Over 10 days after the Hubble Space Telescope went dark in space and suspended science operations, engineers are trying to isolate the problem to get the flying observatory out of safe mode. The spacecraft remains in safe mode since October 25 after it glitched beyond Earth’s orbit for the second time within six months.

The spacecraft entered safe mode after detecting a loss of specific data synchronisation messages.

“The Hubble team is focusing its efforts to isolate the problem on hardware that commands the instruments and is part of the Science Instrument Command and Data Handling Unit,” Nasa said in a statement. Engineers are looking at the circuitry of the power unit that generates synchronization messages and passes them onto the instruments.

The Hubble Space Telescope, which recently completed 30 years of service beyond Earth’s orbit, was first launched in 1991. The observatory has been key in some of the most significant discoveries of our cosmos, including the accelerating expansion of the universe, the evolution of galaxies over time, and the first atmospheric studies of planets beyond our solar system.

What happened?

The multi-million dollar spacecraft that has been our window into the vastness of the cosmos first issued error codes indicating the loss of a specific synchronization message on October 23. The message is used by Hubble to provide timing information that the instruments use to correctly respond to data requests and commands.

When the first error message reached mission control, engineers reset the instrument to resume science operations. However, the telescope went into safe mode on October 25 after the science instruments again issued error codes indicating multiple losses of synchronisation messages. The telescope team said, “the science instruments then autonomously entered a safe mode state as programmed.”

Looking for a fix

As engineers analyse the power unit of the spacecraft, they are trying to identify potential workarounds for the issue. Nasa said that it is looking at possible changes to 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 they work as planned.

The Hubble team turned on parts of the Near Infrared Camera and Multi Object Spectrometer (NICMOS) instrument to collect data on this issue, allowing the team to determine how frequently this problem occurs. The team was able to recover the instrument and collect information on these lost messages while keeping the active instruments off as a safety precaution.

The team is now taking steps to recover Hubble’s Advanced Camera for Surveys (ACS) instrument from safe mode and start collecting science with that instrument at the beginning of next week. Engineers are trying to recover the spacecraft without putting additional stress on the already aged machine.

“Over the next week, the team will continue analysing the Control Unit design diagrams and data associated with the lost messages to determine what may have caused this problem. They will also be looking into potential instrument software changes that could help address it,” the US space agency added.

Hubble had faulted in June earlier this year as well that led to a month-long shutdown, owing to a faulty payload computer onboard Hubble that coordinates science operations. When the main computer failed to receive a signal from the payload computer on June 13, it automatically placed Hubble’s science instruments into safe mode, making it blind in space.