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Carmack's Armadillo Aerospace Rocket Crashes and Burns
mcgrew (sm62704) writes "New Scientist is reporting that John Carmack's 'Armadillo Aerospace' has suffered a large setback in the Northrop Grumman Lunar Lander Challenge after one of its two main rockets crashed and burned. 'During the test, Texel lifted off and hovered without incident, then descended again and touched the ground. But it then rose again unexpectedly and began accelerating upward. "Crap, it's going to fly into the crane, I need to kill it," Carmack recalls thinking. He hit the manual shutdown switch, turning off the vehicle's engine in mid-flight. Texel was about 6 metres above the ground and fell like a stone. One of its fuel tanks broke open when it hit the ground, spewing fuel that ignited and engulfed the vehicle in flames. "It made a fireball that would make any Hollywood movie proud," Carmack says.' No one was hurt in the crash, but the vehicle was destroyed."
It was a bad weekend for Armadillo. We set out to put some flights on Texel, the backup Quad vehicle, and it didn't go so well. We have video that we will be releasing, but Matt had to leave for Germany the next day, so it won't be digitized for a week and a half.
We started out with a normal 90 second elevated / tethered hover test, but we ran into a problem with the actuator power. We initially thought it was a bad main power switch, but it turned out to be the lithium-polymer battery pack cutoff circuit incorrectly shutting down at 16 amps of load instead of 40. This was a new battery pack ( www.batteryspace.com HPL-8059156-4S-WR), and it had passed all the individual actuator checks, but when the igniter started firing with both high amp NOS solenoids, the battery shut down (went to 0.3 volts indicated) after one second and stayed there until it was physically disconnected. Russ made a fairly heroic field repair, cutting open the battery pack and wiring around the protection circuit while sitting on top of the rocket. The total time spent on this after three attempts was 90 minutes, and enough lox had boiled off that the vehicle hit lox depletion at 60 seconds of flight. We got a few good data points from this: the batteries need to be checked at full current load, with vents open we boil off about two pounds of lox a minute, and lox-depletion runs are benign, if a little flamey.
For the second flight we were going to do a ground liftoff (still tethered for runaway protection) to test the automatic ground contact engine shutoff code. We have had several reasons to want to automate this: We get a fair bit of bounce on touchdown, because the engine is essentially keeping the vehicle weightless during the terminal descent. A computer controlled shutdown would be at least a half second faster than my manual punching of the shutdown when I visually see ground contact. The quads will just safely bounce around on the ground a bit if the engine just goes to idle and doesn't shut down, but the module, with the gimbal below the CG, will try to tip itself over when a landing leg becomes a pivot point, so there is extra incentive to get it shut off fast. You can see that in our XPC '05 vehicle flight. We also need to handle the case of the vehicle landing in a situation where I can't shut the engine off promptly, either because there was a telemetry problem, or when we are doing high altitude flights, it lands out of direct sight. There is a separate shutdownTime parameter that will keep it from sitting there at idle for ten minutes, but a telemetry abort could still have it on the ground and cooking for the better part of 220 seconds. We could still shut the flight safety fuel valve, which would result in just idle level lox pouring out of the engine, but that has its own problems.
I have been very hesitant to put in ground contact shutoff code, because shutting the engine down for some incorrect reason would be catastrophic, and I would feel awful if that ever happened. We had some switch based ground contact sensors on the old VDR, but they never got tested. We have concluded that the landing jolt, as seen by the IMU accelerometers, is a good enough ground contact signal. There is always the worry that combustion instability, or a nozzle ejection event, might trigger the signal level, so there are additional guards about it only functioning when you are within three meters of the ground (we must leave some slop for uneven terrain or GPS innacuracy) and trying to descend.
We loaded up again, being very thankful that we now pack three six-packs of helium for each test trip after we were forced to cancel the second flight on a previous test session due to insufficient helium after troubleshooting a problem forced a repressurization on the first flight. Liftoff and hover was fine, and at the 45 second mark (no sense pushing it on a ground liftoff), I had it come in for a landing. It hit the ground, and I saw it bounce back up. My first thought was "That didn't seem to help at all".
Sometimes it's best to just let stupid people be stupid.
From John's post to the Amateur Rocketry list :
We have video that we will be releasing, but Matt had to leave for Germany the next day, so it won't be digitized for a week and a half.
So, it's coming, just not released yet.
XenoPhage
Technological Musings
Carmack and Romero are two different people.
Failed? I think not. Just so you're aware, Armadillo was the only team last year to even attempt the lunar lander prize, and except for some bad luck, would have walked away with it.
This year, there may be a few other challengers, but I think John and company will walk away with it. John and his team have taken this challenge in directions that the "big guys" have never tried, and it's working.
We'll see! Only 65 days left!
XenoPhage
Technological Musings
This was how soviet was testing their rockets, by trial and error. They launched a prototype and then they looked how it flew and why it blew up if it did. Saw a documentary about soviet rocket engineering and in it some nasa guys said it was one of the mayor reasons why soviet was greatly ahead of USA in rockets.
Texel was one of two essentially identical vehicles that Armadillo put together last year for the Lunar Lander Challenge. The other is Pixel, which is the one they actually flew last year (and that had a good shot at winning) at the LLC level 1 event. Pixel is still flightworthy. This crash of Texel doesn't take them out of the LLC race, although it will lower their chances of success; it is going to make them much more cautious about banging Pixel up ahead of the next LLC competition and therefore they'll get flight less testing in.
They're also working on a set of new vehicles they call Modules, of which I gather they have one essentially complete and five in production.
With reasonable men I will reason; with humane men I will plead; but to tyrants I will give no quarter. -- William Lloyd
If they performed slow re-entry (ex: SpaceShip One), then one of their two failures would not have occurred as the heat would not have built up.
SpaceShip One is sub-orbital with a maximum speed of about Mach 3. I don't understand how you can compare the two. A "slow" re-entry would require a whole lot of fuel to slow the vehicle down from orbital velocity to a safe entry velocity. Fuel you would have to launch with. You'd have to burn the fuel relatively quickly to ensure you don't enter a highly eccentric orbit that intersects with the atmosphere before you've finished your maneuver. If anything goes wrong here, you're toast. You'll burn up in the atmosphere.
Education is a better safeguard of liberty than a standing army.
Edward Everett (1794 - 1865)
Quote: Or take shuttle. It was designed on paper, and the very first hardware iteration was declared operational configuration.
/. crowd isn't either, but IIRC, the Space Shuttle was preceded by a lot of hardware developed to test ideas and concepts that were milestones to the Space Shuttle as we know it today. Remember the X-15 rocket plane? Or how about the lifting body airplanes of the late '60s (?) and '70s -- you know, like the one that crashed and burned during the opening credits of "The Six Million Dollar Man" (really dating myself now). Second, the Shuttle *was* tested and redesigned during it's lifetime. The original Shuttle, the Enterprise, was essentially a proof-of-concept vehicle. Again, I'm just barely old enough to remember (I think I was 7 or so when it first flew) so I might be a little off on the details, but as I recall, it was flown to altitude on a 747, then released to glide back to a landing at...Edwards AFB?...several times, and the data collected resulted in modifications to the design before the first production Shuttle ever flew. Then there was the SRB redesign in the wake of the Challenger, and more recently, the external tank modifications after the Columbia disaster. So while I'll admit that the Space Shuttle itself was the first and only version of a reusable launch vehicle, I don't think it's entirely accurate to say that the Shuttle was designed and built in a single iteration.
Ummmm....not exactly. First, I'm just barely old enough to remember a lot of this, so no doubt a lot of the
Nevertheless, your point about the approach taken by Armadillo Aerospace and the like is entirely accurate -- it's an evolutionary approach with a lot of iterations. There's still a long ways to go before commercial orbital and suborbital flights are as common as airline traffic is today.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
You see, we're all volunteers at Armadillo, and therefore all have day jobs. My day job required me to come to Germany for the Leipzig Games Convention to promote things entirely unrelated to Armadillo. This is the job that actually provides a salary, so it kind of takes precedence over Armadillo sometimes.
Could I have left the video with the others so that they could capture it and get it up on the web page? Well, no one else on the team has any experience with that -- their expertise is in software design, electronics, manufacturing, welding, etc. So I'd have had to train them to do it. And again, why would I do that when, as I understood it, John's not going to post the video till the next update anyway?
But you go and believe whatever you want. Just know that we WILL post the video when I get back.
Matthew Ross
Armadillo Aerospace