WASHINGTON – NASA’s Hubble Space Telescope resumed observations on March 11 after a software bug placed it in a protective safe mode several days earlier, but the incident recalls the telescope’s death.
NASA said Hubble resumed observations at 8:00 p.m. on March 11 on March 11, more than four and a half days after a software glitch caused the spacecraft to enter a safe mode and halt the normal operations of the nearly 31-year-old space telescope.
The software bug was traced to what an agency statement called an “improvement” recently uploaded to the spacecraft. That improvement was intended to compensate for swings from one of the telescope’s gyroscopes, but a software glitch caused a bigger problem with Hubble’s main computer, triggering safe mode early March 7.
Controllers have provisionally solved the problem by disabling that software enhancement, and plan to correct the bug and further test the new software before uploading it again.
However, that safe mode caused two other problems with Hubble. The telescope’s opening door, a lid on top of the telescope, is designed to automatically close when the spacecraft enters safe mode to prevent stray light from entering, which can damage instruments and optics. During this safe mode, however, the door wouldn’t swing shut, a problem never seen with Hubble before.
Engineers who fixed the problem found that the door closed as soon as they switched to a spare engine. They have now set that motor as the primary motor while continuing to study the problem with the other motor.
One of Hubble’s tools, the Wide Field Camera 3, “encountered an unexpected error” while recovering from safe mode. NASA did not elaborate on the error, but said observations with that instrument will remain on hold while engineers study the problem. The spacecraft’s other instruments, including a camera and two spectrographs, are working.
Safe mode and related issues remind us of Hubble’s age. The spacecraft was launched in April 1990 and serviced by the space shuttle five times, most recently in May 2009. With the shuttle long-retired, astronomers know that at some point Hubble will undergo an irreparable failure that will put an end to it. its historic mission.
“Right now, we’re in the middle of what I think is a really good news story about Hubble,” Jennifer Wiseman, an astronomer at NASA’s Goddard Space Flight Center, said at a conference on the space telescope last year. They and others believe the telescope could remain operational for much of this decade, based on trends in the performance of key components, such as the gyroscopes and batteries.
Some have advocated a new service mission to Hubble using a robotic or manned spacecraft. John Grunsfeld, a former NASA astronaut who flew on three Hubble service missions and later served as the science bureau’s associate administrator, last year presented a concept for a manned service mission using an Orion spacecraft and a module equipped with a robotic arm and an airlock. That spacecraft would dock with Hubble, after which astronauts would make repairs, just like on previous service missions.
“We have the technology to go back to Hubble,” he said in a presentation to the Space Transportation Association last June, noting that a commercial crew vehicle, such as Crew Dragon, could be used in place of Orion. “We could keep Hubble running for a few more decades.”
However, NASA has shown no public interest in such a service offering, which would cost hundreds of millions to billions of dollars. It’s not in the books right now. Nobody really talks about it much, at least in public, ”admitted Grunsfeld.
Without a service mission, Hubble could take many years, or fail tomorrow, astronomers like Wiseman acknowledge. “We don’t know how long Hubble will last,” she said.