MORE Republicans are against it than for it and more than half of the American public at large thinks it a waste of money. So far, George Bush鈥檚 plan to send people back to the moon, and thence Mars, has won only a glum thumbs-down in the opinion polls. If the cynics are right and last week鈥檚 speech really was no more than an electioneering ploy, then its vote-winning powers are already looking thin.
To be fair, a lot of Big Science projects would struggle to win support in such polls. To the wider public, building hospitals and schools will always seem a more pressing 鈥� and moral 鈥� way to use taxpayers鈥� money than searching for, say, dark matter or the Higgs boson. But in the case of Bush鈥檚 moon shot, the worries run deeper than a simple aversion to science.
Leaving aside concerns over NASA鈥檚 ability to deliver (see 鈥淕eorge Bush and his improbable dream鈥�), where are the detailed cost estimates? Lunar bases and manned missions to Mars are likely to swallow hundreds of billions of dollars. Bush believes the initial costs can be met by retiring the shuttle and throwing NASA an extra billion over five years. This is very optimistic, and the agency鈥檚 track record suggests that all its estimates should be treated cautiously. Each shuttle launch, for example, was supposed to cost a tenth as much as that of an expendable rocket, but its real cost was 10 times as much.
Advertisement
Already there is an expectation that the new plans will put other NASA space science projects at risk. Ballooning budgets will jeopardise them still more, and that is likely to mean fewer unmanned probes reporting back on the mysteries of the solar system. Is this a price worth paying? Perhaps, but before that can be judged, the proponents of manned space exploration must do a better job of explaining why we are sending people to the moon and Mars.
On the one hand, the discovery of life 鈥� or its remnants 鈥� on Mars would be worth a high price. Strangely, Bush did not mention this as a priority for the manned missions. On the other, some arguments in favour of his plan ring hollow. Enthusiasts say NASA needs a new long-term goal to compensate for the loss of Columbia, the aimlessness of the international space station and the launch of the first Chinese astronaut, which have left NASA bereaved and humiliated. But the public cannot be expected to back a vague, uncosted mission to Mars solely to give a government agency a purpose in life.
A claim with more traction is that astronauts are smarter and more flexible than machines, and so have a better chance of fixing faults and doing the right science. That said, there are few examples of space science that absolutely need humans to be present. The exception is research into the effects of hostile conditions in space on our bodies 鈥� but that is useful only if we want to send people into space. It is also easy to miss the advantages machines have over frail flesh. As the American physicist Robert Park remarked of NASA鈥檚 Sojourner Mars probe: 鈥淚t rambled around never complaining of the cold nights or breaking for lunch.鈥� Nor did it get radiation sickness en route or have to be brought home.
In the end, of course, the debate over whether we really need astronauts to venture into space cannot be settled without factoring in an entirely different dimension. Exploring space and gathering data are not the same thing at all. As Bush puts it: 鈥淭he human thirst for knowledge ultimately cannot be satisfied by even the most vivid pictures or the most detailed measurements. We need to see and examine and touch for ourselves.鈥�
There can be no doubt that the first human steps on Mars would excite as much interest as Neil Armstrong鈥檚 on the moon. So is Bush right? The answer depends on whether you think the desire to touch new worlds is an inspiring human challenge. Or whether you think the sense of purpose and progress that sending people into space offers is illusory. This is the underlying philosophical fault line in the debate, and it has as much to do with visions of human destiny as it does with science.