WASHINGTON — NASA is taking a slow and deliberate approach to restoring operations of the Hubble Space Telescope, which has been out of service since mid-June when a payload computer malfunctioned.
Hubble stopped science operations on June 13 when the payload computer, which runs the telescope’s instruments, malfunctioned. An initial investigation suggested the problem was with a faulty memory module, but switching to a backup memory module failed to correct the problem.
In a June 30 update, NASA said engineers are now focusing on an electronics unit called the Command Unit/Science Data Formatter, which formats and transmits commands and data, as well as a power regulator. While both have backups, switching to them is a complex process because of how they’re connected to the overall payload computer system.
“Over the next week or so, the team will review and update all of the operations procedures, commands and other related items necessary to perform the switch to backup hardware,” NASA stated in the update. Testing in “a high-fidelity simulator” will follow before attempting the switch on Hubble itself.
The long interruption in science operations by Hubble has fueled public concern and speculation that the problem with the venerable space telescope is more serious and possibly irreparable. However, agency officials have said they are simply making sure they don’t do anything to make the problem worse.
“I have given the Hubble team very clear direction that returning Hubble safely to service and not unintentionally doing any harm to the system is the highest priority, not speed,” Paul Hertz, director of NASA’s astrophysics division, said at a June 29 “meeting of experts” held in a place of an Astrophysics Advisory Council meeting that had been scheduled for that day.
“They’re being very deliberate in their analysis and their choices of what they do,” he said. “There’s two layers of review of all the procedures they come up with.”
While the payload computer is offline, the spacecraft itself is working normally. Hertz said that Hubble is continuing to carry out programmed observations in order to maintain power and thermal control, although without the payload computer it can’t collect any data.
Hertz didn’t give a timeline for correcting the problem, but when one astronomer asked if it would take weeks or months, he responded, “Weeks.”
“Although we’re all impatient to have Hubble back taking science, the highest priority is to be very careful and deliberate and not rush,” he said.