Official Armadillo Q&A thread

Ha! Well done, congratulations! Did you get a 100kft+ GPS lock? Anyway, just going up 40km and coming back down safely is one heck of an achievement.

Now to build some more and see how high a cluster of them will go. After you've written an update for the website of course .

Fantablous!

--Ralph

First: Congratulations to AA and John Carmack for the successful
ascent and return of your STIG rocket.
137,000 ft high peak-altitude is nothing to be sneezed at, since
99.9+ percent of the atmosphere was below it, and aerodynamically
it was for all intents and purposes in a hard vacuum.

Second; I know I rubbed some of you AA insiders the wrong way, and I'm sorry.
Let it be water-under-the-bridge.

Third: (a question) Now that AA has sent up a vehicle which experienced
at least a minute's worth of microgravity, will AA soon make available that valuable commodity of microgravity you now have access to? - to offer paying researchers and scientists payload-space on board the STIG?
If so, UP Aerospace will soon have competition from your company.

If 2012 is looking good for Blue Origin and Virgin Galactic, it now looks good for you too.

Congrats to Armadillo and John Carmack. They apparently have solved the problem of instability at high velocity. No doubt getting to the full altitude for space at 100 km will come in short order as well.

Bob Clark

Well, there was a bit of a roll right about when they hit the sound barrier, and also the steerable parachute system for recovery didn't quite open all the way I think. Still, those seem like solvable problems. 40km! That's really really high!

If you read the comments by armadillo over at the youtube vids, they say that the parachute opened at a higher than expected velocity and this caused some of the lines to break. That's probably why it looks like it didn't open all the way.

Regarding the roll: I wonder about the roll behavior myself. First there was this small roll when they (presumably) hit the sound barrier and then there was the fast spinning later on... was that intentional? Is Stiga's roll controlled by thrusters/fins at lower speeds and changes to spin stabilization at higher speeds?

I don't think that Stiga had any control whatsoever -- it looked like a ballistic flight to me. (secretly I am hoping that I am wrong, and posting this will encourage Armadillo to write up their report!)

It had control: a gimbaled engine and roll-control vanes (which didn't work quite as hoped, obviously). Ben is working on the report.

Would a roll like that interfere with microgravity experiments?

The roll vanes worked up to supersonic, then didn't work as expected - perhaps a control inversion due to the supersonic shock wave. I think the vanes gave up and centred themselves. They intend to move the vanes behind the fins in future versions to avoid the problem.

These launches by the suborbital companies have an importance beyond
the suborbital flights. The engines for the suborbitals are usually of
low efficiency, with chamber pressures in the range of 20 bar to 40
bar. This results in rather low efficiency, i.e., Isp, insufficient
for orbital velocities.
However, a key fact is for vacuum Isp the most important factor is
just the length of the nozzle, not the chamber pressure. As an example
the RL-10B2 hydrogen-fueled upper stage engine only has a chamber
pressure about 40 bar but because it uses a long nozzle optimized for
vacuum use, it gets a vacuum Isp of about 465 s, quite high.
Then the suborbital companies engines could have orbital Isp's with
longer nozzles. The problem is the longer nozzles give very poor
performance at sea level.
Two solutions. One is to make multi-stage vehicles.
However, another solution is to use altitude compensation methods.
This solution would make it possible for the suborbital companies to
even field low cost SSTO's.

Bob Clark

Thanks for the new update.
Fascinating reading!!!

Concerning GPS, would you consider installing Russian GLONASS as a doubler?
It seems a good idea.

And also could you create a Google Earth KMS file to see the trajectory of the rocket in 3d, please.

Ben has posted a new write up of the STIG-A launch with a fantastic 12 minute plus whole flight panoramic video and lots of pictures on the Armadillo site.

Great work and big thanks from us all.

GLONASS electronics aren't as well developed as GPS, and the accuracy isn't as good either. Right now our GPS is integrated into the IMU, which is handy; if they had a dual system we'd consider it but I'd rather not be dependent on the Russians.

I already created a KML file of the trajectory, I have one for all three of our flights at Spaceport America. It's pretty cool.

haha:) as a russian its funny to read that you'd better not depend on russians
are you serious? )

GLONASS signal will not make you dependent in any way
its could be a very useful safety measure
and btw you are a little misinformed about GLONASS (electronics and precision)

ok... im not gonna advertise here anything . i just thought its wise to use both systems.