space, a giant void free of human life which could play host to a bit of radioactive plutonium 238 dioxide. The plutonium was compact for the amount of energy it gave off—and it lasted a long time. It seemed logical enough. Pop just under 24 kilograms of plutonium in a lead box, let it heat up through its own decay, generate electricity for the probe's instruments, and presto! Galileo would be on its way to investigate Jupiter.

American anti-nuclear activists didn't quite see it that way. They figured what goes up might come down. And they didn't much like the idea of plutonium rain. NASA assured them Galileo's power pack was quite safe. The agency spent about $50 million on tests which supposedly proved the probe's generators were very safe. They would survive intact in the face of any number of terrible explosions, mishaps and accidents. NASA told journalists that the odds of a plutonium release due to `inadvertent atmospheric re-entry' were 1 in 2 million. The likelihood of a plutonium radiation leak as a result of a launch disaster was a reassuring 1 in 2700.

The activists weren't having a bar of it. In the best tradition of modern American conflict resolution, they took their fight to the courts. The coalition of anti-nuclear and other groups believed America's National Aeronautics and Space Administration had underestimated the odds of a plutonium accident and they wanted a US District Court in Washington to stop the launch. The injunction application went in, and the stakes went up. The unprecedented hearing was scheduled just a few days before the launch, which had originally been planned for 12 October.

For weeks, the protesters had been out in force, demonstrating and seizing media attention. Things had become very heated. On Saturday, 7 October, sign-wielding activists fitted themselves out with gas masks and walked around on street corners in nearby Cape Canaveral in protest. At 8 a.m. on Monday, 9 October, NASA started the countdown for the Thursday blast-off. But as Atlantis's clock began ticking toward take-off, activists from the Florida Coalition for Peace and Justice demonstrated at the centre's tourist complex.

That these protests had already taken some of the shine off NASA's bold space mission was the least of the agency's worries. The real headache was that the Florida Coalition told the media it would `put people on the launchpad in a non-violent protest'.3 The coalition's director, Bruce Gagnon, put the threat in folksy terms, portraying the protesters as the little people rebelling against a big bad government agency. President Jeremy Rivkin of the Foundation on Economic Trends, another protest group, also drove a wedge between `the people' and `NASA's people'. He told UPI, `The astronauts volunteered for this mission. Those around the world who may be the victims of radiation contamination have not volunteered.'4

But the protesters weren't the only people working the media. NASA knew how to handle the press. They simply rolled out their superstars—the astronauts themselves. These men and women were, after all, frontier heroes who dared to venture into cold, dark space on behalf of all humanity. Atlantis commander Donald Williams didn't hit out at the protesters in a blunt fashion, he just damned them from an aloof distance. `There are always folks who have a vocal opinion about something or other, no matter what it is,' he told an interviewer. `On the other hand, it's easy to carry a sign. It's not so easy to go forth and do something worthwhile.'5

NASA had another trump card in the families of the heroes. Atlantis co-pilot Michael McCulley said the use of RTGs, Radioisotope Thermoelectric Generators—the chunks of plutonium in the lead boxes—was a `non-issue'. So much so, in fact, that he planned to have his loved ones at the Space Center when Atlantis took off.

Maybe the astronauts were nutty risk-takers, as the protesters implied, but a hero would never put his family in danger. Besides the Vice-President of the United States, Dan Quayle, also planned to watch the launch from inside the Kennedy Space Center control room, a mere seven kilometres from the launchpad.

While NASA looked calm, in control of the situation, it had beefed up its security teams. It had about 200 security guards watching the launch site. NASA just wasn't taking any chances. The agency's scientists had waited too long for this moment. Galileo's parade would not be rained on by a bunch of peaceniks.

The launch was already running late as it was—almost seven years late. Congress gave the Galileo project its stamp of approval way back in 1977 and the probe, which had been budgeted to cost about $400 million, was scheduled to be launched in 1982. However, things began going wrong almost from the start.

In 1979, NASA pushed the flight out to 1984 because of shuttle development problems. Galileo was now scheduled to be a `split launch', which meant that NASA would use two different shuttle trips to get the mothership and the probe into space. By 1981, with costs spiralling upwards, NASA made major changes to the project. It stopped work on Galileo's planned three-stage booster system in favour of a different system and pushed out the launch deadline yet again, this time to 1985. After a federal Budget cut fight in 1981 to save Galileo's booster development program, NASA moved the launch yet again, to May 1986. The 1986 Challenger disaster, however, saw NASA change Galileo's booster system for safety reasons, resulting in yet more delays.

The best option seemed to be a two-stage, solid-fuel IUS system. There was only one problem. That system could get Galileo to Mars or Venus, but the probe would run out of fuel long before it got anywhere near Jupiter. Then Roger Diehl of NASA's Jet Propulsion Laboratory had a good idea. Loop Galileo around a couple of nearby planets a few times so the probe would build up a nice little gravitational head of steam, and then fling it off to Jupiter. Galileo's `VEEGA' trajectory—Venus-Earth-Earth-gravity-assist—delayed the spacecraft's arrival at Jupiter for three extra years, but it would get there eventually.

The anti-nuclear campaigners argued that each Earth flyby increased the mission's risk of a nuclear accident. But in NASA's view, such was the price of a successful slingshot.

Galileo experienced other delays getting off the ground. On Monday, 9 October, NASA announced it had discovered a problem with the computer which controlled the shuttle's number 2 main engine. True, the problem was with Atlantis, not Galileo. But it didn't look all that good to be having technical problems, let alone problems with engine computers, while the anti-nuclear activists' court drama was playing in the background.

NASA's engineers debated the computer problem in a cross-country teleconference. Rectifying it would delay blast-off by more than a few hours. It would likely take days. And Galileo didn't have many of those. Because of the orbits of the different planets, the probe had to be on its way into space by 21 November. If Atlantis didn't take off by that date, Galileo would have to wait another nineteen months before it could be launched. The project was already $1 billion over its original $400 million budget. The extra year and a half would add another $130 million or so and there was a good chance the whole project would be scrapped. It was pretty much now or never for Galileo.

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