BellaOnline Forums Education Astronomy Last signal from Pioneer 10 - January 22, 2003

Pioneer 10, launched March 2, 1972, was a true pioneer. The first spacecraft to cross the asteroid belt, first to complete a mission to Jupiter and first to send information about the distant regions of the Solar System. Its last message came home on January 22, 2003 on its way out of the Solar System towards Taurus.

Ten years later it's ten billion miles away from the Sun. A ray of sunlight takes nearly fifteen hours to reach it!

Pioneer 10 and Pioneer 11 both carried information plaques devised by Carl Sagan and Frank Drake.



It assumes that an intelligent space-faring race could use their own scientific knowledge to work out where the message came from. Some people felt this was irresponsible, but it just seemed like a grand gesture to me. Even now Pioneer 10 is around 100,000 years away from our very nearest star, not to mention being a tiny object in a very large space.

Both Pioneer 10 and its sister probe Pioneer 11 have gone more slowly than they should - it's a teensy, but measurable, amount of slowing that couldn't be accounted for. It's spawned all sorts of explanatory theories, many of them quite daft.

Finally, someone searched out the old data, which is in formats no longer in use. So that meant finding old equipment to play them and then transferring the data to a current format in order to analyze it.

When they did, they finally concluded that the miniscule slowing resulted from the heat radiation of the probes pushing against them and slowing them down. So probably no new exotic physics and no aliens involved.

More detail at Mystery Tug on Pioneer 10 and 11.