Jim Bassett's Weblog

Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA Headquarters, Washington, said, "NASA launched the Mars Exploration Rover mission specifically to check whether at least one part of Mars ever had a persistently wet environment that could possibly have been hospitable to life. Today we have strong evidence for an exciting answer: Yes."

So now we just have to get some of the sedimentary rocks back to earth (not part of these missions) and look for the fossils. I wonder if finding proof of "life as we know it" on another planet will be a big story or not.

"AMSAT-OSCAR 7 was launched November 15, 1974 by a Delta 2310 launcher from Vandenberg Air Force Base, Lompoc, California. AO-7 was launched piggyback with ITOS-G (NOAA 4) and the Spanish INTASAT.... AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981.� Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:"

From: "pat gowen"
To:
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!....

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

To which Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager responded:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!!

Wow. Solar power is so cool. The idea that a 30 year old communications satellite is still up there, and operational when in sunlight, is pretty impressive. And scary.

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