Tim Furniss/LONDON

All eyes are on the much-delayed STS88 Endeavour mission on 3 December, the purpose of which is to carry the Unity Node 1 and link it with the Russian Zarya control module, to establish the first part of the International Space Station (ISS).

Endeavour's mission depends on the successful launch of Zarya aboard a three-stage Proton from Baikonur on 20 November. Lift off is scheduled from Pad 81L at 06.40 GMT. The 20,700kg (59,500kg) Zarya should be in orbit about 9 min 47s later. If it is lost, assembly of the ISS would be delayed until a second control module, under construction at Russia's Khrunichev, is ready next year.

The loss of the Zarya would decimate the ISS programme and reduce NASA's Shuttle fleet to virtual redundancy in 1999. Occupation of the ISS by the first international crew would be postponed beyond the already much delayed January 2000 target date.

The Zarya flight is surrounded by fresh controversy. NASA Watch, the space agency watchdog in Washington DC, has learned that in the view of NASA's manned spaceflight chief, George Abbey, the control module has failed its flight readiness review because of excessive noise, which will require all crews to wear industrial-class ear plugs to work inside it. The launch has been cleared, however.

In addition, Russia requested permission to launch Zarya into a co-planar orbit that is compatible with the Mir space station. In the event of the ISS project collapsing, the Zarya could be linked to Mir, the lifetime of which is likely to be extended beyond its planned June 1999 de-orbiting. The Russian Space Agency has formally requested an extension to operations of the Mir from the Russian Government.

If Russia's Service Module is delivered late and its planned July 1999 launch delayed significantly, it may be necessary to dock the Zarya (with the Unity Node 1) with the Mir anyway, because these units cannot operate independently for a long period.

A third reason for Russia's request - seen in some quarters as "blackmail" - is that Russia hopes that in the event of ISS proceeding well, modules from Mir can be transferred to the ISS, saving it money by producing new research modules to be launched on to the ISS later.

On 12 November, the Russian Space Agency conceded that it had left it too late to change plans, therefore avoiding a potential delay to the STS88. The Russian move, however, has only reinforced US suspicions about its partner's intentions.

The Space Shuttle orbiter Discovery landed at the Kennedy Space Center in Florida on 7 November with former Mercury astronaut John Glenn.

Source: Flight International