NASA successfully transitioned operations for the agency’s Hubble Space Telescope to an alternate operating mode that uses one gyro, returning the spacecraft to daily science operations Friday. The telescope and its instruments are stable and functioning normally.

Hubble went into safe mode May 24 due to an ongoing issue with one of its gyroscopes (gyros), which measure the telescope’s slew rates and are part of the system that determines and controls the direction the telescope is pointed. The gyro had been increasingly returning faulty readings over the past six months, suspending science operations multiple times. This led the Hubble team to transition from a three-gyro operating mode to observing with only one gyro, enabling more consistent science observations and keeping another operational gyro available for future use. The agency discussed this transition in detail during a media teleconference June 4.

The team will continue monitoring the problematic gyro to see if it stabilizes and can be used again in the future. Although there are some minor limitations to observing in one-gyro mode, Hubble can continue doing most of its science observations. Further refinements to optimize operations are anticipated as the team gains more experience with the one-gyro mode.

Launched in 1990, Hubble has more than doubled its expected design lifetime, and has been observing the universe for more than three decades, recently celebrating its 34th anniversary. Read more about some of Hubble’s greatest scientific discoveries.

Originally Published May 31, 2024

NASA’s Hubble Space Telescope entered safe mode May 24 due to an ongoing gyroscope (gyro) issue, suspending science operations. Hubble’s instruments are stable, and the telescope is in good health.

The telescope automatically entered safe mode when one of its three gyroscopes gave faulty telemetry readings. Hubble’s gyros measure the telescope’s slew rates and are part of the system that determines and controls precisely the direction the telescope is pointed. NASA will provide more information early the first week of June.

NASA anticipates Hubble will continue making discoveries throughout this decade and possibly into the next, working with other observatories, such as the agency’s James Webb Space Telescope for the benefit of humanity.

Launched in 1990, Hubble has been observing the universe for more than three decades and recently celebrated its 34th anniversary. Read more about some of Hubble’s greatest scientific discoveries.

Media Contact:

Claire Andreoli
NASA's Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov