The Hubble Space Telescope is facing a new technical challenge, the latest in a series of issues that have thrown the aging observatory off its game in recent years.

“Hubble’s science instruments went into safe mode on Monday after experiencing synchronization issues with internal spacecraft communications,” NASA tweeted. “Science observations have been temporarily suspended while the team investigates the issue. The instruments remain in good health.”

Safe mode is designed to keep the telescope stable and allow it to remain powered via its solar panels while its team works through whatever technical problem is bothering it. 

The space observatory experienced a tense technical issue earlier this year that left it in safe mode for a month as NASA worked to switch it over to backup hardware. The fix worked and Hubble got back to business, but there’s no escaping the fact that the telescope is over three decades old.

Hubble is a joint project from NASA and the European Space Agency. Despite the glitches, the telescope has proven to be remarkably resilient in returning to service. NASA hopes it’ll continue to operate for years even as the more powerful, next-generation James Webb Space Telescope finally takes flight in December.