The Hubble Space Telescope photographed in 2009 at the end the last servicing mission.
NASA is looking at software changes to the Hubble Space Telescope in its ongoing effort to restore the telescope to service.
In an update on Friday, Nov. 5, the agency stated that the recovery team is currently examining hardware which commands the instruments. This hardware forms part of Science Instrument Command and Data Handling Unit. Since its instruments entered a protective mode in October, the iconic space telescope was unable to make science observations.
NASA said that the NASA team was analyzing the circuitry in the Control Unit which generates synchronization signals and sends them to the instruments. NASA is looking at changing the instrument flight software in order to search for data sync messages without having to go into "safe mode". According to the agency, the glitch was caused by the loss of these messages.
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After a glitch in the telescope's operation, it was put into safe mode and is now able to perform observations. The telescope has been in space since 1990. The agency provided an update on Tuesday (Nov. 2) stating that all instruments are in good health and the investigation is continuing.
It is not planned to be repaired in-person as the space shuttles used to fly to the telescope to repair it were retired after 30 years of operation. Hubble is being assisted by investigators from afar. NASA said that any workarounds should first be tested using ground simulators in order to verify they work as expected.
Software changes will occur if necessary after the Hubble team examines control unit design diagrams and data from lost messages. They also consider the possible instrument software changes that might be made to address the problem.
Hubble team members are also trying to gather data from the observatory’s instruments and cameras. NASA said that the NASA team activated parts of the Near Infrared Camera (NICMOS), which "allows the team to determine the frequency this [data synchronization] issue occurs." The update stated that NICMOS had been recovered Monday (Nov. 1), and no data synchronization messages have been lost since then.
Next, Hubble engineers will be working to recover Hubbles Advanced Camera for Surveys(ACS) instrument. The goal is to start collecting science again in the first week of next week. After the agency has analyzed the data, a final decision will be made on Sunday (Nov. 7). NASA stated that ACS was the best instrument to test first because it is less likely to cause stress to the observatory.
NASA stated that ACS activation will be re-considered if a lost message is detected before then. It also noted that the plan to return instruments to full service is still being developed. The agency stated that the team was proceeding cautiously to protect the instruments and minimize stress on the hardware.
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