A hobbled Hubble space telescope returns to work after four days in safe mode

The Hubble Space Telescope is back at work studying the cosmos, but with somewhat diminished capacity after more than four days offline this week.

The senior orbital observatory “entered safe mode due to an onboard software bug” around 1 am PT on Sunday and officially returned to science operations at 5 pm PT on Thursday, according to NASA.

The Hubble operations team at NASA’s Goddard Space Flight Center in Maryland has determined that a coding error in a recent software update sent to the spacecraft activated safe mode. The update has been rolled back until it can be fixed, but the episode also revealed some more troubling issues with a telescope that may be showing its age.

When Hubble went into safe mode, an opening door should have closed automatically to protect the telescope and its components from any potential damage from the sun. Like human eyes, even accidentally pointing Hubble directly at the sun could cause serious damage.

The tests revealed a problem with the prime mover that powers the door. The operations team switched to a backup engine that appears to be working.

As the team prepared to return Hubble to normal science operations, an unexpected error occurred with its Wide Field Camera 3, causing the observatory to restart without it.

In essence, Hubble is now working as usual, but without its wide-angle lens. NASA said in a statement that it is working to resolve the problem.

Hubble has overcome other problems in the past. In 2018, entered an extended safe mode after the failure of a gyroscope, which is a device for measuring how fast the spacecraft is spinning. The Hubble team managed to switch to a backup gyro and get Hubble up and running after being idle for a few weeks.

Hubble is already well beyond its planned lifespan, which was set at 15 years. Now it has been in operation for more than 30 years. Ideally, NASA would like to see it last at least a little longer until the deployment of its successor, the next-generation James Webb Space Telescope.

The James Webb Telescope has been delayed several times, but is now ready to launch this Halloween.

Get well soon, Hubble!

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