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Armadillo Aerospace: Space Access, Improvements, Module Work

Published by Sigurd De Keyser on Mon May 7, 2007 10:03 pm
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Armadillo Aerospace: Sorry about the missed update last month, I was doing one of my “working retreats” for Id, where I lock myself in an empty hotel room with a computer to get a lot of uninterrupted work done, and I didn’t work my way out from under the backlog pileup until half way through the month. I was still having trouble getting this one done now…

Matt set up a cafepress shop for Armadillo, so you can now get t-shirts again, as well as all the other various cafepress items. A t-shirt probably pays for a few gallons of rocket propellant. :)

Space Access

Space Access ’07 was enjoyable, as always. Matt had time this year to get another Armadillo progress video together that covers the last two years of work:


This year was particularly interesting due to the many Lunar Lander Challenge entrants present. Despite there being nine teams registered for the Lunar Lander Challenge (up from four last year), I still think there is a very good chance that we will be the only competitors flying at the event. There is a lot to be done. However, there are several entrants that are very serious, and have all the resources necessary to reach the goals, if not, perhaps, in time for this year’s event.

While much smaller in scope and grandeur, in some ways the LLC is turning out more productive than the X-Prize. Despite some incorrectly reported figures in the media, there wasn’t very broad development expenditure for the X-Prize. Rutan reportedly spent over $20 million, and I spend about $1.5 million, but I doubt all the other teams put together actually spent more than $1 million in cold cash. Sweat labor counts, but it obviously didn’t cut it. All of the serious LLC teams are planning to spend six figures in cash, as well as all the labor, making it much broader based and more competitive. I also think that the more open nature of most of the competitors is a very positive thing, and I like to believe that the Armadillo example has had something to do with it.

Masten Space Systems
The Masten guys are almost certainly the closest to getting another vehicle flying, but their prototype vehicle won’t be capable of competing, so they will need to build a brand new vehicle in the next few months. Dave commented at the conference that they thought they were two weeks away from flying the vehicle, but they had thought the exact same thing back in October. Another month and a half has gone by since he said that…

Paragon Labs
Kevin Sagis and I have been trading email for a while now, and I have been really impressed. They have the best fabrication facilities of any of the teams (better than us), and they have experience with solid rocket powered attempted space shots, so they know how to do field ops and deal with the FAA. Also as a very positive sign, Kevin was still uncertain at SA whether he would actually enter, because he knew how much work actually needed to be done, and wasn’t positive that they could make it. A realistic grasp of the effort required is very valuable.

Speed Up
I love the “rocket jet ski” approach for a commercial direction, and I hope they can pull it off. It has almost all the risk of suborbital flight for a fraction of the profit, so it is a gutsier play, but Bob seems to be willing to have a go at it. Sitting around at night after the sessions, Bob, the Frontier guys (who are actually building the vehicles) and I were talking about how cool it would be, and someone said something along the lines of “Its Wyoming! We could put guns on it!” Kidding. Mostly. J Being peroxide monopropellant based is the only chance a brand new, from-scratch entrant really has to make it this year. It really does make things a lot easier. We sold them one of our old fiberglass peroxide tanks a little while ago, so it would be quite ironic if they managed to somehow snag first place at the level one prize away from us.

Unreasonable Rocket
I have always said that anything that we have done at Armadillo could also be done for a quarter of our expenses if someone actually tried to minimize cost in all ways. Paul Breed Sr. and Jr. are going to try and verify that. However, there was always a caveat to my statement – it will take longer. I don’t think they can do it in time for this year. You can’t help but pull for a father and son rocket team, though.

SBIR Award

Somewhat to our surprise, Armadillo was awarded an Air Force SBIR contract. We made a fairly general pitch about the virtues of a modular space launch system built in our current style, and apparently they liked what they saw. The fact that the two awards made for this round were to Armadillo and XCOR seems to make the point that they want to get something that actually flies. While phase I awards are really just for studies, we will be generating a lot of flight and operational data from the module work we were already doing. If they decide to go forward with a phase II contract, we will deliver some vehicles that they can actually USE.

I am of somewhat mixed opinions about SBIR work. In many ways they are sort of “life support for small aerospace companies”, and I believe that many companies get stuck in that rut, desperate for a tiny contract so they can keep the lights on and their people employed, and they never make any real progress. Commercial work is preferable in a lot of ways, but I don’t have nay personal issues with having the government as a customer. We are going to do our best to deliver real value for them, rather than just trying to efficiently suck out some funding.

Neil is our point man for this effort, and he starts working full time again this month. In addition to managing the SBIR work, he is also busy preparing an experimental launch permit for the modular vehicles, and we will be putting in for a full launch license later this year. His day looks a lot more like “real work” than the “playing with rockets” that the rest of us do. Our various permits will be:

Experimental permit #2 (granted): dedicated for the Quad flights at XPC ’06, now useless
Experimental permit #3 (granted): initially for Quad flights at the Oklahoma spaceport, will get an addendum for Quad flights at XPC ’07.
Experimental permit #??? : Single module flights at Oklahoma and XPC ’07, hopefully also covering two and four module flights at Oklahoma and Spaceport America.
Launch License #??? : commercial revenue flights of one / two / four modules at Spaceport America.

Various Improvements

We are continuing to work on various improvements to our flight operations.

We currently use a fairly high flow electric pump to load alcohol into the rockets, but we are testing a pressure loading option to shave a few minutes off of the loading time. This would add an operation to load the alcohol from the drums into the pressure tanks at the fuel depot, but it saves prize clock time during operations.

Matt and Phil have done a nice job integrating all the receivers, signal conditioners, screen dividers, camcorders, and monitors for the three camera video feeds coming from the vehicle into a single box with a single cord. We did find that the signal conditioners have some heat issues if they are left on for several hours at a time.


We had made a portable pole mount for our telemetry radio, but lately all of our flying has been done with the control vehicle parked on asphalt, so Tommy made a support box that lets us conveniently stick the Esteem telemetry radio on top of my car. Using power-over-ethernet is convenient for this.


I finally converted one of our electronics boxes over to lithium ion and lithium polymer batteries, which saved 18 pounds. We have always used very large batteries for the main computer, because it is a big benefit to be able to leave the computer on essentially all day without having it run down.

We are going to try using some lighter weight landing legs that are basically just leather covered foam pads. They can’t break, but the landing shock will be greater. The trade off is that they are over 20 pounds lighter than the super-reinforced shock based ones we tested a couple months ago.


We made a nice new program to mill our igniter / engine mount pegs, which we used to do mostly by hand. We need to build at least seven engines to have the latest designs on Pixel, Texel, and the five modules under construction, so manufacturability is a big issue for us. We included pre-drilled metering orifices where the AN fittings for lox and fuel get welded on, so we no longer need to use NOS metering jets on a cut down AN fitting. Russ added engraved lettering, so nobody has to wonder which one is which.


Our last attempt to fly a 180 second flight has a bit of a bang on startup at the higher initial feed pressure, and we found that we had cracked the graphite chamber (it still flew for two minutes before I shut it down). To get more immediate ignition, we changed from a single downward pointing igniter throat to four angled throats that throw a flame jet more directly under the main injector elements.

Also after that last flight we found the bottom plate of the engine slightly bowed out, so we decided to go ahead and finish the redesign of our engine chamber that we had been planning for the modular vehicles. The new design uses a big Smalley snap ring to retain the injector instead of a flange, and moves the fuel distribution manifold inside the tube instead of outside, with the graphite chamber stepped down to make room for it. This was seven pounds lighter than the old engine, but more importantly it is easier to manufacture consistently. We are also using a Helicoflex metal seal instead of an o-ring at the injector, to avoid the o-ring erosion we were seeing with Viton.


One thing that we should have started doing a long time ago is hydrostatically proof testing our engines to well above the operating pressure. When we took the first in-tube engine up to 500 psi, the top closure bent a whole lot more than we expected, so we redesigned it with a thicker plate.

Using the new engine, we did three 100+ second flights in a row yesterday with everything working well, in full LLC trim with payload and operating gold box. Each flight took a little less than an hour, and we weren’t hurrying at all, so I think we are in good shape for the contest time. We put in a request to do untethered free flights at the Oklahoma Spaceport next weekend, but the FAA is insisting on two weeks prior notice to use our permit, which seems excessive and annoying. We are now requesting permitted flights every single weekend for the rest of the year, which is probably not exactly what they wanted. We are going to try and go the following weekend, but the weekend after that is killed by the ISDC conference (come see Pixel and meet some of the Armadillo crew if you are in the area) and a meeting of the Personal Spaceflight Federation.

I expect that by the next update we will have full video of us essentially “winning” the level 1 LLC. We have every reason to believe that the new engine will handle level 2 as well. We get 120 seconds of flight with a half propellant load, so 180+ seconds should be easy with the full load, especially since the engine will be operating at a higher pressure while burning all the extra propellant. We have had something or another go wrong on each of our four attempts at 180 seconds so far, but the vehicle is getting better all the time.

Module Work

Module #1 is close to ready for hover testing. James has been doing a lot of work preparing for production of these. We have a jig structure that encloses the entire vehicle to guarantee that the inter-module links, engine mount, and computer mount are all square and at the right location.
http://media.armadilloaerospace.com/2007_05_02/assembled.jpg (we missed getting a picture of it with the engine and everything else on)

Assembly went fine with our concentric tube design. The lower (lox) tank has a 2.5” ID pipe going through it with a metal bellows at the top to keep it from being stressed. The upper tank has a 2” OD tube with 1/8” thick o-rings centering it going all the way through the bottom tank and hanging free at the base. We have about a half hour before the alcohol starts freezing in the pipe across the air-gap. With an ambient pressure air gap always between the fluids, we don’t feel that it has the dangers of a common bulkhead or conventional internal feed tube, and the assembly is quite elegant. Better pictures next update.

The legs have been a pretty big hassle to get right, but they are almost done. The legs bolt on to the inter-module mount points, but we want to be able to transport assembled single modules, so the spread of the legs must fit within the DOT 102” maximum vehicle width. The legs are fairly heavy, but we want to be able to use them on four module systems, and the single module has plenty of margin for 90 second level 1 LLC flights, so we aren’t sweating it much. We can make them with carbon fiber tubes if we wind up needing higher performance.

We fabricated bolt-on pegs for our elevated tether testing, which bolt opposite the upper leg mount at the module connecting blocks:

We have plenty of Aspen Aerogel insulation for all the modules and lots left over for patches:

BTW, congrats to the Up Aerospace guys for a successful space shot in New Mexico!

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