NASA administrator Michael Griffin has told the International Space Station (ISS) partners that they will have to be flexible on the assembly schedule because of uncertainty over the Space Shuttle’s future.

The international partners are expecting the Shuttle to launch their components of the ISS, which includes Europe’s Columbus and Japan’s Kibo experiment modules.

Griffin says that the Shuttle’s performance during the return to flight missions expected in July and September will determine its future. Originally there were 28 flights scheduled for ISS completion in 2010. Griffin indicates that it is unlikely this will be achieved before the Shuttle fleet is retired in 2010.

“I will tell the partners we need flexibility [because we] can’t guarantee that the Shuttle can [complete assembly]. Some of that might be left to the new system,” says Griffin.

The new system is a heavylift vehicle for which Griffin wants to use existing Space Shuttle technology. The system would use the Shuttle’s solid rocket boosters and external tank, upon which a cargo pod would be side-mounted. The heavylift would operate after 2010, pushing ISS completion into the next decade.

Source: Flight International