Greenbelt, Maryland – NASA continues work to resolve an issue that has suspended scientific operations on the Hubble Space Telescope. Scientific instruments entered a safe mode configuration on October 25, 2021 after detecting a loss of specific data sync messages.
The Hubble team is focused on isolating the problem on the hardware that controls the instruments and is part of the Science Instrument Command and Data Handling Unit. Specifically, the team analyzes the circuitry of the control unit, which generates synchronization messages and transmits them to the instruments.
When analyzing the control unit, the team strives to identify potential workarounds to the problem. These include possible modifications to the instrument flight software that could check for these lost messages and compensate for them without putting the instruments into safe mode. These workarounds would first be verified using ground simulators to ensure that they function as intended.
Over the weekend of October 30, the team prepared to activate parts of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to collect data on this issue, allowing the team to determine how often this problem occurs.
Installed in 1997, NICMOS has been inactive since 2010, when the Wide Field Camera 3 became operational. NICMOS allowed the team to use an instrument to collect information about these lost messages while keeping the active instruments powered off as a safety measure. Since NICMOS was recovered on November 1, no additional sync messages have been lost.
The team is now taking steps to recover Hubble’s Advanced Camera for Surveys (ACS) instrument from Safe Mode and start collecting scientific data with this instrument early next week. The team will make the decision on Sunday after analyzing the latest data. If a lost message is seen before this date, the decision to activate ACS will also be reconsidered. The team proceeds with caution to ensure the safety of the instruments and to avoid additional strain on the equipment.
Therefore, only ACS will be used in this capacity next week. The ACS was selected as the first instrument to be recovered because it faces the least complications in the event of message loss.
Over the next week, the team will continue to analyze control unit design diagrams and data associated with lost messages to determine what may have caused this issue. They will also look at potential changes to the instrument’s software that could help remedy this.
Once the team better understands the frequency of the problem and has determined how long it will take to implement any software changes, they will discuss a plan to return the other instruments to science operations.