It's starting to feel like there's a space jinx.
Hot on the heels of NASA's after a gyroscope failure, the agency's Chandra X-ray Observatory has now gone into a similar protective state.
NASA announced the issue Friday, though it happened on Wednesday.
When Chandra enters safe mode, it swaps over to hardware backup units, orients its solar panels to gather maximum sunlight and points its mirrors away from the sun.
"Analysis of available data indicates the transition to safe mode was normal behavior for such an event. All systems functioned as expected and the scientific instruments are safe," NASA says.
Instruments go into safe mode to protect themselves during hardware or software failures or glitches, leaving only essential survival systems operating. The space agency is now investigating the cause of the safe-mode transition.
Chandra is designed to make X-ray observations of distant space features, including quasars, supernovas and black holes. It's part of NASA's Great Observatories program, which includes Hubble and the Spitzer Space Telescope.
As with Hubble, Chandra has long outlived its expected original mission. The observatory is now 19 years old and was originally designed to function for five years. NASA recently extended the contract to operate Chandra through at least 2024.
Chandra's move into safe mode is just one of a long list of new challenges for NASA. Besides Hubble, NASA is also grappling withon Mars, a data transmission and a this week.