The launch date for a space shuttle mission to deploy the Hubble Space Telescope has been delayed until no earlier than April 19, according to a NASA spokesman in Huntsville, Ala.
The shuttle Atlantis had been scheduled to lift the $1.4 billion telescope into orbit in March. But the launch will be delayed because of uncertainty about tests of an O-ring joint in the shuttle booster, manufactured by Thiokol in Utah.NASA says the mission "has been rescheduled for no earlier than April 19. The delay is to allow time to remove and replace the aft solid motor segment and nozzle of the right solid rocket booster."
According to the space agency, engineers decided to change the segment and nozzle because they couldn't verify that a critical joint in the booster nozzle had been properly checked for leaks at the factory.
"The factory leak check in question is absolutely necessary to assure that the joint, or the O-ring on that joint, is not defective in any way," said space shuttle director Robert Crippen.
"In this case, we believe it was necessary to replace the joint with one that has an absolutely clean bill of health."
The Hubble Space Telescope promises to be the most valuable astronomical instrument ever built, once it is placed in orbit. Designed to remain in service for 15 years or longer, the telescope is 43 feet long and 14 feet in diameter and weighs about 25,000 pounds.
It is expected to be able to detect light sources 25 times fainter than is possible with ground-based telescopes. Supposedly, it could detect light from a typical two-battery flashlight from a distance as far as from Earth to the moon, about 250,000 miles.
Objects in space will be visible with 10 times as much detail as ever before, says NASA. The telescope may even be able to detect the presence of planets around other stars, at least through indirect means such as the star wobbling because of the planets' gravity.
The Hubble telescope's entire package was completely assembled in 1985, and launch was originally scheduled for 1986. Since then, scientists have been waiting for a chance to use it.
After the Challenger shuttle's disaster - caused by the failure of an O-ring in one of the Thiokol-manufactured booster rockets - the telescope launch was delayed indefinitely. Finally, it was put on a schedule for orbit this year.