A repair mission by the space shuttle was scheduled to take off months ago, but has been delayed several times. Now astronauts say their ability to bring their craft near the telescope and repair it is under threat. ``Instead of looking at (Hubble) end-on, we will be looking at it from the side or from the top,' said Curt Brown, commander of the shuttle Discovery, which will take off on 6 December.

NASA has been struck by a series of recent bungles, but is putting a brave face on the threat to Hubble, which has provided the agency with superb publicity. Reams of photographs of star clusters and dusty nebulae have been sent back by the telescope, which can view the universe with unrivalled clarity from outside Earth's atmosphere.

But Hubble - and the shuttle - are showing signs of age. Several recent shuttle launches have been postponed, some within seconds of take-off. Most recently, a drill bit was found inside a main engine, a potentially lethal mistake.

The giant telescope was fitted with six gyroscopes to maintain its position in orbit, but by early 1999 only three the minimum needed to run the observatory were still working. Two weeks ago, a fourth failed. As a result the telescope can no longer be pointed accurately. The agency says Hubble is parked in a `safe orbit' and will be repaired, but Discovery's astronauts are not so sure.

Without gyroscopes, Hubble is drifting out of alignment. When the shuttle reaches it, the telescope is likely to be in an unsuitable position to be hauled into the spaceship's repair bay. It is unclear whether the astronauts will be able to overcome this problem. The 10-day repair mission is complex, involving four two-man spacewalks that will push the crew to the limits of their endurance. This new crisis threatens their chances of success. As there is no room for extra cargo in later shuttle launches, this forthcoming repair mission will determine the future of Hubble.

In addition, NASA is reeling from two other recent bungles. The Chandra X-ray observatory, costing $1b and designed to study radiation emitted by exploding stars and galaxies, has been seriously damaged because designers forgot to shield it from Earth's radiation belts. The flaw has been put right, but not before several key experiments were ruined and the spacecraft's usefulness degraded. In addition, a report last week revealed that inept management and poor communications were responsible for the destruction in September of NASA's $ 125m Mars Climate Orbiter probe.

Confusion over the use of imperial and metric units caused the spaceship to crash into the planet's surface. These same management flaws now threaten NASA's Mars Polar Lander, which is scheduled to land on dangerously rocky terrain on 3 December. This mission is far more demanding than the 1977 Martian Pathfinder Rover mission but has received less funds. An extra 30 engineers have been drafted in to save the mission.

Nevertheless, the landing involving a newly developed landing engine will be watched with great anxiety by agency officials.--The Observer News Service

Repair mission delayed
CAPE CANAVERAL: US Space agency NASA has delayed by three days the next mission to repair the Hubble space telescope so that the technicians can repair faulty electrical wiring on the shuttle Discovery. The launch is now set for early morning December 9, the Kennedy Space Centre said on Monday. An alternate launch window is set for December 18. The Discovery mission was originally scheduled for October but was delayed when NASA ordered wiring repairs on its entire shuttle fleet.

--DPA