Tim Furniss/LONDON

NASA is considering asking Russia to delay the launch of the first component of the International Space Station (ISS) from June to August, to even out the 1998 Space Shuttle launch schedule. The US space agency has also admitted that the launch of the US developed Laboratory Module could be delayed by production difficulties at Boeing.

Russia says that a projected "three month delay" to the launch of the Laboratory Module beyond the original May 1999 schedule is the real reason for the expected delay in putting the first ISS components into space.

Although the Russian Control Module is being prepared for flight aboard a Proton launcher next June, the NASA view is that there is no point in having several ISS components in orbit for longer than necessary before the arrival of the Laboratory Module.

NASA Administrator Daniel Goldin says that the Shuttle schedule has been disrupted by technical difficulties in preparing the Advanced X Ray Astrophysics Facility (AXAF) for launch in August.

The AXAF (unrelated to the ISS programme) is now tentatively scheduled for a December launch at the earliest - conflicting with two scheduled ISS launches. There is a need to spread seven Shuttle flights throughout this year so that there are no long gaps in launches followed by frenetic activity.

In addition, the Discovery and Endeavour orbiters are equipped for ISS missions and only the Columbia will be able to launch the AXAF as planned.

Goldin says that it is likely that the second mission of 1998 - the STS90/Neurolab - will be pushed back two weeks to 16 April, followed by the STS91/Discovery Shuttle Mir Mission in June.

The STS88/Endeavour flight, carrying the first US ISS components to dock with the Control Module, may now be launched in September, followed by the STS95/Discovery research mission in late October.

The AXAF could then follow, slipping an ISS logistics Shuttle flight, the STS96/Endeavour, into 1999, before a third ISS mission, the STS92/Atlantis - originally the first of eight planned missions in 1999 (seven dedicated to the ISS) -can fly.

Source: Flight International