A problem that struck the Hubble Space Telescope will delay the final space shuttle mission to service it, moving the launching from next month to next year, NASA officials said. A crew of seven astronauts was scheduled to blast off in the shuttle Atlantis on Oct. 14 for an 11-day visit to the telescope, which for 18 years has been beaming cosmic postcards to Earth from its orbital vantage point above the atmosphere. During five spacewalks, the astronauts were set to install two new instruments and repair the telescope's best camera and a spectrograph, both of which had electrical failures. They were also scheduled to replace the telescope's batteries and gyroscopes, among other things. But on Saturday, a channel on a control system known as the Hubble Control Unit/Science Data Formatter – which helps relay data to the ground – failed, causing the telescope to go into a “safe mode” and cease observations. Hubble's managers expect that activating a backup channel will restore the telescope to service later this week. But that will leave the telescope with no backup if the new channel stops working, so NASA would like to have the astronauts replace the failed control unit with a spare from the Goddard Space Flight Center. In a telephone news conference with reporters on Monday evening, Preston Burch of Goddard, Hubble's program manager, said the control unit hangs, attached by 10 bolts, on the inside door of a bay that the astronauts can access easily. With luck, it could be exchanged during a two-hour spacewalk, he said. “We think it's a relatively straightforward activity.” It is too soon to tell, the mission managers said, whether replacing the control unit will bump another activity from the servicing schedule. The mission's five spacewalks are tightly packed with activities, but the lead astronaut, John M. Grunsfeld, has been able in training to complete the camera repair in one spacewalk instead of the scheduled two. “This may be a doable thing, that we can have our cake and eat it too,” Mr. Burch said. Understanding what went wrong, testing the spare unit, integrating its installation into the mission schedule and training the crew to install it will take several weeks or more, Mr. Burch said. The Hubble mission cannot be launched until another shuttle, the Discovery, which is scheduled for a Feb. 12 trip to the space station, is ready to serve as the backup rescue shuttle. As a result, the flight will not take place before February 2009. The Hubble telescope, which was carried into orbit by the Space Shuttle Discovery in April 1990, is named for the American astronomer Edwin Hubble. Although not the first space telescope, the Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. Hubble's position outside the Earth's atmosphere allows it to take extremely sharp images with almost no background light. Hubble's Ultra Deep Field image, for instance, is the most detailed visible-light image of the universe's most distant objects ever made. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.
