ONE late September morning in 1988, the space shuttle Discovery roared into orbit while the world watched with bated breath. The flight was the first since the Challenger disaster two-and-a-half years earlier. After a 98-minute delay to replace some misbehaving fuses, the launch went without a hitch. Challenger had been a sobering lesson, but now the shuttle was back in business.
Last month Discovery reprised its 鈥渞eturn-to-flight鈥� role following the 2003 Columbia tragedy. But this time there is no sense of business as usual. Discovery鈥檚 close brush with a large fragment of foam insulation has forced NASA to suspend all shuttle launches until the foam-shedding problem is reworked yet again. And the sight of astronaut Stephen Robinson removing strips of gap filler from Discovery鈥檚 underside by hand highlighted the apparent fragility of the craft.
But the perception of a star-crossed mission is misleading. As NASA officials made clear, the decision to send Robinson after the gap fillers was simply prudence to the nth degree. And the foam problem, while serious, has improved substantially. During lift-off Discovery was hit by only one-sixth as much debris as pre-2003 missions.
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The trouble with human space flight is that perception is everything. Nations that undertake the challenge of sending their citizens into space are engaged in a calculated display of technical prowess. Taxpayers and politicians have been willing to go along with the attendant cost and risk to human life so long as the goal seems worthwhile.
During the post-Challenger hiatus, the concept of 鈥渟pace station Freedom鈥�, built and supplied by the shuttle, was presented as a symbol of the US鈥檚 ingenuity and pioneering spirit. By the Clinton era it had morphed into the International Space Station, the ISS, a high-tech platform for international cooperation, but the vision still allowed the shuttle and space station to move forward together.
Now the programme is at a crossroads. As costs grow and ever more risks connected with flying the shuttle emerge, its perceived value is diminishing. Even before Discovery鈥檚 launch, the shuttle programme was entering its final act. President Bush鈥檚 plan for space exploration requires the completion of the ISS and the shuttles鈥� retirement by 2010. This will free up resources for the Crew Exploration Vehicle (CEV), which will take astronauts to the station in the near term and to the moon by 2020 (see 鈥淪huttle concerns force NASA鈥檚 hand鈥�).
The CEV will get round many of the shuttle鈥檚 problems because it will be designed to do fewer things. It will carry people and leave the job of lifting cargo to a new, unmanned booster. The CEV and booster will both retain some aspects of the shuttle鈥檚 launch system to save on costs, but one feature that will not survive is the side-by-side bundling of fuel tank and payload. That will vanish in favour of a vertical stack that puts crew and hardware safely above falling foam and other debris.
The idea makes so much sense one wonders why NASA is keeping the shuttles flying at all. In fact the space agency is already studying ways to complete the station with fewer shuttle launches. Increasingly, the CEV is emerging as the answer for a public that is not prepared to abandon human space flight but urgently wants NASA to move on.
鈥淣ations that send their citizens into space are engaged in a calculated display of technological prowess鈥�
The risk is that this perception will collide with reality once the CEV is in development. Bold visions rarely come in on time or budget. The last time NASA made such a major switch was when it moved from the massive Saturn V rockets of the Apollo era to the shuttle. That shift took seven years, during which no American flew in space. It was accomplished only with compromises to the shuttle鈥檚 design that meant it would never achieve its goals of making space more accessible and affordable.
The CEV is an attractive idea because it is fresh 鈥� if a little retro. But as it moves forward, setbacks are sure to arise. The goal of travelling to the moon and Mars is far more challenging than building a station in low Earth orbit. The project will need more planning and budget resolve than any previous space programme.
This is why the shuttle is unlikely to disappear just yet. Despite its problems, it is a bridge to the next era, helping NASA keep the experience and momentum it needs for what could be a long transition. If the road ahead is as difficult as recent history suggests, the shuttle era may come to be regarded as the heyday of human space flight.
