'We will just have to get through it and see how it turns out,' said Nasa chief Mike Griffin at a briefing about tomorrow's landing. 'This manned spaceflight stuff is really hard.'
The agency is particularly jittery because it had to ground its entire shuttle fleet last week after a large chunk of insulating foam was spotted falling from an external fuel tank during Discovery's launch, a problem that doomed Columbia in 2002.
Managers reckoned they had fixed the foam insu-lation problems during the 30-month grounding of the fleet that followed that tragedy. More than £1 billion was spent on refits. Now Nasa is back to square one.
'We are seeing the death throes of the space shuttle,' said Dr John Logsdon, director of the space policy institute at George Washington University. 'The problem is not that the machinery is old but the whole concept was a mistake. The shuttle is an evolutionary dead-end.'
For a start, the shuttle is overly complex; it has 300,000 moving parts. By contrast, SpaceShipOne, the world's first private spaceplane - flown for the first time last year - has 30. As one space engineer put it: 'Complexity means fuck-ups. Simplicity means safety.'
The decision to place the manned orbiter beside, rather than on top of, the shuttle's fuel tanks has also had dire consequences: Columbia was wrecked by falling insulation from the top of a fuel tank, which damaged its heat protection tiles so it disintegrated during re-entry.
In addition, using a single craft to carry both humans and cargo is now seen as a major blunder. Hence Nasa's decision - revealed last week - to replace the shuttle with two very different spacecraft: a manned capsule to be launched on top of a medium-sized rocket and a huge cargo launcher to put Moon and Mars vehicles in orbit.
'Separating crew and cargo functions and putting manned capsules on top of rockets will improve safety enormously,' added Logsdon. 'Astronauts have less than a one in 100 chance of dying on the shuttle at present. That is simply not good enough.'
No comments:
Post a Comment