The Hubble Space Telescope has all its scientific instruments back online. Following a worrying month trying to get the veteran observatory to work again, NASA approved a daring approach last week. Over the course of several days, the solution worked, and the ground team was able to slowly get the telescope completely back online.
NASA reported a malfunction on June 13 when Hubble’s payload computer stopped working. A month later, it was announced that the secondary protection circuit of the Power Control Unit (PCU) was either getting voltage levels beyond the acceptable level (this might have been true, suggesting the fault was elsewhere) or had degraded so much that is stuck in this safety mode. Attempts at getting the PCU to restart were unsuccessful.
Most of Hubble’s hardware is double so if one fails, there’s a backup. It’s not ideal to move to the backup as then you don’t have one anymore, but desperate times call for desperate measures, and the mission team planned to move everything on the backup side of the Science Instrument Command and Data Handling (SI C&DH) unit.
Several tests took place in preparation for this switch. They were all successful, and the space agency gave the go-ahead to actually attempt the switch. Once that was successful, the time came to slowly take the scientific instruments out of their safe mode configuration – an operation that has been now completed successfully.
“Hubble is an icon, giving us incredible insight into the cosmos over the past three decades,” NASA Administrator Bill Nelson said in a statement. “I’m proud of the Hubble team, from current members to Hubble alumni who stepped in to lend their support and expertise. Thanks to their dedication and thoughtful work, Hubble will continue to build on its 31-year legacy, broadening our horizons with its view of the universe.”
This was not the first time that such a switch to backup was done on Hubble – the precedent was back in 2008. The difference then was that the whole SI C&DH was then replaced in 2009, during the last Space Shuttle mission to service Hubble. With no Space Shuttle, there are no more servicing missions. Although that is a concern, NASA believes Hubble has still several years of work ahead.
Hubble has completed its 31st birthday in orbit, and in that time, it has snapped over 1.4 million observations of the universe. Its incredible work has been used in over 18,000 scientific papers and truly changed our understanding of the cosmos forever. Long may it keep its watchful eye on the heavens.