Astronauts on shuttle Atlantis conducted a final inspection of their spacecraft’s heat shield on Monday as they began early preparations for their return to Earth.
They used a sensor-laden robot arm to scan the shuttle’s wings and other surfaces that bear the brunt of the super-hot temperatures the spacecraft experiences as it glides through the atmosphere to a landing at the Kennedy Space Centre in Florida.
In an earlier inspection on September 11, they looked for any damage that might have occurred during launch, but found none.
This time they were looking for potential damage from debris and micro-meteroids that hurtle through space undetected and might have struck the shuttle during flight.
While Nasa says the chances of such damage are low, the heat shield inspections are now part of shuttle life due to safety procedures put in place after the 2003 Columbia disaster.
The damage inspections take several hours as the robot arm slowly pores over the shuttle surface, collecting data and images that will be examined by Nasa experts on Earth.
Columbia broke apart while returning to Earth on February 1 2003 due to heat-shield damage suffered at launch that went undetected. The seven astronauts on board were killed.
Nasa has spent more than $1-billion on safety upgrades and implemented procedures such as the heat shield inspections to avoid another shuttle disaster.
The Atlantis mission follows two test flights to test the safety changes and is the first to resume construction of the International Space Station after a nearly four-year hiatus.
Solar power
It delivered and installed a $372-million, 17-and-a-half tonne solar power unit and truss structure that will double electricity output as Nasa works to complete the half-finished station.
The space agency plans 14 more shuttle flights to finish the $100-billion space complex before the shuttle programme is ended in 2010.
Atlantis arrived at the space station on September 11 and undocked on Sunday after completing its work, which included three spacewalks by shuttle astronauts.
While conducting its inspection, the shuttle remained about 80km away from the station in case the heat shield scan turned up sufficiently dangerous damage to force Atlantis to return to the station and take refuge there while awaiting a rescue flight.
When the shuttle returns to Earth on Wednesday a Russian Soyuz spacecraft is due to arrive, carrying three crewmembers, including space tourist Anousheh Ansari.
The Soyuz launched on Monday from Baikonur Cosmodrome in Kazakhstan.
Along with Ansari are Russian cosmonaut Mikhail Tyurin and US astronaut Michael Lopez-Alegria, replacements for station crewmembers Jeff Williams and Pavel Vinogradov who are set to come home after six months on the outpost.
Ansari, an Iranian-born American businesswoman who is believed to have paid $20-million to go on the spaceflight, will return to Earth with Williams and Vinogradov on the Soyuz on September 28.
Also on Monday, an unmanned supply spacecraft was to undock from the space station and drop into the earth’s atmosphere, where it was supposed to burn up harmlessly over the Pacific Ocean.
”It’s a busy week in space,” Williams told mission control in Houston. – Reuters