Scientists announced this afternoon that the 18-year-old orbiting observatory's long-sleeping backup computer system is up and running and has started to bring the telescope back to life. The announcement comes a week after two glitches had foiled NASA's initial effort to switch to the backup system.
Art Whipple, chief of NASA's Hubble systems management office at the Goddard Space Flight Center, said in a press teleconference that although the observatory's main systems were powered up today and are running smoothly, all of the science instruments will remain in safe mode while NASA engineers gauge how the system holds up.
Whipple said the agency hoped to take the first instrument -- a camera -- out of safe mode on Saturday. A major scientific instrument, the Advanced Camera for Surveys, should be taken out of safe mode next week, he added.
Scientists were stymied last week when the two glitches blocked their attempts to get the Hubble back in working order after a computer responsible for sending data back to Earth failed late last month. On Oct. 15, a NASA team first tried to complete a remote switchover from the failed system to an on-board redundant system.
Initial tests a day later showed that the backup system was working well, but the observatory's activation was suspended after they ran into two "anomalies," as described by Whipple in a previous press conference.
Today, Whipple called the cause of at least one of the two glitches a "transient" event that likely stemmed from the fact that they were firing up a backup system that had sat idle for 18 years while hurtling around Earth at 17,500 mph. "The system had been powered off for a long time. We may see more events in the future," he added. "There doesn't appear to be any permanent damage."
The telescope, which has made more than 100,000 trips around Earth, is the first major optical telescope to be placed in space, NASA said. Scientists program Hubble to capture images of the planets in our own solar system, as well as images of far-off stars and galaxies.
This is the first Hubble computer malfunction that has required the installation of a replacement system. "There's nothing young in the system," said Michael Moore, a program executive for the Hubble Space Telescope.
The initial problem lay in the Science Data Formatter, which is designed to take information from five onboard instruments, format it into data packets, put a header on it and then send it to Earth at speeds of up to 1Mbit/sec. Without this computer, Hubble can't take on long-planned research projects.
A planned October space shuttle mission to the telescope, which is the length of a large school bus and weighing 24,500 lbs., was postponed so that scientists can ready another system to be brought up and installed as the next redundant system. As of last week, John Shannon, shuttle program manager at the Johnson Space Center, said the flight will likely be rescheduled for February or April of next year.