Tuesday, October 5, 1999 Published at 12:03 GMT 13:03 UK
Space Station delayed again
The ISS will cost tens of billions of dollars
By BBC News Online Science Editor Dr David Whitehouse
US and Russian space officials have postponed the launch of the next component of the International Space Station (ISS) by at least several weeks.
Officially Nasa and the Russian Space Agency are aiming for a launch between 26 December and 16 January but many experts think that even this date will slip.
Nasa officials say that such delays are to be expected in the construction of the largest and most complicated structure ever built in orbit, especially when two major partners, one of whom has severe economic problems, are constructing it.
Curiously, the Russian delay lets Nasa off the hook as well. The software for their next space station component requires more testing and the delay will allow them to do that.
Both sides have decided to take advantage of the delays created by Nasa's decision to ground the space shuttle fleet after wiring defects were detected during Columbia's mission in July.
The 43-foot-long Zvezda module will be the living quarters and life support equipment for the three-member crews of astronauts and cosmonauts that are due to take up residence next spring.
The latter date proposed will also allow favourable lighting conditions for the automated docking between the new module and the other parts of the space station.
The docking will now take place over Asia where there is radio contact between Russian ground stations and all of the orbiting components. That particular part of the orbit would have been in darkness between November and early December, hampering live television views of the rendezvous and docking activities from cameras on the new module.
Another reason why both sides wanted a delay is the space shuttle Atlantis. It had been scheduled to follow Zvezda into orbit in early December to deliver supplies for future station crews.
But Shuttle flights were suspended following Columbia's July mission when the electrical wiring problem found was seen in all space shuttles.
Following repair work, Discovery should be ready to launch in November on a high priority mission to replace failing gyroscopes on the Hubble Space Telescope. Endeavour could be ready in December to carry a large radar apparatus to map the Earth's surface.
Repair work on Atlantis did not begin until last week so it is unlikely that it would have been ready for its planned February mission to the space station.
However, the station's first resident crew could be launched as soon as March.