NASA has restored the work of "Hubble"
On March 12, 2021, NASA announced that the Hubble telescope was fully operational. The Space Lab has returned to research mode. The telescope went into safe mode on March 7 due to a bug in the onboard software.
It turned out that the emergency on the telescope was due to a recently installed software update that was supposed to compensate for the vibrations of one of its gyroscopes. This patch did not have permission to write to a specific place in the on-board computer memory, which caused an error in its operation and subsequently forced the entire system to go into safe mode.
NASA specialists updated Telescope software and disabled the problematic update. After performing these works and remote monitoring in the safe mode of the telescope systems, NASA discovered a problem with the aperture hatch (protective flap) located at the top of the telescope - it did not close automatically. This hatch is a protective device designed to prevent harmful sunlight and heat from entering the telescope, protecting its sensitive instruments and their environment. This protective mechanism acts as a safety net if the Hubble accidentally turns in the direction of the Sun due to an error or hardware malfunction. In more than 30 years of Hubble's in orbit, the aperture hatch has never been closed due to the detection of such bright objects.
NASA examined the telescope logs, conducted various tests that confirmed that the hatch did indeed remain open, despite the necessary control commands sent to close it. Onboard sensors indicated that the system was transmitting enough power to carry out these actions. Additional attempts to move the hatch, sending commands from the ground to its main engine, also failed to close it. Then NASA specialists sent the same commands to its backup engine. And it worked. This engine is now installed as the main engine. A NASA team is investigating the causes of the main engine failure.
On March 11, NASA specialists successfully restarted the main systems of the telescope, including the Cosmic Origins Spectrograph (COS) spectrograph.
NASA clarified that in the process of recovering from a software error in the main on-board computer of the telescope, specialists also encountered other power problems, for example, the Wide Field Camera 3 (WFC3) stopped turning on due to an internal protection triggering - the telescope systems issued a reduced voltage for the power source this appliance. This problem was also promptly resolved by NASA.
NASA analysis found that the voltage levels in the WFC3's power supplies slowly declined over time as its electronics age. Moreover, the camera electronics were exposed to lower temperatures when the telescope was put into safe mode. This factor, coupled with the increased power consumed by the instrument components when turned on again, contributed to a slight voltage fluctuation that stalled the WFC3's recovery operations. Further investigation of the problem has shown that it is safe to programmatically lower the low voltage limit slightly to avoid turning off the camera in the future. NASA is currently busy with WFC3 calibration and preliminary checks.
On March 7, 2021, NASA reported about a problem with the software of the Hubble telescope, due to which it went into safe mode.
The Hubble telescope was launched into Earth orbit in April 1990 by NASA and the European Space Agency aboard the space shuttle Discovery.
In 2018, the Hubble went into safe mode due to a problem with two gyroscopes for orientation in space. NASA specialists fixed the problem after 3 weeks.