Tim Furniss/LONDON
New attempts to launch Space Shuttle Endeavour STS99 on the Shuttle Radar Topography Mission (SRTM) from the Kennedy Space Center (KSC) have been further delayed to at least 11 February because of launch-related commitments at adjoining Cape Canaveral.
A possible STS99 launch on 9 February has been thwarted by the countdown demonstration test of a US Air Force Titan 4B at Cape Canaveral. The launch was scrubbed on 31 January because of "multiple violations" in weather conditions at the KSC and emergency landing sites.
The countdown went ahead despite the weather. One of two master events controller units failed a routine start-up test and would have cancelled the launch anyway. The controller will have to be replaced and this will take until at least 9 February, NASA says. The units control the orbiter's pyrotechnic devices and process the signals that separate the solid rocket boosters and external tank.
The delay to the launch of the Endeavour was the fourth time in five consecutive missions that halted countdowns have thwarted Shuttle launches. The last on-time launch was that of STS95 Discovery, carrying veteran astronaut John Glenn in October 1998.
The SRTM's observations will be cut from 10 days to nine, sacrificing 10% of the images planned to be acquired.
NASA says it wants to ensure it has time to retract the 60m (195ft)-long radar mast - the longest fixed structure to be deployed in orbit - that will be extended from the Endeavour, if a spacewalk is required. The National Imagery and Mapping Agency, the managing agency of this partly military reconnaissance mission does not want to risk losing the mast.
NASA has revealed that the Endeavour had to be checked for a fault in a main engine turbine after the discovery that a faulty unit had flown on orbiter Discovery six times. A turbine seal rejected as faulty and which should have been scrapped was installed on the Discovery, which last flew in December.
Meanwhile, NASA has cleared the STS101 Atlantis mission to the International Space Station on 13 April. The mission will ensure that the Russian control module, Zarya, is still in working order to receive the service module, Zvezda, which will not be launched until at least late July.
Zarya, and the US Unity node module, have been unmanned since an Atlantis mission last May. A considerable amount of equipment needs to be checked out, particularly the avionics unit and electrical systems on the Zarya. Some of the Zarya's batteries also need urgent replacement. The Atlantis will be the first Shuttle to fly equipped with a glass cockpit system.
Source: Flight International
