NASA's Hubble telescope is facing a mysterious computer problem. Here's how they try to fix it

Two weeks ago, NASA's Hubble Space Telescope began showing some troubling symptoms.

NASA, Smithsonian Institution, Lockheed

Currently, NASA engineers are trying to diagnose and repair a computer malfunction; But that's not an easy thing to do when the problem is with a telescope the size of a bus currently orbiting in space, 547 kilometers above our heads, about 27,000 kilometers per hour.

Two weeks ago, NASA's beloved Hubble Space Telescope, which throughout its 31-year career has provided us with many enchanting images of distant stars and galaxies, Some alarming symptoms begin to appear.

The telescope's computer, one of the core systems that controls and coordinates scientific instruments aboard the spacecraft and transmits scientific and engineering data to Earth, has unexpectedly stopped.

This was immediately picked up by the NASA team because the payload computer and the telescope's main computer are constantly sending each other a "stay alive" signal, known to NASA engineers as a "handshake," to indicate that all is well.

On June 13, the handshake was lost, causing the main computer to automatically put all of the telescope's scientific instruments into safe mode. This means that while the telescope continues to aim at its programmed target to make sure the sun continues to hit the solar panels, all instruments onboard are on hold.

At first glance, the flaw doesn't seem particularly alarming, explains Paul Hertz, director of NASA's Astrophysics Division.

"In general, for all of our space telescopes, anomalies that interfere with normal operations occur once or twice a year, so this has never happened before," Hertz tells ZDNet. "Something isn't behaving as the computer expected, so we pause so the human can get into the circuit, figure out what's wrong, and tell the computer what to do next."

Since the launch of Hubble in 1990, as a space observatory tasked with observing the most distant stars and galaxies seen to date, the telescope has been monitored by a team on Earth, which remotely monitors the system and ensures its health and safety.

Similar to Earth-based IT decisions, the team began turning on and off the computer carrying a load, but soon encountered the same problem.

The engineers then assumed that the problem came from a degraded memory module and ran one of the three available spare modules. Once again, the problem persisted and the command to start the backup drive failed. That's when NASA decided to speed things up and turn on the backup payload computer.

The astronauts installed both the payload computer in use so far and the backup system during Hubble's last service mission in 2009. In other words, the NASA team opted for the backup system that had been out of service for 12 years. To set the record straight, this is like trying to bring the Blackberry Storm back to life.

But space does not deal with these terrestrial time frames. "Hubble is 31 years old, so many of the telescope's systems are also 31 years old," says Hertz. "Computers are actually the latest in Hubble since they were installed on the last maintenance mission."

It remains that switching computers was a delicate process, says Hertz, which required carefully crafted procedures and multiple levels of review before getting the green light.

If the backup computer has accumulated so much space dust over the years it has ended up being the least of NASA's concerns. Once the change was successfully implemented, the computer experienced symptoms as before: the commands to write or read from memory did not yet exist.

This means that the case is elsewhere in the telescope. NASA began the search, Hertz says, with a list of ingredients that could be to blame. They even brought back to the team some of the engineers who had worked on Hubble's design for more than three decades.

"It's a lot like detective work," Hertz says. "You have a limited number of clues and you review all your hypotheses to see which ones match the clues. Then, once you have a match, you have to figure out what questions to ask the system, what changes you can make to see how it can help differentiate the hypotheses, and of course, without compromising the observatory.

Among the potential contenders, NASA engineers are particularly suspicious of the Hubble Command Module, which sends commands and data to scientific instruments. The Scientific Data Coordinator coordinates the instruments' scientific data and transmits it to Earth.

But the problem can also come from the power regulator, which supplies voltages to various devices.

It looks like the next few days, and possibly weeks will be about trial and error for NASA engineers, with the added challenge, of course, of having to perform operations on a system that can't be physically touched.

"If Hubble were sitting in a lab, we'd just go, check this component and this component, and immediately find what's wrong," Hertz says. "But we can only talk to Hubble through their radio, we can only ask them to do the things they're scheduled for, and we can only ask them to send the data they're scheduled to send."

Hubble is never programmed to send information on whether the voltage is well distributed across all systems. Therefore, the test will take longer and will require a dose of creativity.

Some might speculate, poetically, that the problem lies entirely elsewhere. In the coming months, Hubble will be joined in space by a new observatory, the James Webb Space Telescope, scheduled to launch in October 2021 to study the evolution of our solar system. Did the telescope feel that, after 31 years, it was time to gracefully retire to make way for the next generation of space observatories?

Of course not, according to Hertz. Today, Hubble can boast a total of 1,400 million observations contributed to 18,000 peer-reviewed scientific articles. The telescope has traveled more than six billion kilometers and transmits about 150 gigabytes of raw scientific data each week.

Therefore, for Hertz, it remains one of the most productive astronomical telescopes in the world and is nowhere set for early retirement.

"We will continue to run Hubble as long as it remains a scientific product," says Hertz. "There's a very long list of problems we can fix, and I'm very sure there's something wrong somewhere on that list. We'll sort it out, make the necessary corrections, and put Hubble back into service."

Working alongside James Webb, Hubble is expected to continue contributing to the scientific community. Assuming NASA can find and fix the current problem, hopefully, it will be some time before the old telescope decides it's time to move.

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