27 October 2006

SpaceX COMSTAC Briefing

Clark Lindsey posted some links on Hobbyspace to a recent presentation given by SpaceX at COMSTAC. The Briefing had some interesting pictures and information, and this one at least doesn't appear to have any sort of statement saying it shouldn't be distributed, so if they don't mind, I'm going to post a few of the pictures and a couple brief thoughts.

There isn't really all that much that's new in the presentation, but I did notice that apparently my understanding of their tank design was a little bit off. I thought they were using a design that had the tank walls, with a couple of ring stiffeners, but no stringers. I was wrong. So, in a way this is just a 21 century Friction Stir Welded version of how an aircraft wing is designed.


It's also interesting to note that they appear to have resolved their supply issue with Lithium Aluminum. That's good. LiAl is interesting stuff--really good fracture toughness, with excellent strength-to-weight. And if you're using FSW for the welds, you get around a lot of the weird processing issues.

But the coolest bit from the summary was their pictures of the Merlin 1C. Apparently the powerpoint file has some pretty sweet high-res pictures. Back in the summer of '03, before I got involved with Masten Space Systems, I paid a visit to their rocket factory. Their VP of Business Development, Gwynne Shotwell was nice enough to give me a tour of the place, and I was interviewed by Chris Thompson (then VP of Operations and Manufacturing). During the interview, we got talking about pintle injectors, since I had a fascination with the design, and SpaceX was using it. Chris told me that he and Tom Mueller and a few others of the original SpaceX crew had done some ameteur pintle injector based rockets over the years. When I showed him my designs I had done as part of a special projects class at BYU, he smiled and said something along the lines of "my, that looks familiar". I'm not trying to be rude or belittling in any way, but when I saw those pictures I thought the same thing--"my, that looks familiar."


Those first two are pretty obvious, and quite gorgeously done. This last one I think is a tube-wall nozzle extension, possibly for the upper stage version of the Merlin-1C. But I could be wrong. It might also be part of the closeout for the milled-wall chamber. Either way, it is rather impressively done. Though having a swirl like that in the nozzle tends to create a torque on the stage, which will induce a roll unless counteracted by the turbopump exhaust or RCS thrusters. My curiousity is definitely piqued.

Overall, I'd say that these engines look very nice, and I hope they have as much luck and success with their regen cooled pintles as we have--it's definitely the right way to go. The designs are a lot more complicated than our designs, but probably a lot higher performance and a lot lighter weight than ours too. Tom Mueller's team has outdone themselves. Having a real cooling system on their engines I think compliments an already quite impressive design. Now if only we could talk them into getting a real landing system to go with that stage...

Space.Com Lunar Lander Challenge Article

Leonard David has a good article up on Space.com about us and Armadillo Aerospace. Now that we have a full year to get our vehicles up and running, and as much flight experience as we can, I think that people will take us a lot more seriously as a competitor. John mentions that we have to build another vehicle after XA-0.1 to compete, and while right, the next vehicle will pretty much be using the exact same engines, computers, valves, regulators, and landing gear as XA-0.1 (unless we find some issues that require big changes). Most of the parts that will be upgraded are either purchase parts (carbon fiber pressurant tanks), or structural pieces like tanks and frames. Most of the really tough parts (the electromechanical systems, and engine systems) will be wrapped up this year.

Armadillo is pretty close to having a level one capable vehicle, but I hope John doesn't plan on getting too complacent. They not only have to make the minimal qualifications this time, they need to win in the flyoffs. And that requires a vehicle that is a lot more robust and reliable than their entries for this year. I'm sure John and his team know that though, and we'll be in for a tough competition this year.

26 October 2006

New Space Policy

Ok, I finally got around to perusing the new US National Space Policy that came out a few weeks ago. Most of the noise I've heard so far has been by people attacking the policy for being too belligerent. While I can see one or two sentences in there that could possibly have ominous interpretations, I think that some of the rhetoric in that direction is a wee bit overblown. It is a wee bit belligerent, but I don't think the current administration could recite their ABCs without being at least a little bit bellicose. You live, you die, you get over it.

What deserves far more attention was all the language in there regarding commercial space. I'll just quote a bunch of it:

From the last bullet point in Section Four [emphasis added in italics]:
Strengthen and Maintain the U.S. Space-Related Science, Technology, and
Industrial Base.
A robust science, technology, and industrial base is critical for U.S. space capabilities. Departments and agencies shall: encourage new discoveries in space science and new applications of technology; and enable future space systems to achieve new and improved capabilities, including incentives for high-risk/high-payoff and transformational space capabilities. Additionally, departments and agencies shall: conduct the basic and applied research that increases capability and decreases cost; encourage an innovative commercial space sector, including the use of prize competitions; and ensure the availability of space related industrial capabilities in support of critical government functions.

That part about space prizes is amusing seeing as how the two agencies offering prizes (DARPA and NASA) are either being stripped by Congress of funding or authorization for doing such prizes. Hopefully that can be fixed before too late. It's already a pity that such a miniscule part of DARPA and NASA's funding is going to such productive ends--outright eliminating those prizes would be a travesty.

There were lots of other good quotes in Section Seven [also with emphasis added]:
Use U.S. commercial space capabilities and services to the maximum practical extent; purchase commercial capabilities and services when they are available in the commercial marketplace and meet United States Government requirements; and modify commercially available capabilities and services to meet those United States Government requirements when the modification is cost effective;

Develop systems when it is in the national interest and there is no suitable, cost effective U.S. commercial or, as appropriate, foreign commercial service or system that is or will be available when required;

Continue to include and increase U.S. private sector participation in the design and
development of United States Government space systems and infrastructures;

Refrain from conducting activities that preclude, deter, or compete with U.S. commercial space activities, unless required by national security or public safety;

Is anyone else surprised that Griffin isn't trying to draw too much attention to this new policy? I have to admit that this policy is overall pretty darned good. Especially the section seven stuff. I tend to be rather hard on this administration when they do stupid stuff, but I think that I ought to at least say something good when they come up with a good policy.

Now it'd be nice if they actually had the balls to tell Griffin to actually pay attention to it. Anyone want to guess what the probability of that is?

24 October 2006

X-Prize Cup

Well, now that I'm back from Las Cruces, I figured it might be good to wrap up the Masten Space Systems X-Prize Cup 2006 saga, picking up where I left off.

Before I go into the more detailed story, I'd like to thank the X-Prize Cup people, and particularly our pad manager Alan Perryman and our safety officer, Vince Hill. Alan and Vince were extremely professional, and were a lot of fun to work with. They've got a standing invitation to come out and join us for a test whenever they want. The rest of the X-Prize Cup volunteers gave it their best, and at least by the end of Friday had really hit their stride. Thursday and Friday morning were a little bit rough around the edges, but they came through for us in the end.

Anyhow, Thursday, the weather was much nicer, and we set about getting the trailer ready for the show. We made a quick fix to the PLC code (to deal with potential network issues--which turned out to be a really prescient decision) and then ran the test cases to verify that the thing did exactly what it was supposed to do (both nominally and in emergencies). We then spent most of the rest of the morning waiting for clearance to take our trailer out to the firing area. We were told that starting at 2pm there would be a two hour window in which we could do as many firings as we wanted to. We were hoping to get the trailer out there sufficiently before 2pm so that we could have it setup, loaded, and ready to fire as soon as the airfield was closed. We really didn't anticipate being so much further ahead of the game that we'd have time to sit around and chat.

As it is though, that was rather fortuitous, because we got to speak with some rather interesting people, such as Professor Yoshifumi Inatani of JAXA who helped manage their RVT program. He recognized the landing gear concept, was obviously flattered to hear that we borrowed our throttle control algorithm from them, and generally liked our approach. If I understood him correctly, it sounds like they are investigating another generation of RVT that has a 4-engine design similar to ours--since it allows you to have engine-out functionality (and also makes relights for landing less dicey).

Unfortunately, our preparation day didn't end up going as smoothly as we had hoped. Mostly due to the kind of logistics problems to be expected when trying to organize such a complex show with a mostly volunteer force. Simple stuff like miscommunications leading to getting the wrong size, number, and pressures for our pressurant gas cylinders. We'll just have to make sure next year that we are more thorough in our advanced coordination. In the end, due to delays waiting for people at the fueling depots, and other such, we were able to leak check our system, test the igniters, and reinsulate all the lines, but were told to clear the field before we had a chance to fire the engine even once. We really didn't want to have our first engine firing after that long of a road trip be in front of several thousand people, but we did our best with the situation we had.

That evening my parents arrived with my four youngest siblings, and the whole team ended up going out to dinner with them (along with Richard Wills, the pad manager for Armadillo's flights). The Mexican food was good, albeit a bit spicey. It was nice having them there, I was really surprised with how interested my dad was in the whole alt.space thing. He's an Electrical Engineer of sorts by training (worked at HP for 12 years or so), but apparently he had a little bit of the space bug in him after all.

Friday morning we had to be at the airport at 5am. It was cold, it was early, and we were all quite tired. It was kind of cool getting to see the Armadillo guys off from the propellant depot. Those guys are good friends of ours, and I was glad we had a chance to wish them luck. While we were chatting with them, John was mentioning the issues with his wireless communications that others have talked about, and I was rather glad that we had made the software tweak on Thursday that we did. As it is, that'll be something we'll need to make sure we deal with for next year.

After seeing them off, we were able to load up and get out to our site. We got our stuff setup, and ready to fire over an hour early, going meticulously through every possible thing on the checklist (and adding a few paranoid precautions on top of that). As it is though, we ended up waiting for over two hours from when we were ready to go to when we got the go-ahead to load LOX and light the thing off. We had been planning on doing two short firings to verify the throttle positions for our engine (and to make sure nothing was wrong), and then go on to a 30 second firing. Unfortunately, right after the two short firings, we were told to stand down for an F-117 flyby. After the flyby was over we weren't given the opportunity to finish our 5 minute session. There was also apparently some confusion on the media side, and the Jumbotron ended up looking at someone else's hardware, and apparently they had no idea that we were planning on doing to short firings first, and thought that we had had some sort of engine failure.

Fortunately, the X-Prize people got more into their stride by the afternoon. We went out, and had a picture perfect 30 second firing. I got it on video, and it was so rock-solid stable that the only clue that you weren't looking at a still photo of the shock diamonds was the slight vibration of the camera, and the violent flapping of the weeds and bushes in front of the engine. They announced it better too. We were hoping to do a quick relight after that, and do another long firing (to tank depletion--probably another 60 seconds), but one of our sensors on our stand informed us that the heat soak was bad enough that the igniter IPA valve was outside of its operating temperature, so we decided to not chance things. We don't need relight capabilities quite yet, so we hadn't gone out of our way to get higher temperature solenoid coils and plungers, but that's something we'll probably take care of before we fly anything that needs the relight capability. We'd rather have a flawless day than to push our luck in front of a crowd.

While we were up to that, there were lots of other things going on. Stuff like Rocket Belt flights, an Armadillo flight attempt, some Tripoli launches, some Rocket Truck and Rocket Bike firings, and some other flybys of various sorts. All in all a good day. Between our two firing sessions I also got to man the booth a bit. Met some commenters on the blog (including Ferris Valyn), some other bloggers (Dan Schmelzer of Carried Away), as well as several former DC-X guys. I think I also got to speak with some of Anouseh Ansari's relatives (though Robin Snelson didn't actually introduce them that way), and got to chat with some of our other friends in the industry. Didn't get to meet "Mr X" of the Chairforce Engineer blog, or Josh Gigantino, or Elon Musk. But you can't win them all I guess.

The rest of the day was a blur. I managed to pull myself away from things a bit once or twice to go look at displays, but what with being rather stressed out about our testing, I don't recall a whole bunch of it. Going all day on just one muffin and a small thing of Orange Juice probably didn't help either. My family took off early in the evening, and I think I ended up crashing out fairly early (I can't remember now).

The next day was just as early, and I was even more sleep deprived. We once again got to see the Armadillo guys off from the propellant depot area. They had managed to patch their vehicle together in time for another day worth of flight attempts. We were all pulling for them.

Things on the field went a lot smoother on Saturday. Apparently things had been figured out so that they didn't have to evacuate us off the field for every single Tripoli flight or static firing. So we got to watch some Tripoli flights from close by, as well as Armadillo's flight off in the distance. Our firing in the morning went picture perfect. We had topped the LOX tank all the way up (literally), and openned a big ol' can of hot flamey stuff. 94.3 seconds of some of the most stable hot flamey stuff I've ever seen. Ran the LOX tank all the way to depletion. It was a sight to behold. The only fly in the ointment was that when I went out to the camera, it turns out the film had run out only a few seconds before ignition! The longest firing our company has had to date, and one of our best shows yet, and the camera decides to run out of film. What are the odds?

After that firing, we got to spend a bit of time back at the booth, and checking out some of the other displays. I stopped by the Rocketplane/Kistler booth and chatted with some of the guys there a bit, visited our friends at Frontier Astronautics, chatted with Steve Harrington of Flometrics, and had a run-in with Korey Kline of eAc. He didn't believe our Isp numbers we're quoting for the engine (240-250s on the high end), and more or less questioned our integrity or competence. He said "we'll see when you actually try to fly it how much performance you really get". Indeed.

Still didn't get any lunch on Friday. Too nervous. We ended up heading out to our test site right after Armadillo flew the first leg of their third prize attempt. We didn't hear about the broken leg until afterwards. We got our test trailer setup again for firing. This time we were going to take a bit of a risk and try to do two short (3 second) firings to tune in the engine at a lower throttle setting, and then go after a 120-180 second firing if we could find a stable low throttle setting soon enough. Right as we were about to start LOX loading, Armadillo had their accident. From where we were standing we were worried they had popped another engine. We were really bummed out for those guys, and the thought hadn't sunken in yet, that that meant both prizes were going to be wide open for next year. After the fire at their site was out, and the emergency over, we went to load LOX. It turns out that the dewar didn't have quite enough left in it for a full tank of LOX this time, but we figured that'd be ok with a long half-throttle run. Who's really going to pick nits about the difference between a 150 second firing and a 180 second one?

Then we got a call from flight ops that the Masten team and the Orion team were to clear the field--the show people felt there was only enough time for one thing left, and felt the Tripoli launch would be more important. We were really crushed, but followed orders and headed back to the flight line. We were only something like 1 minute away from being able to start our routine, and the Orion guys were also only a few minutes away themselves. Ian walked off in disgust. Just when we were about to abandon hope of getting a last firing in, one of the Orion guys brought up an interesting point. Apparently their truck was loaded with Nitrous, and the detanking system for their truck was slow enough that it'd take 3 hours for them to completely safe the truck if they didn't fire. Since the truck is considered hazardous until all the oxidizer is out of it, the airfield would've been forced to remain closed for another three hours if they didn't empty the nitrous tanks the "right way". Needless to say, between that fact, and the fact that both of our teams were within 5 minutes of being able to fire our engines, we were able to persuade them to see things our way.

I ran off and grabbed Ian, and we jumped into Dave's truck as soon as the Tripoli launch was done. We raced out there, repressurized the stand, and had every ready to go within about two minutes. We decided to just bump the settings back to what we had used for the previous firings (with the LOX setting bumped down one notch since we only had a partial tank, and since the smaller helium bottles they had given us were also already at much lower pressure than we usually liked). We were informed that the Orion guys would fire first, then we would get a 15 second countdown, and then we'd get to fire. The orion truck went off right on time, and then when our time came, we pressed the button and held our breath. At least for the first few seconds--holding your breath for 74 seconds isn't highly reccomended. The X-Prize Cup guys came through in the end, and Orion and MSS delivered a grand finale.

Well, ok there was that F/18 flyby (which passed only about 50 feet directly over our heads--I'll post some pictures when I have them), but that doesn't count. It ain't a rocket.

After we packed up, and headed back to the propellant depot, I bumped into one of our friends from XCOR. Due to the helium tanks starting off so low, we ended up getting some feed-system coupling induced instability toward the end of the run. Apparently the XCOR guys had been worried that our engine was going to come apart if we didn't shut her down. When our pressurant system does it's job the engine runs just fine, but I also like knowing that we build our engines robust enough that they can take even a fairly roudy combustion instability and just keep on running. Belt/Suspenders/Duct-Tape as Randall would say.

After hauling our trailer back, offloading the propellants, and taking the trailer off of Dave's truck hitch, we headed back to speak with the Armadillo guys at their staging area. I asked Russ what had happened, and he told me about the landing gear leg breaking off, and their attempt at a return flight. I was really disappointed that they didn't manage to walk away with some prize money, but they seemed to be taking it in stride. Their flights had been amazing to watch, and for this being their first four times trying to fly the thing off the tether, and their first times trying to do horizontal translations and ground landings, I think they did fairly well. As John said, if they had had another day or two, they probably could have patched things up and pulled it off, but it looks like it'll be next year before they try again.

Randall, who had been their safety officer, looked beat. I told him that he looks like he got himself some more grey hairs this last week, and then quickly added that I think I had earned myself a few as well.

After most of the people had had a chance to congratulate John, and take pictures, I commented to John that it looks like we'd have to give him some competition this next year, and he replied "Yeah, we'll make you guys work hard for second place", and then jokingly said that he was "throwing down the gauntlet". We've got a long way to go, and only a year to do it in, but I really hope that we can be out there next year flying our vehicles too. I'm looking forward to the flyoff.

Anyhow, the rest of the evening also went pretty cool. Dave and I were with the Armadillo guys, when they let us in to take some Armadillo team pictures in front of the LEM hardware. They let us take some pictures from up close, which was kind of cool. Definitely an interesting design, though I'm sure that with 50 years of technology improvement, we could do a lot better. Alas, NASA seems not to have learned all the right lessons yet, so it may very well fall on the private sector to do the job right.

The end of the evening was a party hosted by the Space Frontier Foundation guys. I don't drink, but I figured it'd be fun to hang out with the rest of the guys anyway. At the party they announced the newly selected SFF "Advocates", and was pleasantly surprised to find that my boss Dave had been selected, as was Steve Harrington, and several others. I also found out that Ed Wright's company suffered a serious blow last week, when their camera chase plane crashed killing all 5 on board. I wanted to say something to Ed, but what can you say in a situation like that? It turns out that had he not made a last minute change in plans, he would've been on the plane that went down. That's a truly awful piece of bad luck, and I hope that Ed can recover.

Anyhow, after that and a brief meeting with the Frontier guys and the rest of our team to go over what our plans were to get this vehicle in the air, we called it a night. Sunday morning we packed out with the help of Armadillo's crane truck, and we drove the rest of the way back to Mojave that evening, arriving shortly after midnight.

Now that I'm back, we're in the process of putting together our plans for next year. Things should be rather interesting. John's team only has to make a few improvements (mostly better landing gear design) in order to have a good chance at Level One, so I hope they focus on that. It's going to be a real challenge, and the logistics side of things will need a lot of improvement, but it should be a load of fun.

18 October 2006

Setting Up At the X-Prize Cup

Well, I just wanted to drop a quick note, since I have the chance. Dave's off at some VIP function tonight, and he let me use his laptop while he was gone.

The trip down went fairly well. Ian and I left Sunday night, and camped out under the stars at Needles, CA. We then drove the rest of the way to Las Cruces, arriving early in the evening on Monday. Las Cruces is a lot prettier than I had expected, and a lot more green. There was a bit of a SNAFU with the travel agency that the X-Prize Cup guys were using to get our rooms, but the ladies at the Best Western were able to get us a place to sleep.

Dave's trip was a little more eventful. Dave headed out Monday morning with XA-0.1 sitting in the bed of his truck, and our FROTH rocket test trailer in tow. The tarps we used to protect XA-0.1 from the elements started coming off and taking parts with it by the time he reached Lancaster, so he almost had to go back and leave the vehicle there at the shop. Fortunately, he was able to find a way to get the vehicle here unscathed (basically involving taking the tarp off, and wrapping all the electrical wiring up with electrical tape). In Phoenix, while he was stopping for food somewhere, someone siphoned his truck's fuel tank. Luckily they missed just enough that he was able to make it to a gas station before the fumes gave out. He finally arrived in Las Cruces around 4AM local time, Tuesday.

On Tuesday, we were just about the only team that was there and setting things up. We were told last week that we needed to be at the airport in Las Cruces at 9AM Tuesday for a safety briefing. It turns out that we were the only ones team there, and that the real team safety briefing was Wednesday morning. We put the rest of the day to good use, but had I known that we didn't really have to be there by Tuesday morning, I probably could've driven with Tiff and the family. As it is, she won't be able to make it this year.

After the safety briefing, we had a high-lift take XA-0.1 out of Dave's truck, dropped our IPA drums off at the propellant depot, and got to work on getting the trailer ready for our firings. We decided that the best philosophy with the trailer was to trust absolutely nothing. We went back through tightening every single fitting in the trailer, and marking them all with a paint pen so we could visually inspect them for tightness in the future. We also cleaned the thing out, and ran a full click test. Tomorrow we'll leak check the thing, run the PLC test cases (to verify that we didn't do somehting with the code), and then hopefully do a short verification firing. While we were working there, Rocketplane/Kistler showed up with their vehicle mockup, and the Rocket Racing League's "Pacing Plane" was practicing its routine for the show.

There are lots of cools displays there, including a complete SSME, and part of a Lunar Excursion Module Descent Stage. I was the first one in our group to figure out what the thing was, since it didn't have its landing legs or MLI coverings on it. We thought it was a teststand till we got up close, and I noticed that one of the tanks said "Helium Descent Pressurant" or something like that. The LEM used a Supercritical Helium pressurization system that I had read a few papers about, and it's about the only rocket vehicle out there that old with a "descent system". All in all, it was rather fascinating looking over how they did the LEM and the SSME. You can learn a lot from looking at something like that when you have enough experience to know what you're looking for. I must admit that I was sorely tempted to climb under the LEM and get some pictures from the inside (as the LEMDE engine appears to have been missing from what I could tell from where I was at). Maybe I can ask one of the Northrup guys for permission....

Today, when we arrived at the safety briefings, most of the teams were there. After the meeting, we had a chance to chat with some of the Armadillo guys, since their booth is right next to ours. They brought a lot of their vehicles with them, and we had a good chance to talk shop. It's nice that our closest competitors in the VTVL world are also some of our best friends in the industry. They gave us some advice about keeping tethers from snagging on vehicle parts, while we showed off some of our engine hardware. Since our engines are regeneratively cooled (and rather robustly so), and since we use a higher chamber pressure, we can get much better performance over a much longer duration than their engines. All in all, I think both of our teams are learning a lot from each other, and we really look forward to seeing their flights. They should be a lot of fun.

After chatting with the Armadillo guys, we started trying to put the rest of XA-0.1 together for our static display. We had been waiting to reassemble the engines until we had a chance to qualify all of the subsystems, so we had a lot of parts taken off of the vehicle. Fortunately we were able to get most of them on, and the thing looks pretty good. When we're 100% done, that vehicle is going to be a rather sweet little bird. Unfortunately right in the middle of assembling that thing, we started getting rained on rather hard. It wasn't anything worse than what we've testfired our engines in (we had sleet one time, and snow another), but it really was annoying trying to work in blowing rain, and not get anything important too wet.

While we were working, we had several people come up to say hi, including George Tyson from the Orbital Commerce Project, Randall Clague from XCOR (who is safety officer on the pad for the Armadillo team this year), some of the Space Elevator guys, and several others. All in all, it was a lot of fun in spite of getting soaked through and frozen. Unfortunately Armadillo didn't get a chance to fly yet this afternoon, since the rain didn't let up yet by the time we left, but hopefully they will get a chance to do that flight tomorrow. Here's to hoping.

Anyhow, this post has been rather random, but I just wanted to let people know how things are going.

I've got those Selenian Blues

by guest blogger 'Moon' Murph

I don't try to hide the fact that it's my intention to become the most knowledgeable person of my generation with regards to the Moon. It's a great slacker goal - I come from a small demographic and have picked a relatively esoteric niche (since most of my generation is all Mars-gaga). How hard can it be? So I began building a resource base and got started on broadening and deepening my knowledge. It's an amazing subject once one begins digging into it, and one finds that all of the good ideas have already been thought of, but not necessarily all of the good ways of putting the pieces together.

This was going to be my approach for my paper "So Many Reasons the Moon" for which I submitted an abstract to ISU for their February symposium "Why the Moon?". I was going to use the "25 Good Reasons to Go To the Moon", born right here in the Selenian Boondocks, as the guiding structure. I sweated to get that puppy down to 500 words, and got the abstract in just before the deadline (like usual).

Today was the date of notification of authors. No notification. So in fine Texas tradition I've been working on a blues song...and whiskey.


My Lunar lorry broke down,
and my best girl's frown,
with the Man coming down,
I hate this lovin' crater town.

(chorus)
And just like the Earthlight
that blankets the Moon night,
I've got those Selenian Blues.

I seem to be entering into one of those quantum negative energy clusters, where all of a sudden things aren't going right in a lot of different ways. Traffic lights conspire to slow you. Special photography orders for housewarming gifts that are prepaid are not delivered on time. Work continues to be oppressive with at least one more cart of crappy loans to re-underwrite before any kind of respite. Uggh.


Meteorites don't thunder,
Confounded suit makes you blunder,
And all plans get rent asunder,
In this crappy old crater town.

(chorus)

And of course the ISDC is turning into a slog. I should be at the XPrize Cup to drum up business, with the big black cowboy hat. But I was anticipating having to pay a round trip ticket to Strasbourg, take a week of vacation, and rent a hotel room. Not easy on a cash budget since I'm finally getting the debt paid down from the disastrous aftermath of trying to parlay my ISU MSS into an industry change. Didn't happen, and I'm comfortably back in finance ensconced in an investment bank analyst/underwriter job watching the slow-motion disaster that is our economy unfold and looking for bond and loan opportunities.

But of course, it's too late now to go to New Mexico. Unless I overnight it Friday from Dallas, sleep in the car Saturday, and drive back Sunday. Uggh.


Just gotta keep trudgin',
and the future keep nudgin',
Physics won't be budgin',
in this despair-fraught Lunar town.

(chorus)

I also heard from Fisher Space Pen today, declining to buy a space in our exhibit hall. I knew that was going to be their response, as I'd talked with them at the SFF Newspace conference, but I had to try anyway. Coupled with a lot of other frustrating conference things this week it makes weigh on my mind the fact that I've been working at this for over two years now, from back when our NSS-NT chapter made the commitment to try to host one after the 2004 in OKC. They've been the one shining beacon in all of this, as we've always delivered on time and above expectations. That's why I don't need tooo much alcohol to deal with it. ;-)


Well the still went kablooie,
and the work orders're all hooey,
Ahh screw it, I say phooey,
to heck with this darned Lunar town.

(chorus)

I'll probably go to the ISU conference anyway. I do kind of miss Strasbourg, and would like to pick up a copy of Ciel & espace at the little tabac around the corner from my old apartment on rue des Drapiers. I think my strategy at this point is to look at the average age of the speakers and see where it stands. That and the number of pretty girls.

But Cool Ed's[©] is open,
Perfect Guinness[®] is foamin',
In the dark Lunar gloamin',
I love (sniff [wipe tear]) this dear Lunar town.

(chorus)

The Machiavellian twist to all of this is that as co-chair of the ISDC conference I do have considerable (but not absolute) say in the speakers and tracks. Everyone knows to back up off me when it comes to the Moon track, so I get to do pretty much whatever I want with it. I'm working with some guys over at the Moon Society on putting it together, and I made it very clear that I will get time to talk about the Moon. 1 hour, possibly in form of two half hour sessions, or half-hour with a long Q&A. I'm keeping my options open. There's just, so much, too much to talk about.

So in the end everything'll be okay. The seven months to the conference will fly by. It will be just fine no matter how much I worry about it. And after that I'll move into a house and move forward on whatever path is next to be explored.

I will be the most knowledgeable person of my generation regarding the Moon. I can afford to be patient. Besides, the Lunar Library seems to be doing okay and generating some traffic, and I'll continue to update it as I update the v1.0, the physical copies. Having access to that kind of resource base is a powerful tool in my outreach efforts. If I win the Heinlein Prize at some point I intend to write a magnum lunar opus, or at least a "Moon for Dummies" book. Perhaps a kids book as well.

Speaking of which, the holiday season is rapidly approaching, and I challenge all Selenian Boondockers to start a local "Santa Space Toy" drive in their local communities. Get other local space clubs to join in to collect space-related toys and donate them en masse to a local collection effort. If nothing else buy a bunch of "Kids to Space" books and donate those. That's how you get attention for how important all of this space stuff is for all of our futures, even the disadvantaged.

(chorus)

Whiskey-free Update 10/19:

The confirmation came today. In lieu of fame and glory I've been offered the consolation prize of a space in the Poster Session. I recall from my days at NASA Academy that this sort of thing is a big deal. 60cm wide by 170cm tall. Hmmmm...

This becomes a significantly more difficult decision.

One of my initial motivations, that of having a work of writing in print (in this case in the conference proceedings), is now no longer a possibility. There is a possibility of a 5-page description of the poster on the Conference CD-ROM which will be distributed to all the attendees.

I of course don't have access to the kind of graphics presentation capabilities that universities or corporations have. If I tried to sneak it in at work I'd get fired.

Which means ink or laserjet pages. If I had a printer. Hmmm...

It's also a hefty investment for nowhere near as compelling a return. I derive no academic or corporate (or governmental for that matter) advantage from my space activities. It all comes out of my own pocket, from vacation days to airline tickets and hotel rooms and transport and meals and sundry expenses. Money that could just as easily go towards a down payment on a house.

So why do I need to be there?
1) To promote the ISDC. The first word is International, and this would probably be my best opportunity pre-conference to liaise with the Chinese and Indian delegations to try to talk them into participating. China launches its Chang'e-1 spacecraft in April, right before the conference. It would be great to have a presentation from them on the mission.

2) If I intend to be a Moon somebody then I should probably make an appearance at this Moon-centric event that's not one of the usual conferences.

What's frustrating?
I have to confirm by Nov. 1st, before I get to see who's going to be speaking. The option here is to forego a poster opportunity to preserve the option of deciding based on who will be speaking.

Hmmm...

(chorus)

15 October 2006

Off to the X-Prize Cup

See you all there in Las Cruces. Alas, I doubt I'll have much if any opportunity to blog while I'm gone. The whole MSS crew is going to be there, along with our vehicle, and some live-fire demonstrations of our vernier engines. Should be lots of fun.

The only drag is that I'm not sure Tiff and Jonny will be able to come. We're low on money, and have a car that I wouldn't trust on that long of a round trip, especially with my wife being as far along as she is. There still may be some last minute way, but it'll be a real disappointment if they can't make it. Jonny wanted to see his "Yaddy" fire a rocket engine. Really he does...

11 October 2006

The CBO jumps into the launcher fray

by guest blogger (and Lunar Librarian) Ken


It looks like the Congressional Budget Office decided to jump into the launch vehicle fray, releasing this week a report entitled "Alternatives for Future U.S. Space-Launch Capabilities". (Hat tip to the ever dependable NASAWatch)

This study was prepared at the request of the "Ranking Member of the House Budget Committee" (googling...looks like that's John Spratt of South Carolina. I have absolutely no idea if that's of any political relevance or not). The CBO looked at six potential launch architectures, each in isolation, as if none of the other options were available to be used in a pinch (since they wouldn't be funded by Congress). These are introduced in the summary as:

1) Pure Atlas-derived. A5M+ crew/A5H+ cargo
2) Pure Delta-derived. D4M+ crew/D4H+ cargo
3) Pure Shuttle-derived. 5Shaftd crew/Side-mount cargo
4) Pure Atlas-antecedent. A5M+ crew/ASH cargo
5) pure Delta-antecedent. D4M+ crew/DSH cargo
6) Shuttle-derived Super-Heavy. 5shaft crew/SDHLV cargo

The assumed lift to LEO for each was (shuffled by capacity):

D4M+ - 18mt
A5M+ - 24 mt
5shaft - 26 mt
D4H+ - 40mt
A5H+ - 74 mt
Side-mount - 77 mt
SDHLV - 125 mt
ASH - 135 mt
DSH - 146 mt

The report then goes into a market study in Chapter 1. The main points are:
-"Current projections indicate that maximum worldwide launch capacity for payloads less than 25mt will exceed demand by up to 100% for the foreseeable future."
-U.S. supply and demand are assumed at 40% of global markets through 2010 [about where we are right now], then dropping to 35% because (a) our satellites will last longer [cough] and (b) Asian markets are expected to pick up.
-The only thing needing lift to LEO of more than 25mt for the next decade and a half is NASA's implementation of the VSE.

Here we find out that the baseline mass for the NASA Lunar program is 150mt. The explanation for this seems to digest down to the fact that Apollo lifted 140mt to LEO, we're pretty much doing the same thing, but with more crew and supplies, but lighter materials and electronics, so only a 10% increase is needed so we need, like, 154mt in LEO this time around.

The report does note that fuel represented about 75% of that 140mt, which is a key point. This also fits with a rule-of-thumb I seem to remember seeing, that it's a roughly 5:1 mass in LEO/mass on Moon ratio (or about 80% fuel).

The usual Horowitzian objections are raised to multiple launches:
-time to execute
-leakage of cryogens during those long, lonely loitering months in orbit.
-Assembly of subcomponents in orbit is Haaard.
-So's fully-automated rendezvous & docking.

The report also makes the very salient point that for future NASA MARS missions the mass in LEO requirements have ranged from 470-1500mt. So once NASA is done with the Moon they STILL have to face the task of on-orbit assembly to meet their "next" objective (which the report also notes was not a requirement set in the VSE - these guys really did try to lay out all the facts and be impartial). All NASA's doing with ESAS is pushing the learning curve farther into the future. Penny wise, pound foolish is an old folk wisdom that comes to mind.

Next up is chapter 2, which fleshes out the three primary alternatives - Atlas, Delta, Shuttle. Existing capabilities are explored, and the usual crew-rating objections are raised regarding the Atlas and Delta. Here is where we find that since six launches are needed for the 150mt requirement there's about a 10% chance of failure of any one of those missions. The implication being that if there's mission-critical components on the launch that failed, the whole mission is a loss and the successful launches have been in vain.

It's quickly realized that some kind of modifications will be necessary irrespective of the option chosen, so we then explore some of the componentry changes to the launchers, and what the resultant lift capability will be. The report is full of comparison tables and graphics, one of which looks at the recurring and unit costs of each option. For development, the non-recurring costs are assumed to be:

5shaft/Side-mount: 9.5Bn
D4M+/D4H+: 8.5Bn
A5M+/A5H+: 9.3Bn

For some reason the A5M+ needs 5.3Bn of mods versus 3.3Bn for the D4M+.

Unit costs for a 150mt Lunar mission (one launch of which is crew):
1 x 5shaft/2 x Sidemount: 2.35Bn per
1 x D4M+/4 x D4H+: 2.8Bn per
1 x A5M+/2 x A5H+: 1.6Bn per

The problem for Boeing is that the A5H+ has a 34Mt throw advantage over the D4H+, requiring 4 launches to get over the 150mt hurdle. Looked at programmatically, the report indicates 3 x D4H+ launches with a limit of 120mt in LEO.

It then looks at the big guys, the super heavies, the Magnum lift. Nebuchednazzer even. (sorry, that's a champagne joke) The SDHLV at 125mt, the DSH at 146mt and the ASH weighs in at 135mt. All are very close for the unit recurring costs, at 1.3Bn, 1.5Bn and 1.2Bn respectively.

The report rolls this up into a programmatic projection out to 2020 of the costs of NASA's implementation of the VSE, on both ambitious and less so bases. They all come out about the same, although there's a lot that can be read into what's presented.

Box 2.1 notably goes into the risks associated with developing and producing the NASA choices (since they've been harping on the Delta and Atlas shortcomings so far). These are:

-Stability control
-Large second stage powered by modified engine
-Structural integrity of 5shaft
-Organizing and executing the construction of a launch vehicle rated for manned space flight [!?!]

Appendix A looks at on-orbit assembly. It reiterates that the US has not demonstrated autonomous rendezvous & docking, and the more launches one has the greater the risk of something happening to one of them that threatens the mission.

But let's step back for a minute and remember what the report said earlier about the composition of the launches - about 75% fuel. Of course, the A5H combo seems to be on par with the NASA proposal as far as number of launches goes, so the main risk seems to lie with Boeing, which has 5 launches required. But three of those are obviously fuel, unless you're stupid enough to ship the computer boards with the fuel supply. Looking at the launch manifests again, we see:
Shuttle: 1 crew, 1 cargo & fuel, 1 fuel
Delta: 1 crew, 1 cargo & fuel, 3 fuel
Atlas: 1 crew, 1 cargo & fuel, 1 fuel

So ultimately your core risks are the same: 1 crew launch and one cargo launch that you really, really have to worry about, and then the fuel launches, which shouldn't fail but if they do...ehh. File an insurance claim and roll up the next one.

Appendix B looks at Human Safety factors. It gives us some NASA Standard acceleration limits, notes that modified EELVs likely wouldn't exceed those, and notes that Apollo 17 would have (slightly).

Appendix C lists the Considerations affecting multiple launch Lunar missions:
-Hydrogen
-Launch Cycle
-Launch Delays
-Commercial access to Delta and Atlas launch capability

Appendix D is a bunch of pretty powerpoint-ready pictures of how the vehicles evolve graphically, while Appendix E delves further into the cost estimates for the ambitious and less so approaches.

It's a pithy report and well worth the read. It does provide a balanced presentation of the options, but in an unfortunately simplified way by virtue of the "pure-" paths of the options.

When Jon and I talk about launch architectures, we talk about flexibility. Make your CEV so that it can fit on the Delta AND Atlas. Provide orbital infrastructure for Moon missions AND other things of interest. Unfortunately, that kind of chaotic complexity doesn't boil down easily into this kind of modeling, and even parametric modeling attempts at such a system would be difficult. The CBO report doesn't consider such things as launch demand from Bigelow facilities. It only looks at how NASA is implementing their vision of the Vision, and considers that Congress will only fund one launch vehicle.

Put in that light the Shuttle-derived stuff doesn't come out looking too bad, making the politically-easy-thing-to-do be support of the Shuttle jobs. Of course, a Statesman would realize that the business of America is business, and the commercial providers can take us to where we need to go, because they're going there as well.

There are certain undercurrents in the report, and Boeing seems to come off the worse for it. As an analyst, I have to read the report in the context of it having been written by a political entity. In that regard they certainly tried to be fair and balanced in what was presented, but I still feel there was some bias, and sense a bit of tension in the wording. I also have to assume that since it's related to a political entity that "there are larger forces at work here than you know". In that context I get the feeling that Boeing is being gently sidled out of the civil human spaceflight field, putting LockMart at the fore, with Boeing probably picking up defense work in return.

From a commercial standpoint, it doesn't convince me of the need for ESAS. The report clearly notes that existing manufacturing capabilities at the heavy end exceed market demands, now and until 2020. Why then would we want to develop a whole new heavier lift capability? It just doesn't follow. Also, the issue with on-orbit assembly really bugs me. The NASA plan just pushes it out into the future. We need to learn this to be commercially competitive in the future. The U.S. needs to develop it so that we can sell the products and services for a fair price to everyone else. It makes sense to deal with the issue now so that WE are the skilled ones at doing it. Starting small, with depots, free-flyers, and facilities in LEO, extending out to EML-1, extending further to the Moon, further still to NEOs, furthers yet to Mars & Beyond (Ceres here I come!). Building it piece by piece, but lots of pieces starting NOW, and often, and involving both business and government.

Conclusion: There are a lot of interesting facts, but also some limiting assumptions. Any number of conlusions can be drawn from it, as it makes no attempt to draw conclusions itself. The results are ambiguous, with a slight advantage for Lockmart, a slight disfavor to Boeing, leaving the Shuttle-derived as a nice, safe, comfortable political alternative.

NB: The views, opinions, and conclusions above are solely the product of the author, and do not necessarily (and probably don't) reflect anyone else's. Caveat emptor, you get what you pay for.

10 October 2006

Lunar Landers

Alan Boyle has a pretty good article over on Cosmic Log about the Lunar Lander Challenge as well as the Artemis Lunar Lander (aka LSAM) that NASA intends to field in the coming years. I think the fact that Northrup is sponsoring the event highlights the "furry dinosaurs" ("mammal-friendly dinosaurs" maybe?) trend I was mentioning in a previous post.

The article makes a good point about a better approach to doing lunar missions: sending both manned landers as well as resupply landers, instead of trying to do each manned mission using a single lander. The whole idea that you should design your lunar lander vehicle to also function as a 6 month hotel is kind of silly in my opinion. Transport vehicles in a pinch can serve as emergency shelters, but if you're planning on going to stay, send enough supplies to build a base camp or settlement. Along with your crew/passengers, send several landers carrying the long-duration habitats (possibly initially using Sundancer modules to provide housing before enough in-situ manufacturing has been figured out to build the rest of the structures out of local materials). Much better than trying to make each landing mission a self-contained base camp.

I'm still not a big fan of splitting the lander and ascent stages like they're planning. I'd much rather have a single-stage reusable system, as it's a lot easier to make such a system flexible, and able to benefit from future ISRU propellant supplies if they become available. Even if you're talking about staging out of L1 or L2 instead of lunar orbit, the Delta-V is only about 5km/s, which is just about the same as a round-trip from LEO to lunar orbit and back (with partial aerobraking to return to LEO instead of direct to the surface). It's a bit of a challenge, definitely tougher than what we're doing at the moment at MSS, but not unrealistic at all, especially if you use propellant combos like LOX/Kerosene, LOX/Methane, or LOX/Propane. Anyhow, I'll have to give some more of my thoughts and musings about real lunar lander design at some future date.

I also like the comment near the end:
Davis acknowledged that the teams targeting the challenge could someday be Northrop Grumman's competitors – or its partners. "What I think is really remarkable about these entrepreneurs is that they're not constrained by traditional practices," he told me. "In some sense, they don’t know what it is that they can't do."

I think this quote makes two good points. First off, there might actually be something to be gained by more traditional aerospace companies teaming up with emerging space companies for developing lunar landers. Both the dinosaurs and mammals have their strengths and weaknesses, and working together as partners might really make sense (for both parties). The second point was that "not knowing what you can't do" is often useful, because many times the "conventional wisdom" ends up becoming obsolete over time. One example of this is the fact that conventional wisdom says that deep throttling of liquid biprop engines is extremely difficult, however you'll notice that one of the problems that neither MSS or Armadillo really had was with getting the engines to throttle stably.

Anyhow, I'm rambling a bit, but I think the overall thrust of the article was good, and I really hope that these prizes end up serving as a catalyst for strengthening the emerging base of new VTVL companies, and that those companies can help establish a robust commercial lunar transportation system. Oh, and I also hope that I get to continue to get to participate in the adventure.

09 October 2006

Apogee Tugs and Cryo Transfer

About that "light blogging"...little did I know that I'd catch the bug that Jonny had, and be stuck at home with a nasty stomach flu...

Anyhow, one of the ideas that I've given a lot of thought to lately has been that of orbital cryogenic propellant transfer, and how to actually make it happen. The problem is that while there are a lot of markets that could eventually use on-orbit cryo propellant transfer eventually, when it is on the shelf, not very many of them are near-term, or low risk. The main markets I had been looking at before were for sending satellites to MEO and GEO, sending crew/cargo for NASA to Lunar orbit and beyond, and cislunar space tourism (with eventual private lunar settlement and exploitation). All of these markets are kind of long-term or uncertain though.

For reusable or expendable tugs to fly commercial satellites to MEO or GEO, you need to build up a fairly hefty track record, due to the overly conservative nature of those markets--why save $10M when you're risking a $500M bird? The DoD seems to be willing to take a lot more risks (stuff like flying TacSat on the first Falcon I flight), so they might serve as an intermediate market, but that's not too clear.

For NASA the biggest risk is political. On-orbit propellant transfer really gets rid of most of the need for Ares I and V, and makes the existing shuttle workforce obsolete. In fact, in order to gain the biggest benefit from orbital propellant transfer, they would have to scrap the Ares I and V developments, as the development cost of those systems is about $15B, and the yearly fixed operating costs is in the $2-4B range. Without killing those jobs, there's no way NASA will be able to provide enough demand to really do anything constructive on the moon. However, killing those jobs is a very politically difficult thing to do. Seeing how little cajones either side of the House or Senate have these days, it's a longshot indeed, even if it would save billions of dollars and make the VSE actually worth doing.

Cislunar space tourism (round the moon flights or visits to a Sundancer in L-1 or L-2) is rather interesting, but won't become a reality until costs come down enough that a ticket costs about the same as a ticket to ISS does today. Such tourism will rapidly drive the demand for propellant deliveries up high enough to justify a true RLV, but the market suffers from a real chicken-and-egg issue. Until costs come down far enough, there won't be enough demand. Settlement even more so.

So, I was kind of wondering if there was any realistic, near-term market that could use on-orbit cryogenic propellant transfer, and that could give the experience base to leverage those longer term markets off of. While I was thinking about this, I stumbled across an idea that Henry Spencer had discussed a few times on usenet over the years--Phil Chapman's "Apogee Tug" idea.

The Apogee Tug
The basic idea consists of a reusable tug and a dumb cargo module. The tug "lives" at a space station (Sundancer, Nautilus, ISS, doesn't matter). When a cargo launcher (or passenger/crew launcher for that matter) goes up, it places it's load into a low parking orbit (something between the 165x185km orbit used in Apollo and the 200km circular orbit often used as the baseline for performance to LEO), and provides attitude control for the short period while waiting for the tug to arrive. The tug then leaves the station, does a burn to rendezvous with the target, and then docks or berths with it. Once mated, small fuel containers launched with the cargo module pump their contents over to the tug, which then carries the cargo module (minus the now detached upper stage) up to the station. The tug transfers enough propellant to both deliver the payload to the station, as well as return the tug to the parking orbit the next time a payload comes up. If needed, the tug could be built with oversized tanks allowing it to do both up and downmass maneuvers to and from the station and parking orbit.

The interesting result you get from this idea is that most of the time, there is an actual performance benefit (in extra cargo delivered to the station) compared to not using the tug, even if you assume fairly reasonable propellant ratios and propulsion Isps. While crunching numbers, I investigated several existing US and Russian orbital boosters, including Proton, Soyuz, K-1, Falcon IX, Delta-IVM, Delta-IVH, and Atlas V 401. While all of them showed a small to moderate payload bonus over having the launch vehicle itself deliver the payload directly to station orbit, this did require a few caveats. For many of the higher performance systems (Atlas and Delta in particular), the tug propulsion system had to have as good of Isp as the upper stage they were working with, and the tug dry mass also had to be fairly low. While this is reasonable for the LOX/Kero upper stages, it might be a bit of a stretch for the LOX/LH2 upper stages (RL-10s are pretty darned efficient, and making a smaller version of them might be tough--not to mention quite expensive).

Here were some interesting observations I made based on my calculations:
  • The apogee tug is more of a benefit if the upper stage has to provide a large amount of the Earth-to-Orbit Delta-V, with the biggest benefits going to fully reusable almost SSTO stages like the K-1 OV. Russian boosters also showed more of a benefit, mostly because they tend to be a bit beefier and have a higher upper stage drymass to payload ratio. After K-1 (which had a 9-11% payload benefit), the next two biggest benefactors would be the Soyuz and the Proton, which both had something like a 1-2% direct benefit.

  • The delivered payload to station isn't tightly coupled with the drymass. For example, the theoretical numbers I used for a tug sized for the K-1 had about 200lb drymass, and about 360lb of propellant, for a delivered payload of 9855lb (compared to 8800lb without the tug). Upping the drymass of the tug to 500lb only costs about 21lb of payload. Upping it to 1000lb only drops the payload by about 62lb compared to a 200lb tug, and a ginormous 2000lb tug (at this point a gold-plated one with manned compartment, robot arm, solar panels, berthing interface, and lots of other goodies) only drops the on orbit payload by 145lb vs the 200lb drymass version. That's still over 9700lb to the station, which is still almost a 10% increase.

    This appears to be due to the fact that since the Delta-V's are so low, since the Tug is only taking the cargo one way, and since the tug hardware is left in orbit after each shot (and you only need to provide enough propellants with their transfer mechanisms to fuel the tug). Think of the tug as a reusable third stage that you don't have to haul with you. Even for a lot of the higher performance US ELVs, beefing up the tug substantially doesn't cut very far into one-way station payload

  • A corollary of the previous point is that a given tug could probably be sized for the bigger payloads, while still being able to provide a decent payload bonus for less capable boosters. This also means that it might be possible to add substantial Delta-V reserves just in case, or make the tug capable of both one-way and two-way operations. And adding enough mass to allow the thing to be manned doesn't cost you very much payload-wise.

  • Even if the tug didn't give a direct payload benefit, it saves the requirement of carrying a lot of docking specific "smarts" on the actual cargo module. The payloads can be much dumber, and easier to design, and hence much cheaper. These rendezvous and docking specific pieces of hardware cost mass and money, and when you combine that with the small payload bonus that exists for most launchers using the tug, it becomes a fairly sizeable benefit. Not having to have each cargo module or space station chunk have its own avionics suite, its own star tracker, its own RCS system and plumbing, its own AR&D hardware makes them a lot cheaper and easier to make. The actual interfaces for these dumb cargo containers could be standardized and open source.

    [Note: Pete Zaitcev points out that the term "open source" might not be the most accurate for what I meant to say. He suggests "open specification", or a couple others. Maybe "open architecture"? Freely available for download online? I guess I'm just not that savvy when it comes to IT jargon.]


  • This last point is particularly noticable for light payload systems, like many potential first generation RLVs will be. Being able to have a tug carry hundreds of pounds of good rendezvous, docking, power, and communications hardware for you could make a huge difference for say a 1-2ton to orbit RLV. Smaller RLVs are potentially cheaper to develop and operate, but tend to suffer disproportionately from systems that only scale down so far. A tug might very well make a total payload benefit of as much as 50% for such a vehicle.

  • Making a light manned version of the tug that is still capable of providing enough of a payload benefit for all potential orbital vehicles is fairly reasonable, and would eliminate the need for autonomous rendezvous and docking. Manned docking is like state of 1960s technology. We've been doing this since my dad was in elementary school, and we have a lot more experience with it (in the US) than we do for autonomous rendezvous and docking.

  • This would provide a great way to gain experience with "orbital assembly", rendezvous and docking, and cryogenic propellant transfer. The experience gained from this system would probably be 90% of the work needed to make the first orbital propellant depot possible. And once such a system is available, things get really interesting fast...

  • If you have some flights carry extra propellants which get stored at the station, you can do occasional tug flights where the payload itself doesn't provide propellants, allowing a much bigger maximum payload to be taken to the space station than would be otherwise possible. This also tends to become a larger effect the smaller the initial payload size.

Other Tug Ideas
This idea isn't particularly new or revolutionary. It was proposed as part of the original Space Transportation System (that ended up getting axed when Shuttle costs overran). The Russians have been talking about their Parom tug concept recently that they are trying to develop. It'd be good for 60 flights, and would be a great asset, even though it would probably use hypergolics (which are a lot easier to transfer than cryogenic propellants). Constellation Services International was also thinking about using a similar system, except based around using the Progress module. All of them are good ideas. Using cryo propellants would improve the efficiency a bit, and get us a lot of experience with that technology before we start trying to run our first orbital propellant depot, or trying to fuel on-orbit our first lunar transfer stage. There are plenty of ways of skinning that cat, and I may be doing some R&D on one of the more clever methods in the near future.

Especially with something like Bigelow's Sundancer module planning to go up before the end of this decade, and with NASA's need to transition to commercial ISS resupply there's a real potential near-term market that benefits from on-orbit cryogenic propellant transfer.

Just a thought.

08 October 2006

Light Blogging

Hey guys, I'm sorry the posting's been pretty light recently. It's not that I don't have much to blog about (I actually have several things I want to write about), just that I haven't much been in the mood for blogging, or have just been way too busy.

As an aside, a lot of what I've been tempted to write about lately would involve breaking my longstanding "No Politics" rule, but each time I've succesfully managed to talk myself out of it. Very few that enter that dark road of punditry ever manage to escape it's cruel clasp as it leads them down the soul-devouring road to utter Hackdom. A strange and sad place Hackdom is, where everything is black and white and there is absolutely never any uncertainty, and anyone who disagrees with you (whether you're from Left Hackdom, Right Hackdom, NeoLib Hackdom, or wherever else) is just as bad as Adolf Hitler. Therein lies madness folks. Run away while you can!

Anyhow...I'm not sure how much time or desire I'm going to have to put thoughts to screen over the next little while. My personal financial situation has been kind of depressing as of late, and that tends to take some of the will-to-blog out of a guy. The company is doing fairly well, it's just that we've been hit with a bunch of extra medical expenses over the past month or two (a black-widow bite for me on Labor Day, Tiff's surgery back in July, me chipping one tooth and then another within a one month time frame). And even though our insurance at least covered most of Tiff's surgery, the amount we still have to pay between dental stuff (which we don't have insurance for), and the spider bite and the surgery will probably come out to more than a month's pay. To make matters worse, cash has been so tight as of late that I haven't even had a chance to get the chipped teeth repaired, which means that one is well along its way to needing a root canal, which is going to drive that total up even farther...

On the plus side, as I said, the company is doing fairly well. We've been learning far more about how to design and build and control throttle valves than I ever wanted to know, but that project's finally wrapping up. We're both getting ready for our demo that we want to do there at the X-Prize cup while at the same time we're racing to get all of the rest of the vehicle work tied up so we can fly it. We'll probably have some blog posts next week on the MSS blog about how we're doing.

Unfortunately, what that all means is that between all the long hours we're working, taking care of my family, trying to figure out how to honor our financial obligations without racking up a bunch of new debt, and trying to avoid becoming yet another blogger hack, I think it'll be pretty light blogging over the next few weeks...Which if the past is any indicator of the future, probably means I'll be blogging up a storm by tomorrow. *Sigh*

Some Jonny Bloggin

I was at home from church with a little boy who's had the barfy's and the diarrhea-ys for the past day or two. He's doing a bit better, but we still figured it was probably a good idea not to have him go spread his germs with all of the other Nursery kids in our Ward. Nothing like a little work induced sleep deprivation topped with another layer of sick-little-boy induced sleep deprivation. Anyhow, I have a picture or two of little Jonny, and figured it'd be worth doing a little bit of Jonny Bloggin:

Little Boy in Big Shoes
Whatcha Doin Dad?
Meine Schatze
Little Serious Boy
Sleepin Like a Log
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