It was vintage Stephen Hawking. Last week the world's most famous astrophysicist, receiving the Royal Society's Copley Medal, Britain's highest scientific award, used the opportunity to warn that "the long-term survival of the human race is at risk so long as it is confined to a single planet." So we must go, as Buzz Light-Year would put it, "to the stars - and beyond!" Hawking first became famous for his triumphant career in science despite being almost totally paralyzed by motor neurone disease: the Royal Society's president, Lord Rees, said he had contributed "as much as anyone since Einstein to our understanding of gravity." His best-selling book A Brief History of Time made him wealthy beyond the dreams of the average Cambridge professor of mathematics. At the age of 64, however, his main concern is the future he will not see. "Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out," Hawking said after the ceremony. "But once we spread out into space and establish independent colonies, our future should be safe. There isn't anywhere like the Earth in the solar system, so we would have to go to another star." By sheer coincidence, just three months ago a decision was made to take the first baby steps in that direction: "We're going for a base on the Moon," said Scott Horowitz, associate administrator for exploration of the US space agency NASA in mid-September. It was part of the roll-out of NASA's plans for the spacecraft that will replace America's aging and accident-prone Space Shuttle fleet, which will be retired in 2010. The Orion vehicles will revert to the simpler methods of the Apollo spacecraft that flew the manned moon missions in 1968-72, launching into orbit atop large rockets and descending back to Earth by parachute, but their technology will be half a century better. THE FIRST job of the Orions when they enter service in 2014 (after an embarrassing four-year gap when US manned space missions must depend on European, Russian or Chinese launch vehicles) will be to meet American commitments in support of the International Space Station. By 2020, however, chief NASA administrator Michael Griffin promises that an Orion will carry a four-person mission to the Moon, the first human visit in almost 50 years. But this time, he said, the visitors will be going to stay - and to "extend human presence across the solar system and beyond." The base will be near one of the Moon's poles, as those are the only parts of the surface where there is continuous sunlight to provide power (and there may even be frozen water available in some of the craters). It will serve not only as a science center but a possible stepping stone to Mars. That's about 100 times as far away - the first step out of the wading pool and into the ocean - but manned missions to Mars are now officially on the agenda as well. "I can't believe that we're not already living and working on Mars," said Elliot Pulham, president of the Space Foundation, an industry trade organization, in response to NASA's September announcement. "It's a shame we wasted the past 20 or 30 years, but we do need to get back on track and get on with this sooner or later." It is a bit late, but full credit to President George W. Bush, who responded to the latest Shuttle disaster in 2003 by becoming the first American leader to get serious about space flight in decades. The question is whether the commitment will survive Bush's departure in two years' time: a Congress bitter about the lost war in Vietnam gutted the funding for the first US Moon project, and a Congress bitter about the lost war in Iraq could do the same again. This time, however, the US is no longer the only major player. The European Union and Russia are currently doing a feasibility study for a joint rocket and manned vehicle program based on their existing Ariane and Soyuz technologies, China is already in the manned space-flight business, and both Japan and India have clear ambitions in that direction. With or without American involvement, bases on the Moon are likely in less than 20 years, and on Mars in perhaps another decade. That doesn't really add up to "independent colonies" that satisfy Hawking's criteria, however, because human beings cannot live anywhere in the solar system apart from Earth without hugely expensive and vulnerable life support systems. To find other habitable planets we must go to the stars, a journey many tens of thousands of times farther than the trip to Mars - barring some completely unforeseen scientific and technological revolution, that will not happen in this century. But unless global civilization suffers an early and comprehensive collapse, the logic of human history suggests that it probably will happen eventually, one way or another. Will that finally make us safe from extinction? A little bit safer, maybe, but any technology that can take us to the stars can probably also destroy whole planets at interstellar range. No matter how far we go, we can never get away from ourselves. The writer is a London-based independent journalist whose articles are published in some 45 countries.