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Ion-propulsion engines--in which a portable nuclear reactor heats charged gas and then fires it out the rear of the spacecraft--already exist and are capable of accelerating ships to very high speeds. But the stream of ions the engines produce is a thin one, and even a small ship requires a long time to accelerate--a problem when time is the very thing you're trying to limit. Another possibility is nuclear thermal propulsion, which uses a larger reactor to superheat traditional propellant and blast it out the engine nozzle. Things move a lot faster with such a system, but the engine as a whole is heavier and cruder and the big reactor causes jitters among environmentalists, who would just as soon see nothing nuclear aboard any rocket that could blow up before it leaves the atmosphere. Astronaut Franklin Chang-Diaz says a plasma-propulsion rocket being developed in NASA's labs will go faster still, getting man to Mars in 40 days. Though a decade or more from realization, it uses magnets and abundant gas like hydrogen to produce acceleration.
Perhaps the biggest hole in Bush's speech had to do not with technology but with bureaucracy. It's hard to overstate the stultifying impact the International Space Station has had on NASA since it was first proposed by Ronald Reagan in 1984. The project--advertised initially at $8 billion--is woefully behind schedule and nowhere near completion, and may well cross the $100 billion mark before it's done. No one realistically pretends that any commercial manufacturing will ever take place aboard the thing--a key selling point 20 years ago. Nor can there be much research on the effects of long-term spaceflight on human health--not with the small crews and relatively short stays the station can accommodate. Its current crew does little with its time but maintain hardware and fix problems, the latest being a worrisome oxygen leak that has so far bled away 4% of the station's air since it sprang in late December.
The fact that the Bush proposal didn't kill the orbiting cash hog outright may be because it can't be killed. With contractors and subcontractors across 22 states and uncounted electoral constituencies, the station has long been a kind of cunningly planted political kudzu, impossible to pull out stem and root. If domestic commitments didn't lock the station in place, commitments to NASA's 15 international partners certainly do. And while the station thrives, so too must the three living shuttles, since they exist largely to ferry up parts and crews. "The space station is a failed dream of the '60s and '70s," says Murray. "It's a monument to the past, as is the shuttle."
The six years remaining before the most recent--and possibly still unreliable--target date for the station's completion means six more years of money and labor poured into the seemingly endless project. With shuttle and station operations consuming about 40% of NASA's $15.5 billion annual budget, it's no wonder the President's moon-and-Mars plan calls for no new component to fly until 2014. It's only then that the real spending--perhaps $170 billion, according to NASA's estimates, and probably much more--could begin.