Legendary space observatory Hubble is back in action

Nearly 34 years after its launch aboard NASA’s Space Shuttle Discovery in 1990, Hubble continues to provide valuable scientific data for astronomers. However, since late November, the Hubble Space Telescope has been out of use due to a gyroscope malfunction. After making intense efforts to save the space observatory, NASA announced in a statement last Friday that Hubble had restarted its activities.

Hubble started working again

The Hubble Space Telescope had been experiencing a gyroscope malfunction for approximately three weeks. The problematic gyroscope is a critical part of the observatory’s pointing system, while gyroscope systems help the telescope make precise observations by measuring how fast the vehicle is rotating. NASA announced in a statement that it has now returned to telescope science operations with the gyroscope coming back into use.

With five shuttle missions so far, NASA has repaired Hubble, upgraded science instruments and replaced hardware that had failed due to long-term use in space. Among other missions, during the last shuttle repair flight in 2009, astronauts installed six new gyroscopes on Hubble.

Moving parts break down

Gyroscopes, on the other hand, have long been one of Hubble’s most maintenance-requiring parts. According to NASA, the wheel inside each gyroscope rotates at a constant speed of 19,200 revolutions per minute, and the wheel is sealed inside a cylinder suspended in a dense liquid. Electronics inside each gyroscope detect minute movements in the wheel’s axis, providing Hubble’s central computer with information about the spacecraft’s rotation rate. Hair-thin cables direct signals from gyroscopes, and these cables can deteriorate over time.

Three of the six gyroscopes installed on Hubble in 2009 failed, while the other three continue to work. The three gyroscopes currently in operation are based on a newer design for longer life, but one of these units has shown signs of wear in the last few months. Pat Crouse, Hubble project manager, said that this gyroscope, called Gyro 3, has been exhibiting slightly troublesome behavior since time immemorial.

Because Hubble typically needs three gyroscopes to operate normally, ground controllers kept Gyro 3 shut down for nearly seven years, until in 2018, another gyroscope Hubble needed malfunctioned, leaving only three of the devices operational. NASA engineers say that Hubble can work with a single gyroscope, but may have difficulties examining fast objects (such as asteroids in the Solar system).