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Oscar-40 Ham Satellite Transmitting Again
Bruce Perens K6BP writes: "The Phase 3-D Amateur satellite, called "Oscar 40" now that it is in orbit, is back on the air. A ground station sent a reset command and a command to turn on a microwave transmitter, which worked on the first attempt. The transmitter is sending an unmodulated carrier until telemetry software is reloaded, but it's clear from the doppler shift of the signal and the loss-of-signal time as the transmitter crosses the horizon that the signal is coming from the satellite's orbit. The ground controller will now reload the flight computer software and bootstrap the main flight computer. It will take a while to reload both computers and to investigate problems with the satellite, as this is complicated by the attitude and orbit of the satellite - right now it's not actively stabilized and is only pointing the antennas toward the Earth during part of its orbit, and of course it's only above the horizon from any ground controller's perspective during part of each orbit." Read on for a bit more on this promising news."
"A board of inquiry will convene to investigate the loss-of-signal incident and to change procedures to avoid another such incident with this or a future Amateur satellite. General information about the satellite can be found at www.amsat.org. The following announcement is from www.amsat-dl.org:
The Santa Claus brought AO40 back On Air! At 2000-12-25 21:45 command station Ian, ZL1AOX sent a RESET command through L-band and an initialization block to switch the S2 S-Band transmitter On. Just after the first attempt the S2 beacon came on 2401.305 MHz, Signal was about S5 to 6 which was comparable to when S2 was heard last during testing The S2 beacon produced a steady signal and from the doppler wobbling it is also clear that it is in fact coming from AO-40. Ian ZL1AOX reported that he was able to copy and observe (with Spectrogram) the S2 beacon. His LOS time was 2000-12-26 03:45:15. Predicted LOS from NORAD set #12 keps gave 5 secs later. Approx distance was 61,470 Kms. Today, 2000-12-26 at about 16:05 UTC, ZL1AOX will acquire AO-40 shortly after perigee with a reasonably good squint angle. He will than start reloading the IPS software. Until than the beacon will not carry any telemetry, just a carrier. Once the bootloader for IPS is up, you will see "X" blocks in the telemetry until IPS is completely loaded... (Thanks to DB2OS for this information)."
Thanks
Bruce
Bruce Perens.
Thanks
Bruce
Bruce Perens.
The HAM (Amateur radio) community. Has a long history of building its own satellites. They are put in orbit by NASA on rockets that are being tested. Many of these satellites have been lost to launch problems.
There is a lot of similarity between the Hacker and the HAM communities in fact some of the first networking code in LINUX is the amateur packet radio code.
Thanks
Bruce
Bruce Perens.
Yes it is a corp, the Radio Amateur Satellite Corporation. See http://www.amsat.org
--fatboy
whew! I was afraid that we'd have to send up four old men into space to stabilize it and hope they don't find the nukes!
"Titanic was 3hr and 17min long. They could have lost 3hr and 17min from that."
IBM had PL/1, with syntax worse than JOSS,
And everywhere the language went, it was a total loss...
Actually, there have been many failures for both amsat and for nasa, and others as well. This is very difficult stuff to get right. While no doubt some improvements can be made in both amsat and nasa, I think they've both done a great job.
While there has been some crossover between the free software movement and amateur radio, there needs to be more. I think that both groups can learn from each other. I'd like to create an atmosphere where ham projects (schematics, etc) are published under a GPL. Software should come to
Linux first (Not trying to get into a religious war here: its just because BSDs and Solaris can run Linux bins). At least, help get ms-dos & ms-win packages to run properly under emulators.
Many people in the free software movement are involved because they value freedom from control by corporations. They like the fact that they can get their hands into the workings and customize and improve the design. Much of the Ham community has the same type of do-it-yourself devotion.
At least one linux distribution has to serve the needs of ham radio operators. I know there is some effort by Debian, but the results are buggy. All of the various ham utilities that are for ms-dos and windows need to be ported to Linux and organized in a reasonable fashion. Once this happens, Linux will start to become more prevalent in the ham community.
As a side question: What was the reasoning behind making the bootloader only turn the carrier on? We decided to make ASUSat1 transmit sensor readings after booting from the ROM. We never got in contact with it long enough to transmit new software, but two other hams received telemetry packets which they forwarded to us. This provided invaluable information when we were trying to figure out what went wrong.
Was the bootloader made as minimal as possible to make software verification easier?
There are a ton of reasons, but the main one is education. First, anyone with a ham license can use these satellites. They are actually very easy to use and it does not require large antenna arrays consisting of 20 foot dishes or millions of dollars of equipment to use them. I have talked through the birds using only a small off the shelf handie talkie and a mobile antenna - total cost for all the equipment was about $500.
These are not just "things slopped together". A whole hell of a lot of engineering goes into them, and there really is not much of a difference between the hamsats and the ones put up by megacorp. They have Earth locators on them. Some sats, like WO-18 had video cameras. Other sats like DO-17 had voice encoders (which did not work for some reason) but would orbit and send down telemetry. Even though you could not use DO-17 for communcation, it was probably the most awesome of the hamsats at the time. I was able to listen to it go overhead without even having an antenna on the receiver, and was able to decode the telemetry packets when I put a rubber duckie antenna on the thing.
Check out the amsat.org web site some more. There are links to things like the University of Surrey satellites and the aformentioned WO-18 made by Weber University.
73 DE NV0U
Those of us in the amateur radio satellite community have gone for a hell of a ride over the last few weeks, and it's good to see things looking up a little. (Nyuk, Nyuk, Nyuk)
73 de Maggie KB3DXS, ARRL 39280, AMSAT 32844
-=Maggie Leber=-
... that Dr. Evil doesn't go trying to snag any of its parts for any evil hacking projects..
;)
(and yes, one can perform evil hacks.. Just ask Bill Gates.. Parlaying a buggy and unoriginal OS into a multi-billion-dollar company qualifies as both a huge hack and amazingly evil.. Just imagine: if Bill Gates can do that much with windows, what Dr. Evil could do with a StrongARM CPU and a FORTH interpreter
"Wow honey, that looks like a giant pair of.."
Your Working Boy,