With the loss of the space shuttle Columbia, Nasa chiefs now face a slow humiliation — the gradual collapse of the £60-billion international space station. This now circles 288 kilometres above earth but is losing altitude with every orbit.
The space shuttle fleet not only ferried supplies, air, scientific equipment and new crews to the space station, it also routinely supplied some extra height. With almost every visit, the shuttle’s powerful engines would raise the structure’s orbit by 30 miles or so, and save its crew from that sinking feeling.
Once complete, the ISS will be a huge structure roughly the size of a sports stadium, orbiting above the atmosphere, and one of the brightest things in the night sky. But at any time there are tenuous wisps of gas at that altitude. During moments of violent sunspot activity, the planet’s upper atmosphere can heat and expand, reaching out to orbiting spacecraft. The effect would be barely noticeable but enough to act as drag. Any drag at all would slow the space station; once slowed, it would begin a gradual fall back to earth.
If left untended, Nasa’s proudest investment would ultimately end in a fireball in the sky and a cascade of blazing metal over the planet.
There are three men on the station now: the station commander, Ken Bowersox, flight engineer Donald Pettit, both American, and a Russian flight engineer, Nikolai Budarin. They had hoped to return by shuttle in March. But with the remaining three shuttles grounded, they may have to stay until June, and rely on a tiny Russian space ”lifeboat” for any emergency.
Nasa officials on Sunday said a Russian Progress spacecraft could supply and boost the space station — one took off on a routine supply visit that day — but yesterday the Russians seemed less confident.
The shuttle can carry seven people and a 25-ton payload; Russia’s Progress and Soyuz capsules can carry only three people and 2,5 ton.
The once-triumphant Russian space industry is now struggling to survive — it is likely only to be able to provide the three unmanned Progress supply ships and two manned Soyuz expeditions that have already been promised. If there are no more shuttle flights, then the Russians would have to send three more Progress ships. There is no more money for these ships, according to one unnamed source in Moscow — and even if there were, they could not be ready before 2004.
”In my opinion, the ISS will have to be frozen, maybe for a year, maybe more,” Igor Marinin, editor of the specialised publication Novosti Kosmonavtiki, told Reuters. ”The next ISS crew will go up essentially to close it down for a time.”
Yuri Grigoriev, of the RKK Energia corporation which builds Soyuz, said: ”Technically, this means there is the possibility of leaving the station unmanned and freezing development, and this is a huge risk. The station was designed for permanent staffing and requires constant attention.”
Expensive luxury
This leaves the US space agency facing a dilemma. Without the space shuttle, it can neither finish construction on the station, nor even maintain it. On the other hand, the existence of the space station was its excuse for maintaining the shuttle fleet in the first place. It has faced budget cuts of 40% in the past decade.
The dilemma provides ammunition for a vocal scientific lobby that has argued for a decade that the space station was an expensive luxury, and the agency’s manned flight programme a waste of money that could be better spent on unmanned missions.
”Nasa’s done a good job when it comes to deep space missions,” one critic told a conference last year. ”The space station is digging a ditch and the shuttle is filling it. These are two programmes which are unjustifiable in and of themselves and only justifiable if the other exists.”
The most fruitful space missions involve robot control. Voyager spacecraft are heading out beyond the orbit of Pluto, a joint US-European mission is on the way to Saturn, and a Nasa spaceprobe is preparing to sail through a comet’s coma and collect some of the primordial fabric of the solar system.
Daniel Goldin, until recently Nasa’s administrator, always robustly defended the manned space programme. ”If robots were that useful,” he said ”we’d be using them down here too.”
But Sir Martin Rees, Britain’s astronomer royal, argued that unmanned missions delivered more. ”My line has always been that as a scientist I have always been against men in space, even though as a human being I have been in favour, because in the long run there is going to be a role for people in space. But not, probably, the way it is being done now,” he said yesterday.
”There is a more serious long-term issue. I don’t think it is ever feasible to get to the safety level which the American public expects of a publicly supported programme involving civilians. One has to accept that there will be these accidents, and there is an inherent problem. The American public is not prepared to accept them. In other words, they are not prepared to treat astronauts like test pilots, or like independent, self-financed adventurers.” – Guardian Unlimited Â