Engineers had hoped to have the back in working order Friday after a computer responsible for sending data back to Earth . On Wednesday, a NASA team did from the failed system to an on-board redundant system.
Initial tests showed that the backup system was working well, but the observatory's activation was suspended after they ran into two "anomalies", said Art Whipple, chief of NASA's Hubble systems management office at the , in a press conference late Friday.
Whipple said he could not yet pinpoint the specific problems. "We are in the early stage of going through a mountain of data that's been downloaded over the last 24 hours," Whipple said. "We're fairly certain it was not a configuration error. We are not to the point where we can rule out either transient issues or, for that matter, hard failures. We're just not there yet."
He explained that the problem first surfaced when engineers were switching science instruments from safe mode to operation mode. During the final stages of ramping up the Advanced Camera for Surveys, they detected an incorrect voltage level and suspended the move. Several hours later, the Hubble's main computer detected the loss of a signal from another onboard system and put the science instruments back in safe mode. NASA noted that no one is sure yet if the two incidents are related.
Whipple said that at this point he estimates late next week as the soonest the space telescope would be fully operational. "There's a lot of analysis to be done. A lot of data to go through," he said.
The telescope, which has made more than 100,000 trips around Earth, is the first major optical telescope to be placed in space, NASA says. Scientists program Hubble to capture of the planetsin our own solar system, as well as and .
This is the first Hubble computer malfunction that has required the installation of a replacement system. "There's nothing young in the system," said , a program executive for the Hubble Space Telescope.
The 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.
Ed Weiler, associate administrator of the Science Mission Directorate at NASA, has noted before that the switchover and subsequent installation of new redundant systems should add another five to 10 years to the Hubble's life.