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Linux Rocket Blasts Off This Fall
HardcoreGamer writes "An Oregon amateur rocket group, the Portland State Aerospace Society, plans to launch a Linux-powered rocket weighing 12 pounds to 55,000 feet at a speed of Mach 3 in September, Wired News reports. The rocket's onboard computer is an AMD 586 processor and a Jumptec MOPS/520 PC/104+ board along with a power supply, a PCMCIA card carrier for an 802.11b card to transmit data to the ground, and a carrier board for a 128-MB CompactFlash card for long-term storage. The flight computer runs a stripped-down version of Debian Linux, with the 2.4.20 Linux kernel. The group will present a paper (HTML | PDF ) on the use of free software in rocketry at Usenix 2003. The real question is whether their network card will survive 10 seconds at 15 Gs!"
I was wondering about that, too. But the site states that they're allowed to boost the power legally if it's operated by a licensed Ham radio operator (under FCC Part 97 rules).
Cringely got something like 10Km with a Pringles can, so I expect someone with more of a clue can push that to 55,000'.
k.
"In spite of everything, I still believe that people are really good at heart." - Anne Frank
http://www.computerworld.com/mobiletopics/mobile/s tory/0,10801,75830,00.html
Someone's done a 72-mile link.
The hard part is that you either have to track the rocket with a directional antenna, or try to make everything work with a non-directional antenna. The 72-mile link was from one fixed point to another using mid-size parabolic antennas.
I would expect that the guidance systems for most rockets built in recent years would use a real-time OS like QNX or Chorus, not Linux.
Never eat more than you can lift -- Miss Piggy
For the longest time the software was written by hand from the metal up. You can't afford to have one bug in space code. It could cost half a billion dollars. Every routine was coded three different ways, and three systems ran separately. If they ever disagreed you knew you had a problem. So while you have an OS of sorts, it's the Shuttle OS, and nothing else. After all, there are a thousand assumptions that OS developers make that a space programmer has to choose him or herself. In Linux, the coder is always saying "this amount of precision is ok," but for a rocket the amount of precision needed is very well known, and incredibly demanding at all levels. For a hobbyist group, linux is one thing, but if you want to put something in geosynchronous orbit indefinitely...
There's an explanation of how they intend to achieve this on the site, along with a link to a news release that cites the Swedish Space Corporation's success transmitting data over 310 kilometers using 802.11b.
http://cvs.psas.pdx.edu - Have fun!
... have been doing this for awhile. The PC104 stack in their VTVL rockets/crafts have always been linux kernels.
He's also been using 802.11 for communications.
His laptop control station is win32 though.
ArmadilloAerospace
-malakai
-Malakai
A Dragon Lives in my Garage
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They also have to comply with U.S. export laws (International Traffic in Arms Regulations, 22 CFR 120-130) that require an export license for missile technology. That trumps the GPL. You can get in serious trouble if you ignore the law.
Mea navis aericumbens anguillis abundat
I think a bigger concern would be whether the connectors are properly held together and maintain electrical connection. The boards should be fine.
You can find lots of DEBI info by looking through the past two weeks of my journal. You'd have to follow links from my web page link below in my sig. I won't link it directly since the machine will probably tank after only a few concurrent connections.
We're currently using a cylindrical patch antenna on the rocket, and a semi-directional antenna (helical) on the ground. Eventually, we'll build a tracking dish for the ground, and try to phase the rocket antenna to get the antenna pattern to point more down. Right now the rocket antenna pattern is a sort of "donut", which is fairly suboptimal.
Microwave antenna design is hard. If any gurus want to contribute expertise, please drop PSAS a note.
I though the first linux powered rocket took flight 2 years ago...
I remember they used the jumptec 386 dimmpc and used ham radio packet on 144/440mhz to get telemetry up/down.
I know I saw it here. Can anyone find it?
Do not look at laser with remaining good eye.
Mach 3 is about 833m/s.
f = 2.4GHz*(1-833/300000000) = 2.399994GHz
Thus the frequency changes by 6kHz.
Hams are not allowed to transmit music via a phone mode, i.e. J3E, A3E, F3E, etc. Digital music (and pictures, for that matter), as long they are not facilitating anyone's regular business, are fine. I can legally stream my MP3's via amateur radio all day long (with proper ID, frequency and mode selelection, and station control, of course). The data is not encrypted, it is encoded and compressed - perfectly legal. Bits is bits, I always say.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
I could imagine a 2.4GHz 'stripline' loop (or semi-loop) yagi made of copper tape glued to the outside of your body tube. Naturally the reflector(s) would be up, and the directors down. This would be fairly directional, depending on the number of elements.
Alternatively, wrap the copper tape helically around the body tube, matching the sense of your ground antenna.
Good luck!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
http://www.space-rockets.com/congress