Wednesday, February 07, 2007


As a child of the 60s, I grew up with the "Space Race". I spent countless hours watching and reading about every Mercury, Gemini and Apollo manned space mission. So when I read this on QRP-L today, I was immediately tantalized! Count on Paul Harden NA5N to post about another fascinating subject on QRP-L. This appeared today about the Voyager space probes:

"The last update on the JPL website on the Voyager I and II status is:
This was the status in late 2006. Just add a few million miles or so to the numbers for Feb. 2007 :-) It was nuke-powered, with the small nuclear reactor mounted on the end of a long boom to get it away from the instrument package. Both are still being received. Signals are so weak, it requires a very slow data rate to send any useful information, such that it's not doing much science except sending a beacon and a particle detector count at most times.

Signals are monitored by JPL Goldstone and other facilities, and by the DSN (Deep Space Network) for special experiments. Last I heard, it takes about 30 hours to get a message to voyager. Thus, to send a signal to turn on a science instrument, wait for the answer, collect some data, then turn things off as quick as possible to save power takes DAYS. This is seldom done.

The next hopeful job of Voyager will be the day the signal strength suddenly changes, followed by a sudden increase in particle count, then a dramatic drop in the particle count. This would be when Voyager passes through the boundary of the heliopause. The heliosphere is the giant envelope that surrounds our solar system, and the heliopause boundary is the "wall" where all the particles from our sun suddenly stop moving as they reach equilibrium from the pressure coming towards us from the rest of the universe. Scientists have absolutely no idea how far the influence of our sun extends. If either Voyager manages to pass through the heliopause, it would be a major scientific discovery.

It is my understanding that Voyager receives almost no funding. Apparently, a couple of JPL workers check the beacon signal strength plots about once a week to ensure we're still receiving it. This would imply some antenna somewhere monitors it constantly, which I don't even think is the case.

We have a couple of people visiting next week from JPL. If I see them, I will ask them for details, as I'm curious myself. Regardless, Voyager I and II clearly have the record for "miles per watt," and clearly QRPpppp. And perhaps the record for the longest operating nuclear reactor without a fast scram recovery (sorry - a little OT nuke humor).

72, Paul NA5N"

Once again, many thanks, Paul! A combination of my two my favorite subjects - amateur radio and the space program. This was definitely much better reading than the sordid details of an astronaut love triangle.

73 de Larry W2LJ

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