NASA managers asked shuttle engineers to assess retargeting the final two space shuttle missions, moving the launch of Discovery from mid-September to October 29 and the flight of Endeavour from late November to February 28. The changes would give engineers more time to optimize payloads bound for the International Space Station and avoid launch conflicts with other flights to the lab complex.
The status of a proposed final fight of the shuttle Atlantis next June to deliver a final load of supplies and equipment remains unresolved. Bill Gerstenmaier, director of space operations at NASA headquarters, said earlier this year he hoped to have a decision by the end of this month, but officials said Tuesday the discussion had been deferred to the August timeframe.
A decision on delaying the next two missions, however, is expected July 1, after a two-week review.
Assuming an October 29 target date, Discovery would blast off at 23:44 GMT and dock with the station the afternoon of October 31. Two spacewalks would be carried out Nov. 2 and 4. Discovery would undock the morning of November 7 and land back at the Kennedy Space Center the afternoon of November 9.
Shuttle mission STS-133 will be commanded by former chief astronaut Steven Lindsey. His crew mates are pilot Eric Boe, station veterans Nicole Stott and Michael Barratt and spacewalkers Alvin Drew and Timothy Kopra, another station veteran.
Endeavour, commanded by Mark Kelly, would blast off around 22:31 GMT on February 28 to deliver critical supplies and a $1.5 billion physics experiment to the space station. Joining Kelly for mission STS-134 will be pilot Gregory Johnson, Hubble veteran Andrew Feustel, European Space Agency astronaut Roberto Vittori and station veterans Gregory Chamitoff and Mike Fincke.
NASA originally planned to end shuttle operations by the end of fiscal 2010, launching Endeavour in July and Discovery in mid September. But problems with the Alpha Magnetic Spectrometer scheduled for launch aboard Endeavour forced program managers to delay the July flight to the end of November.
Atlantis is being processed to serve as an emergency rescue vehicle for Endeavour's crew. But if a rescue flight is not needed, NASA managers believe the standby shuttle could be launched with a crew of four, relying on Russian Soyuz capsules to ferry the crew members home if a major problem blocked a safe re-entry.