Hubble Space Telescope goes into safe mode due to failed gyro; Plan B pending
The Hubble Space Telescope gets its final close-up after a shuttle servicing mission in 2009. (NASA Photo)
The 28-year-old Hubble Space Telescope is temporarily out of service, due to the failure of one of its gyroscopic pointing devices, but scientists say they’re working on a Plan B.
In a tweet, the Baltimore-based Space Telescope Science Institute confirmed reports that Hubble scientists such as deputy mission head Rachel Osten were passing along over the weekend: One of the telescope’s four gyros had failed on Friday, which hampered the telescope’s ability to point at astronomical targets for long periods.
“Mission experts are taking steps to return Hubble to great science,” the Hubble team said in its confirming tweet, which promised further updates ahead.
The news came as a shock to the fans of the venerable space telescope, which has sent down jaw-dropping images and data to address cosmic conundrums ranging from planetary origins to the age of the universe. Hubble’s success is due in no small part to five servicing missions flown by space shuttle crews, including an initial visit in 1993 to fix the telescope’s flawed optics and a final visit in 2009 that, among other things, replaced its gyros.
Since the shuttle fleet was retired in 2011, there’s been no possibility of repairing Hubble. The telescope has been on its own, but so far, the team’s scientists and engineers have been able to work around any maintenance snags.
Osten voiced confidence that such would be the case this time as well. Here’s how she and other scientists laid out the prognosis in a series of tweets:
It’s true. Very stressful weekend. Right now HST is in safe mode while we figure out what to do. Another gyro failed. First step is try to bring back the last gyro, which had been off, and is being problematic.
— Dr. Rachel Osten (@rachelosten) October 8, 2018
Not really scary, we knew it was coming. The gyro lasted about six months longer than we thought it would (almost pulled the plug on it back in the spring). We’ll work through the issues and be back.
— Dr. Rachel Osten (@rachelosten) October 8, 2018
HST had four good gyros, until this weekend. Fingers crossed for our friends at @stsci that the third spins up! For the record, there are totally viable 2- and 1-gyro modes (yes, even 1 gyro). https://t.co/m8AilrOGF5
— Grant Tremblay (@astrogrant) October 8, 2018
*IF* the third doesn't spin back up, I wouldn't be surprised if they drop to 1 gyro mode, keeping the second as reserve. @rachelosten might know, but I imagine it's a stressful, difficult decision. Let's just hope the brilliant people at @STScI can recover the third. Stress.
— Grant Tremblay (@astrogrant) October 8, 2018
It’s not a difficult decision, @astrogrant: the plan has always been to drop to 1-gyro mode when two remain. There isn’t much difference between 2- and 1, and it buys lots of extra observing time. Which the Astro community wants desperately.
— Dr. Rachel Osten (@rachelosten) October 8, 2018
And it’s really the brilliant people @NASAGoddard who are now staffing the flight ops 24/7, and working the anomalous gyro behavior.
— Dr. Rachel Osten (@rachelosten) October 8, 2018
Astronomers have been hoping that Hubble will continue to operate long enough to cover the transition to NASA’s next-generation James Webb Space Telescope. As recently as last year, Webb was scheduled for launch in 2018, but a series of engineering setbacks and missteps has delayed liftoff until 2021 at the earliest.