NASA must be feeling the pressure, given the ongoing delays in launching the space shuttle Discovery on its Hubble Space Telescope repair mission.
The shuttle is now due to lift off from the Kennedy Space Centre this Thursday. It had been due for launch on December 9th, and this latest delay is only one of a series going back nearly six weeks.
The success of the mission is crucial given the fact that the world's single most effective telescope, which orbits the Earth high above the interference caused by our atmosphere, has been out of commission since November 13th.
The Hubble Space Telescope has given us remarkable views of our solar system and unparalleled images from distant galaxies. Now, however, it is "parked" after the failure of its gyroscopes which allow the telescope to be targeted with great accuracy.
Unfortunately, the servicing mission goes ahead against a backdrop of failure in NASA's Mars research programme. Last September its Mars Polar Orbiter crashed spectacularly after miscalculations caused when one set of scientists worked in British units while another team used metric.
Then, just over a week ago, its Mars Polar Lander disappeared without trace as it began its descent for a soft touchdown on Mars. Repeated attempts to establish radio contact with the satellite came to nothing and the Lander was presumed lost.
NASA can't afford the publicity of yet another failure, despite its many successes in the past. These include, perhaps most notably, the Mars Pathfinder, the little shoebox on wheels that scooted over the Martian surface last year and sent back live pictures. NASA is probably being extra cautious about the flight to repair the telescope, an enormously complex mission. The seven-person crew, which includes two Europeans, is due to carry out a comprehensive refit.
This third servicing mission was meant to take place next year but was brought forward because of the failing gyros. The research team realised the gyros weren't going to last long enough for the planned service, so a shuttle flight was rearranged to allow running repairs. That didn't get there in time, however, to prevent the telescope's shutdown.
If the repairs don't succeed, it will remain out of action for some time. The next service wasn't meant to happen until 2001.
