NASA’s Hubble Space Telescope is back in action to explore the near and far universe. Scientific instruments are back fully operational, after recovering from a computer problem that suspended telescope observations for more than a month.
Scientific observations resumed in the afternoon of Saturday July 17. Last weekend’s telescope targets included the unusual galaxies shown in the images below.
“I am delighted to see that Hubble has reconsidered the universe, once again capturing the kind of images that have intrigued and inspired us for decades,” said NASA Administrator Bill Nelson. “This is a time to celebrate the success of a team that is truly dedicated to the mission. Through their efforts, Hubble will continue its 32nd year of discovery, and we will continue to learn from the observatory’s transformative vision. ”
These snapshots, from a program led by Julian Dalcanton at the University of Washington in Seattle, show a galaxy with unusually extended spiral arms and the first high-resolution glimpse of an intriguing pair of colliding galaxies. The Hubble Telescope’s other primary targets included globular star clusters and the Northern Lights on the giant planet Jupiter.
The Hubble payload computer, which controls and coordinates the scientific instruments aboard the observatory, suddenly shut down on June 13. When the main computer did not receive a signal from the payload computer, it automatically put the Hubble science instruments into safe mode. This means that the telescope is no longer doing science while mission specialists analyze the situation.
The Hubble team moved quickly to investigate what had happened to the observatory, which orbits about 547 kilometers above Earth. Working from the mission control center at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as well as remotely due to COVID-19 restrictions, engineers collaborated to uncover the cause of the problem.
To complicate matters further, Hubble was launched in 1990 and has been observing the universe for over 31 years. To repair a telescope built in the 1980s, the team had to draw on the knowledge of staff throughout its long history.
Hubble alumni have returned to support the current team in recovery efforts and have lent decades of experience to the mission. For example, the retired employees who helped build the telescope were familiar with the inputs and pans of the scientific instrument, the control and data processing unit, where the payload computer is located. Other former members of the team have lent a hand in researching the original Hubble documents, recovering documents 30 to 40 years old that should help the team chart the course forward.
On June 13, 2021, the Hubble Space Telescope payload computer unexpectedly shuts down. However, the Hubble team systematically identified the probable cause and how to fix it. Credit: NASA’s Goddard Space Flight Center
“This is one of the perks of a program that has been in operation for over 30 years: an incredible amount of expertise and experience,” said Nzinga Tal, director of Hubble’s Anomaly Systems Response at Goddard. “It has been humbling and inspiring to engage both with the current team and with those who have moved on to other projects. There is so much dedication to their Hubble teammates and the observatory and science that Hubble is known for. ”
The new and old members of the team worked together on a list of potential culprits, seeking to isolate the issue to ensure they had a full stock of the future that the devices still worked on.
At first, the team thought the most likely problem was deterioration of memory modules, but switching to backup modules did not resolve the issue. The team then designed and performed tests, which included powering the Hubble Telescope’s standby payload computer for the first time in space, to determine if two other components might be responsible: or the processing unit center itself. However, starting the backup computer did not work, eliminating these possibilities as well.
The team then set out to determine if other devices were involved, including the Data Science Coordinator / Control Unit and Power Controller, which were designed to provide a constant supply of voltage to computers. . However, it would be more complex to deal with either of these issues, and it would be more dangerous for the telescope in general. Switching to these component backup modules will also require changing many other hardware enclosures.
“The switch required 15 hours of driving a spacecraft from Earth. The main computer had to be shut down, and a safe mode standby computer temporarily took over the spacecraft. Several of the boxes also had to be turned on, ”said Jim Gilletick. , deputy director of the Hubble project at Goddard. They had never been executed in space before, and other devices had to change their interfaces. ”” There was no reason to think that all of this wouldn’t work, but the team’s job is to be nervous and think of anything that could go wrong and how we can make up for that. The team meticulously planned and tested every little step in the field to make sure they got it right. “
The team proceeded carefully and methodically from there. Over the next two weeks, more than 50 people worked on reviewing, updating and verifying the procedures for switching to backup devices, and testing them on Simulation HD and a formal review of the proposed plan.
At the same time, the team analyzed data from their previous tests and their results indicated that the power controller was the likely cause of the problem. On July 15, they made the planned switchover to the Science Instrument backup and control and data processing unit, which contains the uninterruptible power supply control unit.
The victory came around 11:30 p.m. EST on July 15, when the team decided the change was a success. The scientific instruments were then put into service and Hubble resumed collecting scientific data on July 17. Most of the observations lost during the suspension of scientific operations will be rescheduled.
This isn’t the first time Hubble has had to rely on backup hardware. The team made a similar change in 2008, returning Hubble to normal operations after another part of the Science Instrument and Command & Data Handling (SI C&DH) module failed. The last Hubble Telescope maintenance mission in 2009 – a much-needed tuning championed by former US Senator Barbara Mikulsky – then replaced the entire SI C&DH unit, dramatically extending Hubble’s operational lifespan.
Since that service mission, Hubble has made over 600,000 observations, bringing its total lifespan to over 1.5 million. These observations continue to change our understanding of the universe.
“Hubble is in good hands,” said Kenneth Simbach, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, which leads Hubble’s science operations. “I am impressed with the team’s dedication and its common goal over the past month to bring Hubble back into service. Now that Hubble has once again provided unprecedented views of the universe, I expect it to continue to amaze us with many future scientific discoveries. “
Hubble has contributed to some of the most Important discoveries of our universe, including the accelerating expansion of the universe, the evolution of galaxies over time, and early studies of the atmospheres of planets outside our solar system. Her mission has been to spend at least 15 years exploring the farthest and weakest regions of the universe, and she goes far beyond that goal.
“The record volume of science presented by Hubble is astounding,” said Thomas Zurbuchen, associate administrator of NASA’s Science Missions Directorate. “We have a lot to learn from the next chapter in Hubble’s life – on its own, along with the capabilities of other NASA observatories. I couldn’t be more excited about what the Hubble team has achieved over the past few weeks. They have faced the challenges of this process firsthand, ensuring that Hubble’s days of exploration are not over yet. ”