NASA clears Discovery heat shield for landing

Adam Turner
Friday, 22 December 2006 03:57

Science - Space

NASA engineers have cleared Space Shuttle Discovery for re-entry, with three landing sites to be prepared as the shuttle runs on emergency fuel.

 

Discovery is scheduled to land on Friday afternoon, but weather forecast are for possible low clouds and rain at Kennedy Space Center for Friday and Saturday. The shuttle must land by Saturday or fuel cells providing power to the craft will run dry. Normally shuttle missions have two bad weather days in reserve, but NASA used one of Discovery's spare days to extend its stay at the International Space Station to repair a stubborn solar panel.

With only 24 hours of reserve fuel and unfavourable weather at Kennedy Space Center in Florida, NASA is preparing backup landing sites at Edwards Air Force Base in California and White Sands, New Mexico. High cross winds are forecast at Edwards on Friday, but White Sands is currently clear. Landing at Edwards will delay the next shuttle launch by a one week, but landing at White Sands will push back Discovery's relaunch date at least a month.  Only one shuttle has ever landed at White Sands, in 1982.

Discovery's heat shield has been cleared for re-entry tomorrow after astronauts spent Wednesday day examining the re-enforced leading edge panels on Discovery's wings and nose cap, taking video and laser observations for analysis back on Earth. Discovery's crew used the shuttle’s robotic arm and boom extension sensor system to check the heat shield for any space junk or micrometeoroid hits that may have occurred while docked with the International Space Station.

Such inspections are routine since damage to a fuel tank lead to the death of Columbia's seven astronauts during re-entry in 2003. Despite this, NASA had been considering skipping the inspection rather than use up one of Discovery's two spare days bad weather days.

Discovery’s first landing opportunity is scheduled at 3.56 pm EST Friday (7.32am AEST Saturday ) at Kennedy Space Center and the last at Kennedy on 5.32pm (9.32am AEST). Three landing windows exist at Edwards on Friday – 5.27pm, 7pm and 8.36pm Two are available at White Sands – 5.27pm and 7.02pm. Landing opportunities also are available Saturday at all three sites.