The Hubble Space Telescope is a hero in the astronomical world. And when it led to an erroneous gyro on…
The Hubble Space Telescope is a hero in the astronomical world. And when it led to an erroneous gyro on October 5th, it took a heroic effort from Hubbel’s team to make it work again. Now we have Hubbles first picture after returning to the service.
Hubbles first image after their problems will not be the last, thanks to all its gyros and all dedicated people who handle the space telescope. Hubble has, or had, six gyroscopes. The telescope is designed to work with three gyros, with the other three as backups. This was forward thinking, because the gyroscope all finally failed.
Two had previously failed – one in March 2014 and the other in April 201
8-it leaves with four. But on the night of the 5th the error left with only 3 operational gyros, and no backup. When the gyro failed, Hubble hit himself in safe mode. It ended up doing science and pointed to its solar panels by the sun and waited for instructions.
“This has been an incredible story based on the heroic efforts of the Hubble team”, – Hubble senior researcher Jennifer Wiseman, on NASA Goddard.
The gyroscope failed at the start of a three day weekend, and text messages went out to members of the Hubble team and told what happened. Since 2011, the Hubble Control Center has been automated, so when members of the team gathered there, it was like old times.
A chart of Hubble. The six gyrosna are part of the Space Telescope Pointing Control System, which also includes reaction wheels and directional sensors. All of these components work together for Hubble to work. Image: NASA.
More than a dozen members were gathered in the control room at the Goddard Space Flight Center. They tried to revive the failed gyro but failed. They then activated a back-up gyro but reported high speed rotational speeds of 450 degrees per hour. This with Hubble only turns less than one degree per hour.
Dave Haskins is Hubbles mission manager at Goddard, and according to him, it had never happened before. “This is something we have ever seen before on other gyros – rating this high.” Says Haskins.
This error was the last backup for Hubble. Hubble can work with only one gyro, but its abilities are greatly reduced. This one-gyro mode has previously been designed and tested, but the Hubble team did not want to use it until it was their only last option. The one-gyro mode would work, but it would limit Hubble’s efficiency and how much of the sky telescope could observe at a given time of year. If that were to happen, everyone in astronomical society would know that the end was close to the magnificent Hubble.
Team members wondered what to do now, and for the first time in several years, there were people in the control room that continuously monitor Hubble’s health.
“It shows the team’s versatility.” – Dave Haskins, Hubble Mission Operations Manager.
“The team was pulled to staff around the clock, something we have not done over the years,” Haskins shared. Team members went in to take turns – several of Hubble’s system engineers, others who help to run tests and boxes of Hubble’s ground system and some who used Hubble’s control room but did not have a long time. “It has been years since they have been on the console doing this kind of shift work,” said Haskins. “To me it was seamless. It shows the team’s versatility.”
This is not the first time Hubble has had problems with his pek system. In this image, the astronauts replace one of Hubble’s reaction wheels in March 2002. Image Credit: NASA.
Hubble boss Pat Crouse was taken that weekend and recruited a team of experts to analyze the unusual behavior of the super speed gyro and to see what could be done. That group met for the first time on Tuesday, October 9, and contributed insights into Hubble’s recovery. After weeks of thinking through problems and test solutions, the Crous group and the Hubble team suspected that something could physically prevent gyro. But whatever they were, they would have to solve it from the ground. There would be no more quests to fix Hubble.
“Early, we had no idea if we could solve that problem or not.” Mike Myslinski, Hubble’s Vice Mission Operations Manager.
The team decided that they would try to shift the obstruction, if there were one. They repeatedly switched gyros through different operating modes. They rotated the telescope itself with large amounts. Eventually, the high rotational speeds of the sparkling gyro began to fall, eventually returning to near normal.
The team was encouraged by this result, but they were still careful. If any of the gyros reported extremely high spin speeds, Hubble would go back safely and interfere with any science that it did. The team uploaded new software to Hubble to protect against this happening again. They also add the space telescope through some training exercises to simulate true scientific observations. Hubble worked well and the team made relief.
“Early we had no idea if we could solve the problem or not,” says Hubbles vice mission operator Mike Myslinski about high gyro prices.
Another team was hard at work in the background and prepared for an event like so far, they have been avoided. They prepared for Hubble to work on just one gyro, with another in backup as backup. This situation is avoided this time, but it will happen eventually. “We know we have to go to a gyro one day, and we want to be as prepared as possible for that, “explained Myslinski.” We always said that when we came down to three gyros we would do as much up-front work as possible for one-gyro science. That day has come. “
Hubble passes by now as if nothing had happened. Its first science image since the entire deal is a field of galaxies in the constellation Pegasus. The image contains star-forming galaxies up to 11 billion light years away. No problem for Hubble.
Hubble’s first image after returning to service is from a field of galaxies in the constellation Pegasus Image Credit: NASA, ESA and A. Shapley (UCLA)
“This has been an incredible story based on the heroic efforts of the Hubble team,” told Hubble senior researcher Jennifer Wiseman at NASA Goddard. “Thanks to this work the Hubble Space Telescope is back to full science capabilities that will benefit the astronomical community and the public for many years to come. “
Hubble has for many years drive I have become a family member of research, and to the rest of us. We know that one day’s mission is to end, and it will be. It will be a sad day. But for the moment, Hubble still makes science and capture some of the most amazing pictures of the universe we live in.
Enjoy it while we have it!