Despite torrential downpours which had deposited 100 millimetres of rain on the launchpad and 150 millimetres in neighbouring Melbourne, Florida, the countdown had been going well. Until now. NASA took its decision. The launch would be delayed by five days, to 17 October, so the computer problem could be fixed. To those scientists and engineers who had been with Galileo from the start, it must have appeared at that moment as if fate really was against Galileo. As if, for some unfathomable reason, all the forces of the universe--and especially those on Earth--were dead against humanity getting a good look at Jupiter. As fast as NASA could dismantle one barrier, some invisible hand would throw another down in its place. Monday, 16 October, 1989 NASA's Goddard Space Flight Center, Greenbelt, Maryland Across the vast NASA empire, reaching from Maryland to California, from Europe to Japan, NASA workers greeted each other, checked their in-trays for mail, got their cups of coffee, settled into their chairs and tried to login to their computers for a day of solving complex physics problems. But many of the computer systems were behaving very strangely. From the moment staff logged in, it was clear that someone--or something--had taken over. Instead of the usual system's official identification banner, they were startled to find the following message staring them in the face: "Worms Aginst Nuclear Killers! Your System Has Been Officically Wanked. You talk of times of peace for all, and then prepare for war." Wanked? Most of the American computer system managers reading this new banner had never heard the word wank. Who would want to invade NASA's computer systems? And who exactly were the Worms Against Nuclear Killers? Were they some loony fringe group? Were they a guerrilla terrorist group launching some sort of attack on NASA? And why `worms'? A worm was a strange choice of animal mascot for a revolutionary group. Worms were the bottom of the rung. As in `as lowly as a worm'. Who would chose a worm as a symbol of power? As for the nuclear killers, well, that was even stranger. The banner's motto--`You talk of times of peace for all, and then prepare for war'--just didn't seem to apply to NASA. The agency didn't make nuclear missiles, it sent people to the moon. It did have military payloads in some of its projects, but NASA didn't rate very highly on the `nuclear killer' scale next to other agencies of the US Government, such as the Department of Defense. So the question remained: why NASA? And that word, `WANKED'. It did not make sense. What did it mean when a system was `wanked'? It meant NASA had lost control over its computer systems. A NASA scientist logging in to an infected computer on that Monday got the following message: deleted file <filename1> deleted file <filename2> deleted file <filename3>, etc With those lines the computer told the scientist: `I am deleting all your files'.