After more than a month in safe mode, NASA's Hubble Space Telescope is back online. The iconic observatory halted operations on June 13, 2021, due to a payload computer malfunction.
Hubble entered safe mode on June 13, 2021, following a failure in its Science Instrument Command and Data Handling (SI C&DH) unit, which manages the telescope's scientific instruments. Restart attempts on the primary and backup computers failed, prompting deeper diagnostics.
Engineers pinpointed the issue to the Power Control Unit (PCU), which regulates voltage for the payload computer and memory. A secondary protection circuit monitors voltage levels; if they deviate from safe parameters, it shuts down operations to prevent damage.
Analysis suggests either the voltage regulator failed, triggering the protection circuit, or the circuit itself degraded over time and locked in a shutdown state.
Unable to reset the primary PCU remotely, the Hubble team activated the backup unit on July 15, 2021. The backup system went live the next day, with all scientific instruments reactivated on July 17. Observations will resume post-calibration.
"I am proud of the Hubble team. Current and former members stepped up with their expertise," said NASA Administrator Bill Nelson. "Thanks to their dedication, Hubble will continue its 31-year legacy of expanding our view of the universe."
With groundbreaking contributions like evidence of the universe's accelerating expansion, experts are optimistic Hubble can operate until 2030.
