The space community has had a tough time of late. In the past few months, we’ve had to deal with the news that the Dawn and Kepler spacecraft were running out of fuel, the Opportunity rover is stuck on Mars, and the Hubble and Chandra telescopes were both in trouble.
Well there’s good news on the latter front. Following the news that Chandra would recover, Hubble looks like it is following suit and should also soon return to full operations.
The issue was with one of Hubble’s gyroscopes. The telescope had three left working, from an initial six after launching in 1990, that enable it to point at distant stars. But on Friday October 5, it was found one of them wasn’t working, meaning it couldn’t orientate itself properly.
Hubble was put into safe mode while engineers investigated the issue. Without three working gyros, Hubble’s science ability would be significantly reduced, although it could still perform astronomy – albeit somewhat limited – with a single gyro.
NASA noted in an update that a wheel inside the gyro is designed to spin at a rate of 19,200 revolutions per minute. But engineers were getting back “extremely high rotation rates”, causing the telescope to enter safe mode.
In classic fashion, engineers tried to solve the issue by turning the gyro on and off again on October 16. This didn’t work, but on October 18, they commanded the telescope to turn “in opposite directions” to clear any blockage in the gyro.
By switching the gyro from high mode to low mode, this seems to have fixed the gyro. After these maneuvers, the gyro stopped spinning at its incorrect rate. As of October 19, the gyro was back to normal.
“Hubble then executed additional maneuvers to make sure that the gyro remained stable within operational limits as the spacecraft moved,” said NASA. “The team saw no problems and continued to observe the gyro through the weekend to ensure that it remained stable.”
Engineers will now perform additional tests to make sure it is working properly. But all signs look good at the moment. After the tests, “Hubble is expected to soon return to normal science operations,” said NASA.
So our great telescope is saved. Sadly the news isn’t so good for the other missions – Dawn and Kepler are expected to run out of fuel by the end of the year, and Opportunity still hasn’t spoken to us since shutting down during a global dust storm on Mars.
But for now it’s three cheers for Hubble, and here’s hoping the mission has many more fruitful years ahead of it.