedness, etc. Personally, I don't think for a second that James was being whiny or impatient or ADD (as our generation is often accused of). I think he's asking a very valid and timely question.

While I know it's somewhat vain to quote oneself, I think the point I made there bears repeating:

If our current approach to space development was actually putting in place the technology and infrastructure needed to make our civilization a spacefaring one, I’d be a lot more willing to support it. Wise investments in the future are a good thing, but NASA’s current approach is not a wise investment in the future. It’s aging hipsters trying to relive the glory days of their youth at my generation’s expense.

Patience is only a virtue when you’re headed in the right direction and doing the right thing. If Constellation was truly (as Marburger put it) making future operations cheaper, safer, and more capable, then I’d be all for patiently seeing it out.

While Constellation might possibly put some people on the moon, it won’t actually put us any closer to routine, affordable, and sustainable exploration and development. I have no problem with a long hard road, just so long as its the right one.

As I discussed in my previous post on John Marburger's speech, I discussed this important point. It's not good enough for NASA to just be doing stuff in space. Sending people to the Moon in a way that doesn't "reduce the cost or risk of future operations" isn't a very responsible way of spending tax dollars that are going to be paid in large part by James and my generation.

Additional Thoughts on the SA'08 Propellant Depot Panel

It's been long enough since I put up the presentations from the panel, that I figured it would be worth starting a new post to mention some of my thoughts on what we discussed on the panel. Some of these ideas are thoughts that were briefly discussed during the panel, and others are ideas I just didn't have time to bring up.

While the panel went much better than expected, I also noticed several things I could do next time to make it even better.

One thing is that I probably should have mixed audience participation, discussion, and presentation a little more thoroughly. Expecting people to stay awake through an hour of presentations right after dinner was a bit much--surprisingly enough most of the attendees did, but I think mixing it up would've been better.

Another thing that in hind-sight would've been useful is to set aside more time in the panel for actual discussion, particularly on points where one or more of us had a different preferred approach than the others. For the most part we all agreed on the importance of propellant depots, the benefits to commercial and governmental programs, and the fact that a lot of the technology either exists, or is on the cusp of existing. But we disagreed on some of the details, and much like statistics, it's the disagreement or outliers (and the reasoning behind them) that hold the most information.

Tugs or Reusable Tankers or Both

One point of disagreement was between myself and Dallas Bienhoff regarding the best way for handling prox-ops for propellant deliveries. I am a big proponent of using space tugs to offload as much of the weight and complexity of a prox-ops system to an asset that stays on-orbit and gets used a bunch of times. Dallas on the other hand disagreed with me on that point and suggested that a reusable tanker with autonomous rendezvous and docking capabilities was a better way to handle complexity and reduce cost. Both of us were advocating for reusing as much of the complicated prox-ops hardware as possible, but going about it in different ways.

To me, there are several benefit of having the tanks dumb as possible, with all of the complicated subsystems on the tug:

• Performance: the tug stays in orbit, and is very weight insensitive. By not having to relaunch the tug every time, you get a lot more propellant per pound of delivered mass on orbit. When you look at unmanned delivery craft right now, they typically have a really poor payload to drymass ratio. For a tug you want as high of a payload to drymass ratio as possible.
• Easier Open Interface Standards: It is probably a lot easier to get ITAR approval for openly publishing a very simple common interface specification if that interface spec is just a few handholds and a commercial, off-the-shelf quick-disconnect receptacle. That way, anyone who can launch stuff into your station's orbit can deliver propellants to your station, even if they're durned furiners. An Autonomous Rendezvous & Docking (AR&D) system with automatic fluid couplings would likely be a lot harder to get export approval for.
• Flexibility: The simpler the propellant module, and the less smarts it has built-in, the easier it is for people to just stretch it to whatever size best suits their launch vehicle. Unlike a reusable tanker which might require significant redesign to be used on a different launch vehicle.
  
• RLV Simplicity: Making a high-flight rate reusable launch vehicle is going to be hard enough already without trying to also make it into a satellite as well. For RLVs, you want a relatively dumb tank that never leaves the payload bay, but you don't want to have to have all the prox-ops stuff cut into your already very limited payload budget.
• Other Tug Uses--On-Orbit Assembly: Tugs are useful for lots of other things too, especially if they have arms. They can help in assembly of stations and large in-space vehicles. No need to make each and every space station or space vehicle component be its own independently operable mini-station complete with its own GN&C, power, etc.
  
• Other Tug Uses--Satellite Recovery: They can also perform satellite recovery missions. Imagine if there had been a tug already developed, and set aside on standby in case of a botched launch like the recent Proton upper stage failure. If done properly, the tug could've been launched on short notice on an otherwise empty upper stage. The tug could've then transfered the satellite from the malfunctioning upper stage to the still functional, and mostly full upper stage that delivered the tug. There are some very tricky technical details I'm glossing over, but its a capability that could become rather standard once you have tugs available. In case anyone from the DoD is reading this, yes, I'm saying that tugs are an important part of ORS.
• Other Tug Uses--Rescue Missions: They can perform rescue missions. Right now, one of the most hazardous parts of a lunar mission is the ascent, rendezvous, and earth return legs. Imagine if there was a staging point in L1, L2, or LUNO, instead of basing all lunar missions from earth's surface. You could store one or two of these tugs at the small staging/refueling base. If something went wrong with the LSAM US or CEV, you could send a tug in to help out. If you were using lunar ejector seats, and had to abort to orbit, this would give you a quick way of getting a rescuer to a stranded astronaut. This would greatly reduce your odds of losing a crew due to a LSAM/CEV rendezvous failure, or CEV propulsion failure prior to (or during) TEI.

And there are probably other ideas I'm overlooking.

On the other hand, Dallas a good point in favor of reusable propellant tankers, and I can think of some others as well:

• The more expensive propellant handling hardware your tanker needs, the better it would be to reuse it. For instance, say you don't think you can get first-orbit or even first-day rendezvous with your propellant depot. You might want to invest more heavily in insulation, zero boil-off systems, and other cryo handling hardware. You don't want to be tossing that away after every flight.
• You're eventually going to want to have smaller depots located on the other ends of your transportation system (ie in the lunar vacinity, around Mars, around Venus, etc). Some of these locations, especially at first, will need to be fueled from Earth. That means tanker modules are necessary. Once again, once the flight duration gets longer than a couple of hours, you're going to start wanting to add other bells and whistles. And those bells and whistles are expensive enough that not throwing them away after every flight is a good idea.

Dallas may have had some other points that I'm not remembering right now, but I think that both sides have valid points, and that the best option may be to do a little bit of both.

Full-Service vs. LOX-Only?

I had been somewhat surprised when Dallas (who works for the company that was the lead on developing and flying Orbital Express) suggested against using a tug. I was even more surprised when Frank Zegler suggested a LOX-only depot. Before I had met Frank over the internet, I considered LH2 to be an unmitigated evil, almost on the level of Nitrogen Tetroxide and UDMH. But he was one of the main people to talk me into thinking that Hydrogen isn't always evil, and sometimes can be tamed, and can make a lot of sense. So, when he sided with the sentiment that meiza and several other regulars here at Selenianboondocks have expressed--namely that your first depot should probably be LOX only--I was very surprised.

I didn't have time to bring up this point of disagreement at all during the panel, but here were some of Frank's points in favor of LOX-only depots:

• LOX is much easier to store and handle cryogenically due to its much higher boiling point.
• LOX is much denser, and thus you can store a lot more of it in a given size tank.
• LOX makes up the majority of the propellant mass than for any fuel combo you would likely use.
• Storing only one liquid is much easier than two, because you can eliminate the heat transfer from the warmer propellant (LOX) into the colder one (LH2). Even with a sunshield or a ton of MLI, you still have a significant heat source in the fact that your LOX is way hotter than the boiling temperature of your LH2. You probably never thought of LOX as a heat source, did you?

If these arguments sound familiar, its because they're the same ones that many of you have made over the years. I can see Frank's point, especially if you think that your main (or only) market is going to be "topping up" EDSes and LSAMs for NASA. I've never disputed these facts. But I still think that going all the way and providing at least one fuel to go with that LOX is a good step. These arguments probably aren't new, and probably aren't going to change anyone's minds, but in case you haven't heard my spiel before here's my case:

• Without modifying existing or future stages, they only have so much hydrogen capacity. Unless you launch a complete stage as your payload, topped-off to the brim, you're going to use some of that capacity getting to orbit in the first place. Which quickly cuts into your maximum payload you can deliver to your final destination (and also how much LOX you can actually use).
• For many payloads, prior to the time when reusable LEO-GEO or LEO-Luna ferries are available, the best way to use a propellant depot is to launch the payload on a refuelable upper stage, top that upper stage up in LEO, and then immediately go to your destination. If you reuse your upper stage as your transfer stage, the inability to top of the hydrogen as well effectively halves your payload you can deliver to other destinations. If you fly a separate refuelable stage that has a full load of LH2, you're greatly cutting into how big of a payload you can put into LEO in the first place. For instance, a Centaur stage with a full load of LH2 weighs about half of the payload capacity of an Atlas V 401 to LEO.
• If you can't provide both oxidizer and fuel, you can't reuse interorbital transfer stages/ferries.
  
• If you can't provide both oxidizer and fuel, you can't reuse lunar landers.
  
• If you can't provide fuel on-orbit, you can't make up for boil-off caused by unexpected delays, variance in the thermal properties and boil-off rate of your stages, equipment malfunctions etc.
• On a psychological level, going LOX-only allows people to continue to disbelieve in the feasibility and utility of propellant depots. Look at the mindset two years ago. It said that propellant transfer of any sort on orbit was deep, black magic, and that it should be avoided at all cost. Now that Orbital Express has shown that it is doable and not that hard for storable propellants, critics say "well, that's all good and fine, but cryogenic propellants are a whole different beast entirely." If we went to LOX-only depots, those same critics would likely say "well we knew LOX was doable all along, it's the hydrogen that's the unrealistic part--there's no way you could store that long enough to be practical." At some point I want to stop giving skeptics ammunition.
• More importantly, both Dallas and Frank agree that LH2 storage on-orbit is completely feasible. Dallas going so far as to say that for 1-2kW and 50-60kg, you could install a ZBO system that could completely eliminate boil-off.

I guess I'm still convinced that in spite of the added extra difficulty, that the real markets that I think there will be for propellants on-orbit will be much better served if you can provide fuel as well as oxidizer. But you can draw your own conclusions.

To ZBO or Not to ZBO?

Another disagreement (this time between Dallas and Frank) was on whether or not to go with a Zero Boil-Off system for long-duration cryo storage. Dallas seemed to think that not only would it not be that hard to implement, but that it would be very desirable, while Frank seemed to prefer passive storage techniques, and in fact considered ZBO to actually be a detriment! I think both sides have points, but that in a way they're somewhat talking past each other. And in the end, I think I side more with Dallas on this one.

Frank is right that ZBO systems, done the typical way, (without doing a proper passive-storage design and without settling propellants) is likely going to be an expensive development project, and a complicated system in operations. Frank also made the point that at least some of the boiled-off hydrogen is actually useful. That warm GH2 can be propulsively vented to cause the other propellants to stay in a settled orientation. It is still pretty cold, so it can be used to pull heat from the avionics away from the propellants. It can be used for prechilling lines and valves. It can be used to provide propellants for GOX/GH2 RCS engines. It can be combined with oxygen in a fuel cell to provide water. The single most important benefit for Frank and ULA is that first one--settling the propellants makes everything easier, and propulsive settling is by far the highest maturity and easiest way of settling propellants.

As Dallas pointed out, a properly designed ZBO system when added on-top of a good passive insulation system doesn't need to be that big and complex. 1-2kW isn't that much power. And especially if the propellant is settled in some fashion, running a cryocooler becomes even easier, because you can avoid two-phase flow. If your cryocooler works better taking gas in and spitting out liquid (or chilled gas), settling allows you to guarantee you're only pulling in gas. If pulling in liquid, subcooling it, and spraying it through the gas is more effective, settling allows you to pull liquid from a part of the tank where you know liquid will be, and to inject it into a part of the tank where you know it will be gas.

Lastly, there are other ways to settle propellants, and if you use them, you no longer need boil-off gases to provide the settling. You might still intentionally allow some LH2 to boil-off, for use in RCS engines for stationkeeping or to run fuel cells. But with a ZBO system, you have a choice.

A more convincing argument against the complexity of a ZBO system, that can be derived from Frank's presentation, is the fact that a good passive system can get boiloff rates low enough that you just don't care about them anymore. In those cases, a ZBO system might not buy you that much extra performance. Now, there's an argument against ZBO that I'm more willing to buy.

So, I guess the real answer may be--it depends. In situations where your propellant is expensive enough to deliver to, where deliveries are somewhat infrequent, and storage times are long, a ZBO system might make a lot of sense. But in situations where the propellant can be readily topped off from tankers on a regular basis, even though ZBO is doable and not that hard, it still might not be worth it.

Once again, draw your own conclusions.

NASA vs Other Markets

This last topic isn't so much a disagreement, as an area that I thought deserved a little more commentary. I think that all of the panelists would agree that NASA is unlikely to have a change of heart tomorrow, and completely overhaul Constellation to take more advantage of propellant depots. However, in spite of this recognition that NASA isn't likely to become a good customer anytime soon, most of the panel was still very NASA- and Constellation-centric. While there were mentions made by all the panelists about performance benefits that normal ELVs could get for delivering payloads to GEO and beyond, most of the discussion of benefits was focused on augmenting NASA's return to the Moon.

Admittedly, if NASA ever gets its act together and actually makes it back to the Moon, it will be annually consuming more propellant mass in orbit than the combined launch mass of all other launches combined, and if they were actually buying that from propellant depots, it would be a truly transformational event. But lets face it guys--it makes too much sense for NASA to willingly go along with it. Much like Zero-G demonstrated, while NASA might eventually be willing to abide by the law and purchase commercial services that they used to provide for themselves in-house, it will take many years to get them to change. As it is, it'll take NASA a decent amount of time before they can even take advantage of depots, even if they recognized the potential right away.

As I said in my presentation, it doesn't matter how critical propellant depots are for creating a spacefaring society, or how much better lunar exploration would be with propellant depots involved. If you can't find a way to get enough real customers to wrap a business case around, it will never happen.

That said, I also wanted to note that NASA and the DoD are actually doing some good things regarding propellant depots. First, they've regularly put out SBIR solicitations for technologies that could be relevant to propellant depots. Second, on the larger scale, they've funded actual technology demonstration missions like Orbital Express, DART, and XSS-11 to demonstrate useful related technologies. Third, even though Michael Griffin's NASA hasn't been doing much action-wise to enable propellant depots, Griffin has at least been a vocal proponent of the capability in many public forums. Fourth, NASA was at least interested in offering a propellant depot related Centennial Challenge--if they had actually been given any new Centennial Challenges funding in the past three years.

Even though I don't think either the DoD or NASA is likely to outright fund a propellant depot anytime soon (and personally I wouldn't want them to!), there are lots of things that can be done within the system to help move things closer to reality. Better, clearer ties can be made between the technologies needed for propellant depots, and the needs and desires of NASA and the DoD. Tugs and depots, for instance, are an important part of a truly Operationally Responsive space transportation infrastructure. By making that connection more and more in public, additional funding for research, development, and demonstration might become available. NASA also desperately needs good long-duration cryo storage and handling technologies in order to make ESAS work, and at least some of those technologies will also be useful for propellant depots. Propellant depots (especially commercial ones) might allow NASA to launch larger interplanetary missions than would otherwise be possible, etc. So while I think the key to propellant depots lies in markets outside of NASA, I think there's a lot of good NASA and the DoD can still due, even in spite of the political environment and constraints that both of them operate in.


Anyhow, those were some of my thoughts I wanted to discuss from the panel. Once I get the video from Henry, I might find a couple changes or additional comments to bring up, but for now those are my thoughts.

Comments?

[Update: 4/4 8:30AM PDT]
Here is the link to a thread on NASASpaceFlight.com where I have been discussing propellant depots with some of the other regulars.

Propellant Depot Panel Questions

I'd like to solicit questions regarding the technical or business aspects of orbital propellant depots for the panel I'll be chairing this coming Friday. I've got a great lineup of panelists (Rand Simberg of TransTerrestrial Musings, Dallas Bienhoff of Boeing, and Frank Zegler of ULA), so if you have any good questions about propellant depots, just post a comment here, and I'll try and pick the best two or three to start off the Q&A part of the panel discussion.

Sustainability

A statement in this post by Clark Lindsey (and a further comment by Gary Hudson) on Hobbyspace reminded me why I'm somewhat uncomfortable with the term "sustainability" as it regards space exploration. I think the danger stems from how ambiguous the term can be. When you say "sustainable space development" to someone like Clark, Gary, or myself, it evokes concepts such as enabling a robust commercial spaceflight industry and acting as an anchor tenant for critical space infrastructure. But NASA uses "sustainability" in a completely different light. Under Griffinomics, ESAS is supposedly "sustainable" because Congress is unlikely to cut NASA's manned spaceflight program much compared to what it's getting right now, and therefore even if the architecture they pick is very expensive, it can still be perpetuated indefinitely off of bureaucratic inertia and parochial interests. Inspiring, huh?

A much better metric is the one given in Marburger's speech: namely is our architecture being developed in such a way as to reduce the risk and cost of future operations? In manufacturing, there's a concept called "continual improvement". Basically the idea is that in a healthy system, you should be continually reducing scrap rate, increasing efficiency, decreasing lead time, etc. I think the idea of continual improvement is a good one for space development as well. A healthy and effective national space program would be one that is continually investing a sizable chunk of its public funds into creating or promoting the creation of new technologies, techniques, infrastructures, and markets that make future operations (manned and unmanned) less expensive, lower risk, higher payback etc.

To me the difference between the idea of continual improvement and Griffin's idea of sustainability is the difference between innovation and inertia.

Marburger's Speech

There's been a lot of discussion over the past few days about OSTP Director John Marburger's speech at the recent Goddard Memorial Symposium, but there were a couple of good points that I felt deserved repetition, and I also had a few thoughts I would like to add.

One of the memes that John started two years ago is the concept of extending our nation's economic sphere throughout the Solar System. Early on in his speech, referring to the thriving commercial satellite market, John states that "Humanity has succeeded in incorporating Low and Geostationary Earth orbit in its economic sphere." While I think he's basically right, I'd just point out that LEO and GEO are still only on the fringes of our economic sphere. While there are a couple of (very large and profitable) niches that have been exploited in spite of the immature state of existing earth-to-orbit transportation systems, none of these markets really have succeeded in catalyzing further demand for other services in LEO and GEO. While lots of money is being made, and lots of useful services are being provided, we still have a long way to go before I'd really state that LEO and GEO are firmly within mankind's "economic sphere".

The most important idea from this speech is found in the next paragraph:

If we are serious about this, then our objective must be more than a disconnected series of missions, each conducted at huge expense and risk, and none building a lasting infrastructure to reduce the expense and risk of future operations. If we are serious, we will build capability, not just on the ground but in space. And our objective must be to make the use of space for human purposes a routine function.

He amplified this point a few paragraphs later:

Exploration that is not in support of something else strikes me as somehow selfish and unsatisfying, and not consistent with the fact that we are using public funds for this enterprise, no matter how small a fraction of the total budget they may be.

If the architecture of the exploration phase is not crafted with sustainability in mind, we will look back on a century or more of huge expenditures with nothing more to show for them than a litter of ritual monuments scattered across the planets and their moons.

I think that though this may not have been his intention, these quotes highlight most of my current frustration with NASA's current approach to executing the Vision for Space Exploration. Having NASA develop its Constellation architecture means that 20 years from now, it will be just as hard for a commercial entity to get to the moon as it would be if Constellation was cancelled tomorrow. Nothing that is being done "reduces the risk or expense of future operations" or "makes the use of space for human purposes a routine function." I'm glad that at least someone is trying to tie this all back to actual benefit to the nation. I'm also glad that John pointed out that the whole "NASA only spends less than 1% of the federal budget" line does not give NASA carte blanche to spend that money however it darned well pleases. That money is supposed to be spent in a way that furthers the national interest, preferably in a way that makes space more accessible for everyone.

Now, NASA isn't completely neglecting its responsibility to help reduce the risk and expense of future commercial, defense, and NASA operations. They are doing such things as COTS and Centennial Challenges. And people in power seem to be finally wising-up to the idea that COTS is the only real hope for reducing the gap, and the only way to economically services the ISS once the Shuttle is finally retired. But I do think that it's a big negative mark that the vast majority of the money NASA will spend over the next decade on Constellation has nothing to do with making the moon easier for everyone to access in the future.

There's been talk from NASA and some of their less discerning fanboys of a "Lunar COTS". Basically the idea is to waste $100-120B on using Constellation to setup a small ISS on the Moon, and then once its there start paying commercial entities to service said base. This creates an interesting situation. Since NASA won't have done anything for over a decade to help make it easier for commercial entities to actually service the moon, they'll either have to keep sustaining the base themselves while they spend the money to belatedly help develop that commercial capability. Or, if the commercial market has independently created that capability anyhow, that NASA base will likely be only a small niche market in the cislunar space. The smart thing to do would be to start finding ways to develop or promote those commercial capabilities from the start. Things like funding research or sponsoring prizes for fielding the technologies needed for propellant depots. Acting as a customer for commercial services especially on-orbit propellants. Acting as a better customer for commercially attained lunar environmental data. Finding ways to promote translunar tourism and eventually lunar orbital (or Lagrange point) stations. Finding ways consistent with federal laws to act as an anchor tenant, to champion these new technologies, to fund demonstrator missions, and even to put money aside in escrow for being a leading customer for these new capabilities.

For a short duration before Griffin got in as NASA's administrator, NASA was actually acting in a way to more fully fulfill mandate to "promote commercial as well as international participation "to further U.S. scientific, security, and economic interests." Under the guidance of O'keefe and Steidle, NASA setup several billion dollars worth of "Human and Robotic Technologies" research to help develop and field the technologies that would allow it to more effectively achieve its exploration goals. It was set to operate its exploration architecture in a way to leverage to the maximum extent possible existing and future commercial capabilities. To act as though NASA can't do that is to ignore the fact that that was its very plan up until Griffin took the reins.

I guess the question boils down to what Marburger said: do we intend to extend humanity's economic sphere of influence to include the rest of the Solar System?

Commercial Space Netscape Moment?

I know that I've mentioned on several occasions the hope that at sometime in the next few years, we might see some commercial space company have a "Netscape Moment". The idea being that having a major alt.space company succeed in a very public way (such as SpaceX getting their Falcon vehicles flying reliably enough for them to successfully go public) would likely result in a major positive change in the funding environment for other alt.space firms.

However, Tom Olson had a good post over at Space Cynics today bringing up some issues with the "Netscape Moment" analogy. While I still think that having a successful example of an alt.space company making a good return on investment would help a lot, Tom makes some good points about why that analogy may not actually be the best model for alt.space hopes. I would much rather see an alt.space world where the funding is still tight enough that only the good ventures with good technical and business approaches can get much money, than one in which the money flows so freely that a lot of it ends up being blown on fly-by-night businesses that don't really do anything for solving the challenge of cheap, reliable, access to space.

Just a thought.

Space Tugs vs. Space Ferries: A Useful Distinction?

Something that's been bugging me for some time is the confusion surrounding the term "space tug". The term's been used to describe at least two very different ideas for many years now. At NGEC-2, I tried to inject a little clarity into my working group's discussions by drawing the distinction between "tugs" and what I called "ferries", and I was wondering if others thought it was a useful distinction (and if anyone had a less snicker-drawing nickname then "ferries"--you would think the conference took place somewhere near San Francisco or something from all the chuckles that term drew...)

Under my proposed classification scheme, a "space tug" would be a spacecraft of some sort that primarily is used for maneuvering target spacecraft/objects in the near vicinity of a space station or another spacecraft. For instance, the CSI and CSI/SSL systems proposed for COTS 1 and COTS 1.5 would both fall under this category (and Orbital Express would also likely fit under this category). A "space ferry" on the other hand is a spacecraft that hauls other spacecraft, cargo, or people from one orbit to another in a reusable fashion. For instance, CSI's or Space Adventures' respective "Soyuz-Around-the-Moon" concepts would somewhat be examples of a one-use ferry.

Basically tug == prox ops, ferry == large orbit transfers.

Both are very important capabilities, but while they have some overlap in requirements, many of their requirements lead to very divergent capabilities.

Tugs for instance are explicitly designed for proximity operations in mind. A good tug system implementation would likely have one or more robotic arms for better handling, grappling with, and berthing target spacecraft. A tug likely doesn't have a huge amount of propellant on board. Enough to move things around between various low earth orbits, and to maneuver around the station, but total delta-V capability is probably in the low-hundreds of m/s range. Tugs want to be very robust. The very low delta-V requirements actually make a tug very mass insensitive. So long as most of the things you're moving around are an order of magnitude or more bigger than you, even doubling the mass of your tug has only a minor effect on the total propellant used for tug operations.

Ferries on the other hand are high-performance spacecraft. The delta-Vs necessary for a useful space ferry are on the order of 4-8km/s (though those last 4km/s are probably going to be "dead heading" ie. flying the ferry back to LEO with no payload attached). In the case of a chemically fueled ferry, this means it looks very similar to an upper stage--mostly take, one or two big engines, and some hardware on both ends. An inflatable aerobrake might not be a bad idea depending on how much it weighs. It might not really need much in the way of prox ops capabilities, just navigation and rendezvous capabilities. Ferries are typically going to be much bigger than their cargoes, while tugs will typically be much smaller.

Both ideas also provide different benefits.

The key benefit of tugs is that they enable launch vehicles and their cargoes to be much simpler. Instead of having to come up with a "last mile" solution for every new passenger or cargo spacecraft, you can have a standardized tug interface, and have the tug do all the hard work. That means that it becomes easier for launch providers to get involved in station resupply, because they're now just taking a standardized container, launching it to a specific orbit, and holding attitude until the tug can swing by and pick things up. Right now, most crew or cargo deliveries to the station require a system that uses a complicated service module and prox-ops hardware to actually get to the station, which results in fairly poor launched mass to delivered mass ratios. What tugs allow you to do in the cargo case is to drastically reduce the amount of wasted mass required to deliver a given mass of cargo to a station. Instead of having your cargo vehicle be a fully capable spacecraft, all it is now is a pressure shell, with some tug interface attachment (probably something brutally simple involving a couple of "hand holds"), and a passive CBM adapter on the other end. If you're launching to a station that's in a resonant orbit that provides frequent "first or second orbit rendezvous" opportunities, you might even be able to dispense with the need for power, communications, or even much in the way of thermal management. In other words, the cargo container starts becoming a lot more like your dumb intermodal container that you see on earth (just much lighter...). Tugs can also serve an emergency role for spacecraft that do have their own prox-ops capabilities, by serving as a backup in case something breaks (or in case multiple docking attempts need to be made and the visiting vehicle runs out of maneuvering propellant). Tugs are also a critical enabler for propellant depots. For propellant deliveries, the propellant can go through relatively narrow tubes (compared to what a human could fit through for instance), which means that a tug could allow for a very simple and lightweight standardized propellant transfer interface to be developed that could just be welded into the delivery tank. This interface could be 100% passive--just some mechanical attachment points, and the quick disconnect ports for fluid and if necessary power. A tug with robotic arms could then take all of the complexity onto itself for the fluid coupling. Much better than trying to make an automated docking and fluid coupling system that has to fly on each and every propellant delivery.

In a nutshell, tugs allow you to take all of the most complicated parts of getting people, propellants, and provisions to a station, and offloads it to either the launch vehicle, or to a reusable vehicle that always stays in orbit, doesn't have to reenter, etc. Why lug all of that hardware with you each and every time if you can leave it at the destination. Why require each and every company that wants to launch stuff to a station to then also have to come up with their own prox-ops solution? Solve the problem once, and then you don't have to keep solving it again. If your delivered payloads start outgrowing your tug, the right option might be to build more of them and operate them in a group, instead of designing a newer, bigger model. I think tugboats do just that for very large ships here on earth--instead of building a super jumbo tug, they'll often just use two or three smaller ones.

Ferries provide very different benefits. First off, and most importantly in my opinion is the fact that ferries (when combined with propellant refueling capabilities) allow you to launch a given exo-LEO vehicle on a much smaller, higher-flight rate vehicle. Dave Salt has on many occasions mentioned that an RLV with an 8000-9000lb payload capability could pretty much service the entire GEO satellite market. Most of the mass required in LEO (I know, many GTO launchers don't even stop in LEO, but it's still a useful point) to put a satellite into GEO is not the satellite, or its "beginning of life" propellants--it's the upper stage, its propellants, and the circularization propellants on the satellite. By having a ferry that operates between LEO and GEO, that has refueling capabilities in LEO, you can launch the largest commercial and government exo-LEO missions without requiring anything bigger than a bottom-of-the-line EELV. In fact, you can even launch manned lunar missions using launchers no bigger than an Atlas V 401 or a Falcon IX (a "Phase One" Atlas V might be a little nicer, but not because of the extra payload to LEO, but because the ICES stages envisioned are scalable and potentially much bigger than a stock Centaur stage, and would thus make a great starting point for a passenger transport ferry). For geostationary satellites, ferries can provide an extra service. Because the ferry can deliver things all the way to GEO, the satellite they're carrying could possibly forgo its "main propulsion system" and circularization propellant tanks in exchange for more station keeping tanks, more transponders, more solar panels or what have you. Or, you could leave the main propulsion system on, but have the capability to retire the satellite to a different, lower-value GEO slot, where it could spend its last few years before moving itself to a final disposal orbit. For instance, by the time a satellite is nearing 15 years on orbit, it may be a bit obsolete for first-world markets, but maybe it would still be useful for a different GEO slot servicing locations in the third world, or sparsely populated areas in the Pacific for instance (much like how passenger jets in the US are often "retired" only to be refurbished a bit and sold to third world countries at a much lower price). Either of these can help you get more revenue out of a given satellite launch. There are probably plenty of other benefits of ferries that I'm not thinking of right now, but those are just some thoughts.

Ferries can be based around either chemical or solar electric propulsion systems. Some cargoes don't mind a slow spiral out through the van Allen belts, and thus can be shipped by the more mass efficient (and hopefully therefore more cost efficient) solar-electric "slow boat". Other cargoes (people, cryogens, and possibly GEO satellites) can be shipped via a much faster chemical ferry. Sure, it's less mass efficient, so you're going to be paying for launching a lot more material, but the hardware is relatively cheaper, it can make more flights before being retired, and most importantly, you're not cooking your payload for several weeks in the van Allen belts. For GEO satellites right now, most of their radiation exposure (for their entire 15 year operation timeframe) happens in just one or two passes through the van Allen belts, so minimizing the time spent there might give chemical ferries a leg up (contra conventional wisdom).

Anyhow, what do you guys think? Does drawing this distinction make sense? And does anyone have a term better than "ferry" for a reusable transfer vehicle? Every time I've tried to bring up the idea of a "space ferry" there at the conference, the term would draw smirks or chuckles, or comments along the lines of "I guess NASA Ames is close to San Francisco after all"...

NGEC-2 Summary Part II: Speakers, Ideas, and Memes

In addition to the working groups, there were several speakers throughout the conference. While there most ideas presented at space conferences aren't particularly new, there were a few ideas from the various speakers (and from conversations I had at the conference) that I thought were worth mentioning. This may be a bit random, but I'm going to just list several of the ideas I found most interesting and new.

Buzz Aldrin was one of the breakfast speakers during the conference. Though I was sleep-deprived enough that I couldn't concentrate during most of his talk, he made an interesting (if not heretical) point about "astronauts". The "naut" part of astronaut, taikonaut, or cosmonaut, refers to "nautical"--coming from the concept of an astronaut as someone who knew how to navigate in space. Basically a pilot, an astrogator, someone who knows orbital dynamics, and knows how to fly spacecraft. His point was that not everyone who flies on a vehicle in space is an astronaut. I think he was saying this to try and distinguish space tourists from actual NASA astronauts, but I think his point is more interesting than that. For most space flights, you really don't need more than one or two astronauts. Most of the people who fly into space don't need to know how to navigate by the stars, or how to plot a trajectory, or how to null out the rotations on a vehicle. You might want a backup pilot, but not everyone who flies into space needs to or should be a fly-boy. Now, there's a bit of an emotional appeal to the idea of being able to call oneself an astronaut because one flew over 100km, enough so that it's probably still worth leaving that tradition in place for now--my point was just that those paying space travellers don't need to be trained or treated in the same way as a career spacecraft pilot.

Taber MacCallum of Paragon Space Development Corp gave probably the most interesting talk at the conference. Some of the earlier talks had copies of the slides posted on the NGEC-2 site, so I thought they were going to do the same for Taber's talk. Alas, as of the last time I checked, this didn't turn out to be the case. If anyone can snag me a copy of his presentation, that would be greatly appreciated. Taber and his wife were members of the original Biosphere 2 team, and he spent at least part of his time talking about lessons learned from that project. The biggest and most important part of his presentation was about the role of "leadership" in entrepreneurial ventures. He made the point that I've made in several instances that entrepreneurial ventures are high-stress, high-ambiguity environments. As I understood it, his point was that leadership in many cases boils down to emotional maturity. How we deal with our egos, with stress, with uncertainty, and with critical decisions. He made the interesting point that when a person gets identified too closely with a certain technical project or solution, it's often easy to allow the success or failure of that project to become intimately tied to one's self-worth. In such situations it becomes very hard to act objectively, and very easy to act in an emotionally immature fashion. I've seen this before (a lot) in myself, and I think that most readers could probably find examples in their own lives of such shortcomings. I know that when I've been championing an idea, and shoots holes in it, that sometimes I end up becoming very defensive, and will actively start blocking out evidence that contradicts my position. I usually calm down later, apologize, and get back to work. But it's a valid point--and an extremely dangerous one for entrepreneurs (or other people in leadership positions). As one person put later on in the conference, the single most likely thing that could hinder the development of commercial space is the personalities of the key players involved. Ironically, I think he might be right. While the technical, financial, and market obstacles are real and severe, the emotional, ego, and personality challenges may actually be more important in the long run. Just a thought.

Another interesting idea came up in the discussion in our lunar access working group about space ferries. One of the members of our team was an engineer at a major commercial satellite manufacturer. On several occasions, when discussing various alternative commercial means for delivering satellites to orbit or to GEO, I've had friends like Dennis Wingo bring up the risk aversion of the satellite manufacturers/launchers as an insurmountable show-stopper. As the logic went, launch costs are such a small percentage of the overall costs (and minuscule compared to the future revenue streams) that doing things that would reduce launch costs wouldn't really be very interesting to satellite builders/launchers, because the risk of doing something new would be too high. I had been repeating this conventional wisdom, when my teammate suggested a slightly different viewpoint. He agreed that satellite builders and launchers were very risk averse, by necessity. They really don't want to buy the first flight of some new transportation concept. Higher risks correspond with higher liability premiums. However, he made the point that after the initial risk has been reduced through a demo (or preferably two or three), that launch costs actually end up being very important. He said that while launch costs weren't the majority of the cost of building, launching, and activating a satellite, they were significant, and investors and customers really hammer on them to try and find the best deals they can. The fact that people are willing to launch on rockets with known worse reliability track records (Ariane V and Sea Launch for instance) in order to get a better launch cost should put to lie the idea that satellite builders and launchers are so risk averse that they'll never get involved in a new technology until after its been in service for a long time. One shouldn't assume that they'll be able to just sign customers up right from the start, but at least from what he was suggesting, the barrier to entry into supplying services to that market might be a little lower than I had originally suspected. Another idea that came up in the conversation was that the sooner you could convince insurers that your service provides a net decrease in risk, the more likely they'd be leaned on by customers and investors to take advantage of that service (in order to lower their premiums). Once again, just some more food for thought.

Another interesting point, brought up by Ken Davidian regarded the aging of the NASA workforce. At the time of Apollo 11, the average age of a NASA employee was about 29 years old. Now it's over 55. This has very important ramifications for the future of NASA and commercial space development, particularly with Griffin's statements on several occasions that NASA was going to be relying on more experienced engineers for Constellation, instead of hiring on a bunch of younger engineers for the project.

Unfortunately, I've been asked not to blog about one of the most interesting new ideas that I heard at the conference. Maybe at some point once my friend has had more chance to spread his meme from inside the agency I can blog about it without risking getting the idea tossed out as being "Not Invented Here".

Lastly, in addition to the working groups and the planned speakers, this conference ended up being a great chance for networking. I finally got to meet Grant Bonin in person (he's been trying to rope me into writing a commercial Mars transportation white paper for a while now). I got to meet a few people from the NASASpaceFlight forums. On Wednesday night, Tiff and I (and some friends from Santa Clara) got to go swing dancing in San Francisco, and we were able to arrange a meeting with Jake McGuire (who I've known from the sci.space.* newsgroups for over 11 years now). And on Friday night we had dinner with both Henry Cate's. For the conference, we were staying at the house of the one who hosts the Bay Area Moon Society meetings, and on Friday we had dinner with him and his wife and several of his kids and their families. His son Henry is the one who started the Carnival of Space last year.

I hope they have another conference like this next year. The work was fun, but I enjoyed getting to finally meet some of these people even more.

Next Generation Exploration Conference 2 (Part I)

Apparently unbeknownst to most people in the space blogosphere, there was a second space related conference going on in Silicon Valley this past week (at about the same time). This conference, the second "Next Generation Exploration Conference" was an invitation-only conference for young, "emerging global space leaders" put on by NASA's Exploration Systems Mission Directorate's "Commercial Development Policy" group (now headed by Ken Davidian), and by NASA's Innovative Partnership Program. The focus of the working conference was commercial opportunities in cislunar space, and our goal was to put together a document overviewing some of the commercial opportunities in cislunar space, fleshing out some detail on the nearest term and most feasible of those opportunities, and making suggestions to NASA (and industry/academia) on what could be done to help enable those opportunities.

It was a lot of fun. I missed the first day (due to an important meeting we had down in Mojave on Monday and Tuesday) of the conference, but was able to make it there in time for the start of the working groups.

I was worried at first that with the sponsor being ESMD, and with the "alt.VSE" conference going on across town at Stanford at the same time, that there would be lots of pressure to turn the conference in a NASA-centric direction. In the preplanning discussions, I got chastised by one of the other attendees for suggesting that the Constellation architecture and Global Exploration Strategy didn't serve as much of a "point of departure" for the working groups, since it was pretty much irrelevant to commercial lunar development. I was worried that the desire to toe the NASA line would end up turning the conference into a brainstorming session for NASA-serving lunar businesses that 20 years from now might be feasible if NASA happens to get its architecture built and lunar base started.

Fortunately, Ken was able to find a way to focus the conference that was much more productive without degenerating into Ares-bashing, which I tend to be frequently guilty of. First, he made an important distinction between "commercialization" and "commercial development". I wasn't at the conference on the day he explained this concept, but as I understand it, "commercialization" is more or less taking some NASA-provided function, and contracting it out to the private sector. This could be things like "commercial" ISS resupply, where NASA is having the private sector serve it in a more cost effective manner than it could do on its own. "Commercial development" on the other hand is when a commercial actor creates a good or service to meet the needs of various groups, among which NASA may or may not be one of them. For instance, if a company were to develop a crew/cargo transport vehicle for servicing Bigelow stations as well as the ISS, that might be more of a commercial development. His point was that while commercialization was good, true commercial development was better. The other thing Ken did was to suggest focusing primarily on near-term projects taking the current status quo as the point of departure.

Anyhow, with that focus, we split up into working groups. I joined the "Lunar Access" working group, which consisted of several NASA employees (including several people from the COTS program), several university students, and a couple of people from "Big" aerospace, and one or two other representatives of the entrepreneurial space access community (including the guy at SpaceX who is in charge of most of their lunar business development).

We started out by looking at the long-term of what kind of commercial ecosystem we'd like to see in cislunar space over the next few decades, and then focusing back on transportation segments and business opportunities that were either feasible now, or that needed to be started in the near term. The big conclusion we came to was that the transportation needs of commercial lunar ventures (frequent access, low marginal cost, etc) did not line up very well with the planned Constellation architecture, and that therefore commercial lunar transportation would be important for a lunar ventures. We weren't necessarily suggesting abandoning Constellation, just stating that for non-governmental ventures, other transportation options needed to be available. So as I said, we worked back to the near-term to figure out what steps would need to (and could be) taken in the near term, and spent most of our time fleshing out the ideas that we came up with. I'll probably go into more detail in further blog posts, but the seven opportunities we found most interesting were:

• Developing off-the-shelf Automated Rendezvous and Docking systems
• Space Tugs
• Space Ferries (I'll go into the distinction between these two in another post)
• Propellant Depots
• Standardized Lunar Microlander Buses
• Testbeds for proving out technologies on orbit
• An ESPA-ring derived secondary payload system for lunar payloads
  

I was mostly involved in the second, third, and fourth ideas. So, we fleshed each of these ideas out, including putting some thoughts down into who could use these services, who might be actors in supplying or helping develop these services, what things NASA or industry could do to enable these opportunities, and what sort of time frame these things would likely occur in. It probably would help if next time they do this, they involve more business people, particularly among the mentoring/moderating staff (most of the people in my group were engineers). I imagine it shouldn't be too hard to find angel investors, VC managers, and other Silicon Valley entrepreneurs who are interested enough in space, and interested enough in working with young people to help provide a more thorough business analysis. But, as it is, the results we were able to put together were at least rather informative. Once the finalized document we produced is ready, I'll post a link to it so you all can see more of what we came up with.

LM/Bigelow Atlas V Deal

For those who didn't see it on Hobbyspace, I got interviewed yesterday by New Scientist about the recent LM/Bigelow announcement. All in all it was a pretty good article (though apparently we might need to update our website to reflect the fact that we haven't been in Santa Clara for over a year and a half...). I had a few other thoughts about the announcement that I figured might be worth sharing, for what its worth.

In the quote they selected for the article, they mentioned my question of "will they be able to drum up enough demand to justify the flight rates they're talking about." Here were some of my thoughts that I shared with David Riga (the author of the New Scientist piece), that didn't make the cut:

If he were just running an orbital hotel (he isn't), I'd be very skeptical. Instead I'm somewhere between skeptical and guardedly optimistic. While there haven't been large numbers of takers for flights on the Soyuz, what Bigelow's offering is fundamentally different. Flight opportunities are frequent (which is critical for most microgravity research programs--imagine trying to run an R&D lab that you could only visit once or twice a year!), the situation is more customer friendly, training would likely be more streamlined (I hear that for Soyuz training the "passenger" is actually more of a third crew member than an honest-to-goodness passenger), etc.

It'll be interesting to see if he can pull off his idea of forming an international astronaut corps for countries that don't have their own space program. It wouldn't have all the usual glory of having your own national launch system, but it also wouldn't have the waste of it either. Countries like the UK could look at it as a smart and low-cost way of doing a manned space program--why reinvent the wheel when you can just buy a ticket and focus on doing something in space instead of blowing billions just getting there?

Also, the title of the New Scientist piece is somewhat misleading (though David may not have had anything to do with the title). There are some major hurdles for using Atlas V to fly people to Bigelow's station--it's just that most of the major risks don't lie with "man-rating" the Atlas V (or whatever you want to call making reasonable adaptations for flying a capsule on an ELV). Continuing with some more thoughts that didn't make the cut (yeah I wasn't expecting David to use every word of my several page response...):

Most of the challenges fall into two areas: developing a market at the pricepoint Bigelow can offer with existing transportation systems (like a "man rated" Atlas V), and finding a capsule developer who can raise the money and technically execute on doing such a capsule. I think the technical risk for both parts is relatively low--this has been done before even if there are still some improvements needed over previous systems (Mercury, Gemini, Apollo, Soyuz, etc) to make it commercially viable. Most of the risk is on the marketing and financing side of things.

If Bigelow is able to start signing up high-visibility customers though, look to see that change. Once there looks like there's going to be enough demand to justify a capsule project, I think it'll be much easier to raise money for [developing] it.

Lastly, discussing whether I thought that the Atlas V was a good choice for Bigelow, I said:

I think at the moment they're a pretty good choice. The good news is that with SpaceX also hopefully getting into the launch business soon, that'll provide the competition Bigelow needs to keep prices low. Obviously, it would be great if there were high-flight-rate commercial RLVs instead, but those really need a proven market in order to justify the funds needed to pull them off. So short term, I think this may be Bigelow's best bet. In the longer term, it'll be up to LM to find ways
to keep themselves competitive.

To elaborate on this last point a bit, the price points Bigelow has been talking about (~$15M per person for a 1 month stay) and which a system based off of the existing Atlas V could likely deliver are probably too high for there to be a lot of space tourism demand. Fortunately, as Bigelow has mentioned a lot of times, he isn't running a space hotel. In order to really start getting to the elastic portion of the demand curve, the price tag would probably need to be a bit lower--on the order of $2-5M per ticket (according to some reanalysis of the old Futron Space Tourism study that T/Space did a few years ago that I discussed in this old blog post). It may not actually be as impossible for LM to deliver numbers at least on the high-end of that scale as I used to think (they have some possible tricks up their sleeve if the demand for Atlas V flights was high enough to justify the investment), and if Bigelow can actually deliver on demand for 80+ people to his station in a given year it might also be enough to close the business case for a high-flight rate, small RLV. But neither of those options are likely to happen right away. So, while someone like Space Adventures could probably rent some of his facility for space tourists, at the price point they are talking about, I'd be surprised if they could fill up more than 1-2 of the 12 targeted flights per year with actual "space tourists".

That leaves Bigelow's "sovereign" and "prime" customers to make up the rest of the 10 flights worth of demand. Admittedly one should note that not all of the 12 flights per year are going to be people--I'd imagine that at least one will be consumables, cargo, reboost propellants, etc. And on some flights I imagine that some of the passenger seats might be exchanged for experiments, research hardware/raw materials, and other commercial cargo.

The good news is that if they're really providing 12 missions per year, that's a monthly flight. While that still isn't phenomenally great for a microgravity research program (see Ken's last post, and my last space post and these posts from the ACES conference two years back for why flight rate is important for such programs), it's substantially better than the existing state of practice. As was stated in the first of those two ACES posts, when people know that there's going to be a flight every month to the station, it's a lot easier to slip last minute experiments or small hardware on-board at the last minute. Scientific research often lives or dies on iterations--on how fast you can experiment, analyze, reformulate, rehypothesize, and get to your next experimental step. What this means is that while 12 flights a year at $15M per seat isn't perfect for orbital microgravity research, it might actually be good enough to start generating some real demand--ie the "tipping point" where orbital microgravity demand starts picking up might be a little higher than orbital tourism, and possibly high enough to fill up at least a chunk of those 10 remaining flights.

But like the space tourism demand, that demand is only going to be able to grow if Bigelow can provide enough demand for the rest of those flights. Which brings us back to the "sovereign" customers that Bigelow has mentioned on several occasions. The idea being that this would provide smaller countries a much cheaper way to get involved in manned space flight. At least one country I know of might be in an ideal position to take the lead on this venture: the UK.

As Duncan over at the Rocketeer blog has mentioned on several occasions, this might be a good way for the UK to get back into manned spaceflight as they have recently been discussing more seriously. It's interesting to note that the premier suborbital tourism venture involves a US launch provider and a British operator, so the idea of the UK buying tickets to a US owned commercial station on US owned and operated launch vehicles could be framed as being the new way of doing things. As I mentioned above, by letting someone else spend the money on the destination and the transportation, the UK could focus on actually doing something useful with people in space, instead of blowing so much money on the first two categories that they have little left for actually accomplishing something. This would be a very forward-thinking thing for the UK to do. And if they took the lead in signing up for such a program, it is very feasible to believe that you would see other nations following their lead. I'm thinking of other Anglosphere countries like Canada, Australia, New Zealand, South Africa, and possibly even India. It wouldn't take too many of them running small low-cost astronaut corps and doing their own research projects on Bigelow stations before you could start providing enough demand to see those kinds of flight rates. Or at least it doesn't seem to unrealistic to imagine it.

So, at least on the surface it might be possible for Bigelow to pull this off--but he's going to need to sign up some high profile customers sooner rather than later. In the medium and long term, if Bigelow is able to provide enough demand for that many Atlas V flights, LM is going to have a lot of competition. From SpaceX and from other corners. But that's a problem that I'm sure we would all love to have...

Discussion of Dr. Griffin's STA Comments on ESAS

I've had several people in several places ask me if I was going to do a point-by-point rebuttal of Mike Griffin's comments to the STA this week (for reference the text of his comments is available here). While I don't have the time to go into every single disagreement I have with what he said, I think there are a couple of key points I would like to point out. In other words, I've come to discuss Griffin, not to Fisk him.

Missing the Vision

Dr Griffin starts his defense of the chosen Constellation architecture by framing it "in the
context of policy and law that dictate NASA’s missions." As he said on page 2:

Any system architecture must be evaluated first against the tasks which it is
supposed to accomplish. Only afterwards can we consider whether it accomplishes
them efficiently, or presents other advantages which distinguish it from competing
choices.

He then went on to discuss President Bush's original announcement of the Vision for Space Exploration, and the NASA Authorization Act of 2005. I agree that it is important to make sure you know up-front what yardstick your program is going to be measured by. However, I think one thing becomes quickly obvious as you read Dr Griffin's quotes from those documents--he entirely focuses on the technical implementation details, and never once mentions the actual policy goals!

Quoting from "A Renewed Spirit of Discovery: The President’s Vision for U.S. Space Exploration":

Goal and Objectives
The fundamental goal of this vision is to advance U.S. scientific, security, and economic interests through a robust space exploration program.

These goals are the yardstick by which any VSE implementation needs to be judged. The rest of the technical details of how the space exploration program is carried out needs to be viewed in the light of these three areas of US interests. It doesn't matter if a proposed implementation hits all of the other technical details, if it doesn't really further US scientific, security, and economic interests, it isn't really compliant with the goals of the president's Vision.

Going into a little more detail on these goals, the Renewed Spirit of Discovery document continues (emphasis mine):

In support of this goal, the United States will:
• Implement a sustained and affordable human and robotic program to explore the solar system and beyond;
• Extend human presence across the solar system, starting with a human return to the Moon by the year 2020, in preparation for human exploration of Mars and other destinations;
• Develop the innovative technologies, knowledge, and infrastructures both to explore and to support decisions about the destinations for human exploration; and
• Promote international and commercial participation in exploration to further U.S. scientific, security, and economic interests.

Once again, all of the specific technical details like the CEV, retiring Shuttle in 2010, etc. are all pursuant to these goals.

Lastly, the NASA Authorization Act of 2005 (available here) states, once again with my emphasis:

The Administrator shall establish a program to develop a sustained human presence on the Moon, including a robust precursor program, to promote exploration, science, commerce, and United States preeminence in space, and as a stepping-stone to future exploration of Mars and other destinations.

Once again, you will notice that the key goals of this Vision, elucidated by both the President and Congress include not only science, but commerce, and in the president's case security.

I could go on about how Dr Griffin's focus on the parts of the Authorization Act that talk about heavy lift and shuttle derived ignored other sections in the act that talk about "encouraging the commercial use and development of space to the greatest extent practicable" (see Section 101.a.2. parts B-C). But I think the fundamental issue is that by focusing exclusively on just the technical side of the requirements, and not on the underlying goals, Griffin is missing the Vision.

Growth Potential

On page 7, Dr. Griffin starts making his case for the Constellation architecture with this somewhat ironic statement about the Space Shuttle:

Once before, an earlier generation of U.S. policymakers approved a spaceflight architecture intended to optimize access to LEO. It was expected – or maybe “hoped” is the better word – that, with this capability in hand, the tools to resume deep space exploration would follow. It didn’t happen, and with the funding which has been allocated to the U.S. civil space program since the late 1960s, it cannot happen. Even though from an engineering perspective it would be highly desirable to have transportation systems separately optimized for LEO and deep space, NASA’s budget will not support it. We get one system; it must be capable of serving in multiple roles, and it must be designed for the more difficult of those roles from the outset.

And then Dr Griffin goes on to try and justify an architecture based on building a duplicative LEO capable only launch vehicle first, and hoping that when that vehicle is finally done, that there will be funding for developing "the tools to resume deep space exploration"...

After that auspicious start, Dr. Griffin then reminds us that "the new system will and should be in use for many decades." Of course some of the historical analogies he draws could lead one to different solutions than it led him. For instance, he mentions that "In space, derivatives of Atlas and Delta and Soyuz are flying a half-century and more after their initial development." An interesting thing to note about Atlas and Delta is that the only reason why vehicles with the name Atlas and Delta are "still flying" a half-century after their initial development, is precisely because they are only derivatives of the original. In fact, the current EELVs have very little in common with the vehicles that originally bore their names.

On pages 8 and 9, Dr. Griffin concludes that (emphasis mine):

The implications of this are profound. We are designing today the systems that our grandchildren will use as building blocks, not just for lunar return, but for missions to Mars, to the near-Earth asteroids, to service great observatories at Sun-Earth L1, and for other purposes we have not yet even considered. We need a system with inherent capability for growth.

While I disagree with the direction Dr. Griffin is going, I do agree with his point in that last sentence. We do need a transportation architecture that has inherent capability for growth. I just don't think that the Constellation architecture really fits that bill.

The Promise of Commercial Space

Now, lest you think I'm going to spend yet another post hammering on Dr. Griffin, I'd like to quote a part of his speech that I really agreed with:

Further application of common sense also requires us to acknowledge that now is the time, this is the juncture, and we are the people to make provisions for the contributions of the commercial space sector to our nation’s overall space enterprise. The development and exploitation of space has, so far, been accomplished in a fashion that can be described as “all government, all the time”. That’s not the way the American frontier was developed, it’s not the way this nation developed aviation, it’s not the way the rest of our economy works, and it ought not to be good enough for space, either. So, proactively and as a matter of deliberate policy, we need to make provisions for the first step on the stairway to space to be occupied by commercial entrepreneurs – whether they reside in big companies or small ones.

I have to say that for all my disagreements with Griffin, he at least talks a good talk when it comes to commercial space. I full-heartedly agree with his point in this paragraph. When you think about it, even assuming everything works out according to his plan, Constellation is never going to be capable of supporting more than a dozen people off-planet at any time. While that may be a lot more than we have now, Ed Wright has a point when he says that that is a round-off error, not an exploration program. Basically, the only way we're going to see large numbers of people off planet, and the only way we're going to see the large-scale manned exploration and settlement of our solar system in our life times, is if the private sector can eventually play a much more expansive role in space transportation. As it is right now, so long as the commercial industry continues to play second fiddle to parochial interests and NASA-centricism, we're not really going to go much of anywhere.

So, the fact that NASA is at least doing something to help promote that day is a sign that they at least partially get it. A successful and thriving entrepreneurial space transportation industry is going to help them actually achieve their goal of extending human life throughout the solar system in a robust program of space exploration.

Griffin continues with more good comments in his next paragraph:

If designed for the Moon, the use of the CEV in LEO will inevitably be more expensive than a system designed for the much easier requirement of LEO access and no more. This lesser requirement is one that, in my judgment, can be met today by a bold commercial developer, operating without the close oversight of the U.S. government, with the goal of offering transportation for cargo and crew to LEO on a fee-for-service basis.

But here is where the conversation takes a dangerous turn:

Now again, common sense dictates that we cannot hold the ISS hostage to fortune; we cannot gamble the fate of a multi-tens-of-billions-of-dollar facility on the success of a commercial operation, so the CEV must be able to operate efficiently in LEO if necessary. But we can create a clear financial incentive for commercial success, based on the financial disincentive of using government transportation to LEO at what will be an inherently higher price.

To this end, as I have noted many times, we must be willing to defer the use of government systems in favor of commercial services, as and when they reach maturity. When commercial capability comes on line, we will reduce the level of our own LEO operations with Ares/Orion to that which is minimally necessary to preserve capability, and to qualify the system for lunar flight.

While I agree that the government not only is the government being "willing to defer in favor of commercial services" is a really good idea, I think that this approach (of hedging their bets by coming up with a competing in-house launcher) is fraught with risk. Also, while on first blush, it may appear to be common sense to not "hold the ISS hostage to fortune", it is my contention that this line of reasoning not only doesn't hold as much water as it seems.

First off, as has been pointed out on numerous occasions, including in Griffin's statements above, a commercial solution to ISS crew/cargo is going to be a lot more affordable than the in-house Ares-1/Orion solution. It has been mentioned before by people high up at NASA, that they really need COTS to succeed, because if they have to fly all the ISS missions themselves (especially if ISS doesn't get retired in 2016, which Dr. Griffin mentioned in this speech as a possibility), there really won't be anywhere near enough money to develop the lunar portions of the proposed Constellation architecture in time for the 2020 lunar return goal. You could say in a way that the existing Constellation architecture holds the rest of the Vision hostage to the fortune of COTS. If COTS doesn't succeed, there's no way NASA is going to be able to afford executing on the rest of the vision. If the supposed "backup plan" for ISS resupply won't produce acceptable results anyway if COTS doesn't turn out, NASA shouldn't be trying to make it a backup plan at all--they should invest more heavily in making sure that there are multiple COTS competitors and that they have enough resources to succeed. One of the single biggest execution risks for any COTS company is financing risks. And having a NASA "backup plan" that could potentially compete with them is one of the single biggest obstacles to be overcome in raising money for a COTS team.

Which brings me to my other concern. The danger of having NASA in-house launch vehicles and space access capabilities that can serve as a backup to COTS also allows them to directly compete with COTS if the budgetary situation goes sour. Think about it. If Ares-1 finally gets built and working, but Ares-V doesn't get funded, there's nothing for Ares-1 to do but service ISS. With how hard the esteemed congressmen from Florida, Utah, and Alabama are fighting to maintain the Shuttle workforce and infrastructure (even to the point of suggesting continuing to fly the Shuttle!), does anyone really think that they would just "stand down" at that point, even if there was a clearly superior commercial alternative? Not very likely. I'm sure they would come up with some technical reason why Ares-I was superior (after all, our probabilistic risk assessment says that Ares-I has a 1:2106.5923 chance of killing a crew, while our numbers show that they have a 1:500 chance--who do you want flying our brave astronauts?) and find a way to not actually stand down. The frustrating thing is that by setting things up the way NASA is doing, the NASA people don't even have to be malicious for such a result to happen--it's a natural and likely consequence of the perverse incentives that NASA and Congress are setting up.

So, while I personally think that Dr. Griffin really and emphatically believes in and supports commercial space development, I'm afraid that there's a high chance that some of his well-intended choices could end up coming back to haunt us.

Moon, MARS!!!! and Beyond

The last item I'd like to point out in Dr. Griffin's speech is one of the justifications he used for the "1.5 launch" architecture they selected. Dr. Griffin made the point that while he feels that Constellation needs to be backward compatible with ISS as a backup plan, it also needs to be forward compatible with Mars, because sometime in the 2030s, we're going to be going there. Now, I'm of the opinion that trying to guess what the best technical approach will be for a problem 30 years from now is somewhat of a fools errand. But that's just me I guess.

So, starting on page 16 he begins to layout his case:

On the other end of the scale, we must judge any proposed architecture against the requirements for Mars. We aren’t going there now, but one day we will, and it will be within the expected operating lifetime of the system we are designing today. We know already that, when we go, we are going to need a Mars ship with a LEO mass equivalent of about a million pounds, give or take a bit. I’m trying for one-significant-digit accuracy here, but think “Space Station”, in terms of mass.

Now, I'm not going to go into the fact that there are probably plenty of other approaches to Mars exploration that can change the equation entirely. That's a post for another day. For now, let's just run with that premise.

He then repeats the "everyone knows that ISS taught us that using 20 ton vehicles to build something big is a bad idea" catechism, but that's not what I'd like to discuss. The real gem is in this paragraph on page 17 (emphasis mine):

But if we split the EOR lunar architecture into two equal but smaller vehicles, we will need ten or more launches to obtain the same Mars-bound payload in LEO, and that is without assuming any loss of packaging efficiency for the launch of smaller payloads. When we consider that maybe half the Mars mission mass in LEO is liquid hydrogen, and if we understand that the control of hydrogen boiloff in space is one of the key limiting technologies for deep space exploration, the need to conduct fewer rather than more launches to LEO for early Mars missions becomes glaringly apparent.

It is true that one can draw that inference--that hydrogen boiloff means you should build as big of an HLV as possible. However, the conclusion I would draw is that if cryogenic propellant storage technologies are "key limiting technologies for deep space explortion", then the right answer is to stop trying to kludge around the problem--develop them! Don't use the existing state of the art in propellant handling and problems that are still 20 years down the road drive multi-billion dollar development projects today.

There are current technologies under development that could yield very low to zero boiloff of cryogenic propellants. There are multiple groups (ULA, Boeing, groups working with Glenn Research Center, etc.) pursuing multiple approaches to solving these problems. There are passive cooling and active cooling techniques. This isn't some high-risk technology like nuclear fusion. The technologies needed for cryogenic fluid management in space are mostly low-risk extensions of 40 years worth of research and development. More to the point, many if not all of these technologies need to be developed to make Constellation work for lunar trips anyway, and would still be needed for Mars trips.

Is 2030 really so close that we can't afford to do this right and actually develop the technologies we need instead of trying to kludge by with existing technologies?

Once you have the boiloff issue reduced or solved, that ~500klb of hydrogen ceases to be a headache, and begins to be an opportunity. That's a lot of demand for propellant in orbit, and it can be supplied commercially. You're already going to need propellant transfer technologies anyway if you have to launch the hydrogen in multiple launches, so what's to stop launching it in even smaller launches?

I guess my point is that if one of the key arguments for the 1.5 launch architecture over a more commercial one, or a less expensive shuttle derived one like DIRECT is hydrogen boiloff, I think their kludge around the issue isn't the right approach, and that they'd be better off just doing it the right way. Also, part of the reason why we have a federally funded aerospace program is to help prove out the technologies necessary for enabling the commercial exploitation of space, and actually solving problems like these would be much a much more responsible use of public funds than developing a kludge around point design like Ares V that doesn't advance the state of the art for the commercial benefit of the country.

Conclusions

I guess overall while there were some good points, there was also a lot of issues with Dr. Griffin's latest defense of Constellation. As discussed, I think that an a myopic focus on the technical details while ignoring the overall goals of the VSE has led to an architecture that isn't responsive to the key policy goals laid out by the president and reiterated by Congress (particularly with respect to promoting the commercial and security interests of the United States). I think that in spite of Griffin recognizing the need for growth and flexibility in any architecture, that he chose a rather brittle and inflexible one. I also think that while he showed that he does recognize the potential of commercial space, and the importance of NASA trying to promote it, I think that the way he's running COTS and Constellation will likely end up being highly counterproductive. Lastly, I think that in many cases, when confronted with a solvable engineering problem, Constellation has instead decided to kludge around the problem instead of properly solving it.

There are plenty of other issues I could've raised, but I figured these were some of the more obvious ones that I felt needed discussion.