X-Prize cup 2007, a test for reusable rocketry

Well, as has been noted in the newspace circles, Armadillo Aerospace failed to win the lunar lander challenge even after coming very close in 2006 already, and being even closer this time. Their report text is here and videos and pictures here (highly recommended). Other teams failed even to participate.

Everybody was cheering for Armadillo. The dream carries on. More testing, more steady state solutions. One part of Armadillo’s problems has been that they have to drive quite a distance to their test site, which limits testing a lot. Teams like Masten Space Systems have it easier in Mojave, but they had some tank supplier problems as well as some things with the control algorithms, and haven’t done any info updates for over a month since they started trying to do hover tests. (Wink, wink. :) )

Acuity and Paragon were teams that didn’t give much info, so it was hard to judge where they were, the same applied to BonNova. Speedup gave some info as well as Micro-Space. Unreasonable Rocket‘s Paul Breed was very informative in his blog and I laud his efforts.

One thing which some parallels can be drawn to is the DARPA Grand Challenge, which promised prizes to teams constructing an autonomous vehicle that can drive from Los Angeles to Las Vegas via a marked desert route. The first year was a failure, with most of the teams failing to even qualify for start. (There was a short obstacle course test.) But the next year, the prize was won and many vehicles finished. It seems that either the Lunar Lander Challenge is harder or then people are not willing to put similar broad resources behind it. It may be both. In 2007 the DARPA Grand Challenge has moved to a new urban setting.

There also exists a different comparison. The X-Prize, which was won by Scaled Composites in 2004. Other teams didn’t come even close or even make that much progress and almost all disappeared quickly after the victory. Scaled had a big money backer, Paul Allen, and worked long and hard to do it. A very different picture from the Grand Challenge contest, as well as a different style of doing it. One worked with yearly races with increasing prize money, the other was an absolute deadline. And of course the former was probably much easier than the latter.

There are many ways Armadillo’s failures can be analyzed. You can look at subsystems: this year their problem was the engine (you can read the details in their report mentioned above). Last year it was the landing gear as well as a badly surveyed track.

But the engine problems had some story behind them: either the air was more humid or the altitude was higher than on their own test site. Or the ethanol composition was different which caused clogging of the injector, which caused grief later. Or they hadn’t run back to back flights so close after each other with the engine before. This all speaks of how the small details are important. Jon Goff (who inhabits my blogroll) has said how they at Masten Space had the first engine hard start problems only on the 30th 300th test run. You need lots of testing to make designs reliable (or then somebody invents a foolproof way to do a start). Some people have also proposed that since the development of new reliable rocket hardware takes significant time and effort, it would be easier to buy ready made engines from subcontractors. But it seems this has not caught on, the lunar lander challenge outfits are so poor that they can’t afford this and have to develop their own stuff. Also you lose intellectual capital and technological lead distance by selling your engine design. And lastly, people saw what happened to Masten when they subcontracted their control algorithm (or at least assume until they do a development update). It’s a bit harder to troubleshoot when you didn’t make it yourself. Although the decision still might have sped up development considerably.

It’s an interesting juncture. If there is no more than one LLC competitor next year or even if there are but the prize still isn’t won, would a rethought approach to the problem be better? On the other hand, with a tiny bit more luck, Armadillo could have taken the money home already in 2006, and people would have made other far reaching conclusions about these things. It’s not wise to try to make up your mind from too little data and proclaim somethind far reaching. So I’ll make a prediction, like last year: next year Armadillo will finish the challenge and there will be other competitors too.

Of course, if someone wanted to enter the suborbital business, they could hire me as a consultant and I’d say which parts to buy from where to combine into a perfect vehicle. ;)

Edit 2007/11/5 : Corrected Masten’s 30 test runs before the hard start to 300, per Jon Goff’s comments. :)   He also says my guesses about their control system are not entirely right.

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4 Responses to X-Prize cup 2007, a test for reusable rocketry

  1. Gravityloss,
    One quick correction. Our first hard start was after about 300-350 runs, not thirty. By that time we had tested at two different test sites with drastically different climates, we had tested in rain, sleet, snow, and dust storms. Our two sites had substantially different altitudes, etc. But the problem wasn’t related to any of that. It turned out to be a marginal igniter interlock design. It worked fine most of the time, but every once in a while the igniter would be strong enough to trip the ignition detection system, without actually being strong enough to light the engine fast enough to avoid an overpressure. It took us another 50 firings to reduplicate the incident and get enough data to really solve the problem (we had originally thought it was a stuck LOX valve). Since then we’ve had 300 more firings (at least), without any repeat of the hard start. But even then we still find new issues and squawks from time to time.

    People that test an engine one or two dozen times and think it’s reliable are being a bit naive.

    As for control algorithm issues, it’s not exactly what you think. Hopefully we’ll be posting a long update soon. We’re a bit past due for one, aren’t we? :-)

  2. gravityloss says:

    Thanks for the correction and insight, I edited the original post. :)
    And yeah, I hope you’ll do an update soon. I’m especially interested in the control system stuff as it’s something I plan on working with on my own since without the resources of a full blown rocket garage, propulsion is kinda hard. :)

  3. James Kempf says:

    The analogy with the Darpa Grand Challenge occured to me also. It is interesting comparing the two, in particular, how different the general background of the competing teams is. The Grand Challenge consists mostly of university teams with sponsoring by car companies. The Lunar Lander Challenge consists mainly of small startup companies which, with the exception of Armadillo, are financially somewhat marginal. In one case (Paul Breed’s Unreasonable Rocket team), it is basically a guy and his son. There were something like 20 teams in the Grand Challenge, only one ended up competing in the Lunar Lander Challenge.

    This comparison is not to denigate the teams seeking to compete in the Lunar Lander Challenge, they are all dedicated and their ability to make progress with very limited resources is astonishing. I am a great fan of Paul’s blog and the Armadillo updates, and I wish them both the best of success in the next round, and Masten also. I also wish Masten would be more forthcoming about their technical progress, but I assume they have their reasons for not publishing more.

    I think the comparison says more about the sad state of research on rocketry than about the competence or ability of the teams, to say nothing of the difficulty of the challenge. Imagine if Lockmart or Boeing were to sponser a university team to compete in the Lunar Lander Challenge the way GM and Volkswagen did for the Grand Challenge, for the win (CMU) and show (Stanford) entries. The teams could benefit enormously from the internal technical knowledge of these companies, to say nothing of the financial resources, such a sponsorship would provide.

    I don’t quite understand why this is so, one reason perhaps is that universities in this country don’t seem to do much hands on research in rocketry anymore, though there does seem to be quite a bit of work on computational fluid dynamics for things like pulse detonation engines, hypersonics, and the like, with an occasional subscale demo thrown in if NASA funding becomes available. But research on the system problems of building reliable, reusable rocket vehicles seems completely uninteresting. In other areas of technology, real breakthroughs in research often come from universities, even when small startups ultimately end up commercializing the technology. I wonder if there is something in the nature of the problem that makes this pattern different for rocket vehicle/systems.

  4. Jonathan Goff says:

    James,
    I wonder if there is something in the nature of the problem that makes this pattern different for rocket vehicle/systems.

    My guess would be that automobiles have a large and growing market, whereas large rocket systems have almost always been financially losing (or marginal at best) propositions. If we got to a point again where there was significantly growing demand and growing capacity for rocket systems, I think you’d see more university research being pulled in. But as it is right now, the market’s fairly stagnant.

    ~Jon

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