Discovery is safe, but what next for the fleet?

Space Shuttle Atlantis sits in the vehicle assembly building at Kennedy Space Center, its processing for International Space Station (ISS) supply mission STS 121 on hold. Its supposed to take place in September but at the post-Discovery landing press conference NASA chief Mike Griffin would not guarantee another flight this year. Following the loss of large pieces of foam from Discovery's external tank shuttle programme engineers are not even confident that 2006 will see another shuttle launch.

Interestingly at the Discovery landing press conference Griffin talked about retirement of the fleet, which is scheduled for 2010, and how that would be the only driver for when the shuttle flew. Before NASA administrators always spoke of the construction of the ISS as being the driver for the launch schedule. But after the Columbia disaster and the loss of foam from Discovery's ascent, the tone and tempo of their comments has changed.

Retirement for the fleet may not mean all three remaining shuttles, Discovery, Atlantis and Endeavour being retired at the same time. There are rumours that Discovery, now the oldest shuttle at 22 years of age, could be retired in 2007. That would severely limit NASA's ability to construct the ISS. But then Griffin has already admitted that NASA might complete the station without shuttle. 

Why retire shuttles early? To have the money to develop new launch systems, based on the shuttle technology. With further work required for resolving the foam loss problems the agency couldn't resolve for the past two and half years,  NASA's request for around $200 million for "return to flight activities" for 2006 is likely to be inadequate. This year NASA will spend over $600 million. The extra millions next year will eat into NASA's plans for that new launch system, which are expected to be made public in the next two weeks. So retiring one orbiter sounds like a good idea. But will Griffin face opposition for this, if he were to do it? 

What can Griffin do to avoid the budget crunch everyone is expecting, when you are trying to fly an aging shuttle fleet safer than at any other time, trying to develop new launch systems and spacecraft by 2010, and prepare for the return to the Moon expected by President George Bush's Vision for Space Exploration? Does Griffin have a master plan or is he simply hoping that force of will mean more funds from the US Congress?