NASA’s Hubble Space Telescope is back in business, exploring the universe near and far. The science instruments have returned to full operation, following recovery from a computer anomaly that suspended the telescope’s observations for more than a month.
Science observations restarted the afternoon of Saturday, July 17. The telescope’s targets this past weekend included the unusual galaxies shown in the images below.
“I’m thrilled to see that Hubble has its eye back on the universe, once again capturing the kind of images that have intrigued and inspired us for decades,” said NASA Administrator Bill Nelson. “This is a moment to celebrate the success of a team truly dedicated to the mission. Through their efforts, Hubble will continue its 32nd year of discovery, and we will continue to learn from the observatory’s transformational vision.”
These snapshots, from a program led by Julianne Dalcanton of the University of Washington in Seattle, feature a galaxy with unusual extended spiral arms and the first high-resolution glimpse at an intriguing pair of colliding galaxies. Other initial targets for Hubble included globular star clusters and aurorae on the giant planet Jupiter.
Hubble’s payload computer, which controls and coordinates the observatory’s onboard science instruments, halted suddenly on June 13. When the main computer failed to receive a signal from the payload computer, it automatically placed Hubble’s science instruments into safe mode. That meant the telescope would no longer be doing science while mission specialists analyzed the situation.
The Hubble team moved quickly to investigate what ailed the observatory, which orbits about 340 miles (547 kilometers) above Earth. Working from mission control at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as well as remotely due to COVID-19 restrictions, engineers collaborated to figure out the cause of the problem.
Complicating matters, Hubble was launched in 1990 and has been observing the universe for over 31 years. To fix a telescope built in the 1980s, the team had to draw on the knowledge of staff from across its lengthy history.
Hubble alumni returned to support the current team in the recovery effort, lending decades of mission expertise. Retired staff who helped build the telescope, for example, knew the ins and outs of the Science Instrument and Command & Data Handling unit, where the payload computer resides – critical expertise for determining next steps for recovery. Other former team members lent a hand by scouring Hubble’s original paperwork, surfacing 30- to 40-year-old documents that would help the team chart a path forward.
On June 13, 2021, the Hubble Space Telescope’s payload computer unexpectedly came to a halt. However, the Hubble team methodically identified the possible cause and how to compensate for it. Credit: NASA’s Goddard Space Flight Center
“That’s one of the benefits of a program that’s been running for over 30 years: the incredible amount of experience and expertise,” said Nzinga Tull, Hubble systems anomaly response manager at Goddard. “It’s been humbling and inspiring to engage with both the current team and those who have moved on to other projects. There’s so much dedication to their fellow Hubble teammates, the observatory, and the science Hubble is famous for.”
Together, team members new and old worked their way through the list of likely culprits, seeking to isolate the issue to ensure they have a full inventory for the future of which hardware is still working.
At first, the team thought the likeliest problem was a degrading memory module, but switching to backup modules failed to resolve the issue. The team then designed and ran tests, which involved turning on Hubble’s backup payload computer for the first time in space, to determine whether two other components could be responsible: the Standard Interface hardware, which bridges communications between the computer’s Central Processing Module and other components, or the Central Processing Module itself. Turning on the backup computer did not work, however, eliminating these possibilities as well.
The team then moved on to explore whether other hardware was at fault, including the Command Unit/Science Data Formatter and the Power Control Unit,…