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NASA Transitions Hubble Space Telescope to One-Gyro Operation Amidst Ongoing Challenges

In a strategic move to extend the operational life of the Hubble Space Telescope, NASA announced on Tuesday that the telescope will transition to using only one gyroscope (gyro).

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Zac Aubert

Zac Aubert

Tue Jun 04 2024Written by Zac Aubert

In a strategic move to extend the operational life of the Hubble Space Telescope, NASA announced on Tuesday that the telescope will transition to using only one gyroscope (gyro).

The decision comes after extensive testing and careful consideration of the options available to address recurring issues with one of Hubble's gyros. Currently, the telescope is in safe mode, a precautionary state it entered on May 24, and will remain there until the transition is complete. T

his adjustment is aimed at ensuring that Hubble continues to explore the secrets of the universe well into the next decade, with minimal impact on the majority of its observations.

The Hubble Space Telescope, launched in 1990, originally came equipped with six gyros to measure its slew rates and help control its pointing direction. Of these six gyros, three remain active. However, over the past six months, one gyro has been returning faulty readings with increasing frequency. This issue has forced the telescope into safe mode multiple times, halting scientific observations while awaiting further instructions from the ground.

The problematic gyro is experiencing what is known as “saturation,” where it registers the maximum slew rate regardless of the actual speed of the spacecraft’s movements. Although NASA’s team has managed to reset the gyro’s electronics to temporarily restore normal readings, the problem has consistently resurfaced, most recently in late May.

To address this, NASA has decided to shift Hubble to a one-gyro operational mode, a strategy that has been in development for over 20 years. This mode not only prolongs the telescope’s lifespan but also ensures it can continue providing valuable scientific data with fewer than three working gyros.

Hubble had operated in a similar two-gyro mode from 2005 to 2009, and one-gyro operations were successfully demonstrated in 2008 without any significant impact on the quality of science observations.

“Hubble will operate with only one gyro, while keeping another gyro available for future use,” - NASA

This change requires reconfiguring both the spacecraft and its ground systems, as well as evaluating the impact on upcoming planned observations. Despite the transition, NASA expects to resume scientific operations by mid-June.

Operating in one-gyro mode will introduce some minor limitations. The observatory will need more time to slew and lock onto a target and will have less flexibility in terms of observational positions. Additionally, it will no longer be able to track moving objects closer than Mars, although these targets are rare for Hubble.

Despite these challenges, NASA remains optimistic about Hubble’s future. The telescope, which celebrated its 34th anniversary this year, has significantly outlived its original expected design lifetime and continues to make groundbreaking discoveries. Once Hubble is back to conducting scientific observations, it will work in tandem with other advanced observatories, such as the James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope.