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Tech support - interplanetary style

Rupert Goodwins AnchorDesk

Published: 18 Apr 2002 18:00 BST

We've all suffered from technical support that takes a day to come up with an answer, if we're lucky. A 24-hour turnaround is nothing to write home about -- unless home is eight billion miles away. That's how far away NASA specialists are from one of their favourite robots, Voyager 1: last week, they successfully reprogrammed the spacecraft in one of the most amazing examples of heroic debugging in the history of technology.

As the probe continued speeding out of the solar system at 40,000 miles an hour, scientists uploaded new software to switch out a gradually fading piece of hardware and switch in backup circuits. As these had never been used in the 25 years Voyager 1 has been in space, and not even tested since 1980, the process was as delicate as they come. It had to be conducted down a deep-space communications link that ran at 160 bits a second and took 12 hours to reach the craft. Responses to commands came a day after they were transmitted. The team expected problems, and they got them.

By any standards, the Voyager programme has been spectacularly successful. The two car-sized spacecraft were launched a month apart in 1977: Voyager 2 first, with Voyager 1 following. They had slightly different trajectories, but both were aimed at Jupiter and Saturn. Voyager 1 got there first, speeding up and out of the solar system after the Saturn encounter. That went well enough to let Voyager 2 take a shot at the outer planets -- the original mission plan was for the first two planets and five years flight.

The extended mission went wonderfully. Voyager 2 returned the only close-up images of Uranus and Neptune, and collected practically all the information we have on the space around those two cold, distant gas giants. New moons, rings, effects and fields have all been discovered -- in some cases, many years after the observations.

One new moon of Uranus -- amazingly, the 18th -- was discovered in 1999, more than 13 years after the spacecraft had moved on: an astronomer was comparing its images with those taken more recently by Hubble. Voyager had snapped one bright spot that wasn't there in the newer pictures: bingo. That data, like all Voyager data, is in the public domain; if you fancy finding some new objects in the solar system and becoming incredibly famous in the elite of planetary astronomers, put away that telescope and hit the Web. The bonus of the extended mission is there for all mankind -- this is the product of a NASA that meant what Neil Armstrong said, not the NASA that refuses to tell us what's going on on the International Space Station.