Nasa is set to dispatch seven astronauts on its most dangerous ever shuttle mission as it attempts to rescue the $7 billion Hubble Space Telescope from meltdown.
Led by former US Navy fighter pilot Scott Altman, 49, a one-time stunt flier for actor Tom Cruise in the film Top Gun, the crew of Atlantis will repair and upgrade the orbiting observatory, risking a potentially deadly space-junk collision that could leave them stranded 350 miles above Earth.
The mission, which is costing Nasa $1.4 billion and is due to blast off from Florida tomorrow, is considered so perilous that it was once canceled by space agency chiefs who feared that it could cost the astronauts their lives.
It was resurrected only after they agreed to place a second shuttle and crew on emergency standby, ready to blast into space to save their colleagues should a catastrophe occur. The move is unprecedented in the 28-year history of the shuttle fleet.
Should a rescue become necessary, it would provide the greatest space drama since the abortive Apollo 13 lunar mission in 1970, say Nasa insiders, when three astronauts limped their crippled spacecraft home just hours from death, following an on-board explosion.
Among the greatest hazards facing Atlantis is the intense amount of space junk - such as broken satellites and dead rockets - that is cluttering the area where the shuttle will rendezvous with Hubble.
Shuttle flights usually only go to the International Space Station no more than 250 miles up - but at 350 miles, where Hubble flies, the hazards are far greater.
If Atlantis suffers damage, the crew would be marooned.
Led by former US Navy fighter pilot Scott Altman, 49, a one-time stunt flier for actor Tom Cruise in the film Top Gun, the crew of Atlantis will repair and upgrade the orbiting observatory, risking a potentially deadly space-junk collision that could leave them stranded 350 miles above Earth.
The mission, which is costing Nasa $1.4 billion and is due to blast off from Florida tomorrow, is considered so perilous that it was once canceled by space agency chiefs who feared that it could cost the astronauts their lives.
It was resurrected only after they agreed to place a second shuttle and crew on emergency standby, ready to blast into space to save their colleagues should a catastrophe occur. The move is unprecedented in the 28-year history of the shuttle fleet.
Should a rescue become necessary, it would provide the greatest space drama since the abortive Apollo 13 lunar mission in 1970, say Nasa insiders, when three astronauts limped their crippled spacecraft home just hours from death, following an on-board explosion.
Among the greatest hazards facing Atlantis is the intense amount of space junk - such as broken satellites and dead rockets - that is cluttering the area where the shuttle will rendezvous with Hubble.
Shuttle flights usually only go to the International Space Station no more than 250 miles up - but at 350 miles, where Hubble flies, the hazards are far greater.
If Atlantis suffers damage, the crew would be marooned.