The Hubble Space Telescope has lost the majority of its gyroscopes

The venerable Hubble Space Telescope's gyroscopes have been exhausted, and when there are none left, the instrument will stop doing meaningful science.

In order to maintain the telescope, which has been operating in space for nearly three and a half decades, NASA announced on Tuesday that it will reduce Hubble's operations so that it operates on only one gyroscope. This will limit some scientific operations, and it will take longer to point the telescope at and lock onto new objects.

But in a conference call with space reporters, Hubble officials confirmed that the beloved science instrument isn't going anywhere anytime soon.

“I personally don't see this as a major constraint on their ability to do science,” said Mark Clampin, director of the Astrophysics Division at NASA Headquarters in Washington, D.C.

From six to one

The Hubble Telescope was launched aboard NASA's space shuttle in 1990, and since then, the space agency has flown five maintenance missions to repair and upgrade the complex instrument. To this day, it provides humanity with the best view of the universe in the visible light range of the spectrum.

The last of these service missions was flown by a space shuttle Atlantis In 2009, he made several improvements, including replacing all six gyroscopes that help point and aim the telescope. However, in the 15 years since then, three of the six gyros have failed. In the past six months, another device, the Giro 3, has returned increasingly false data. This caused Hubble to slip into safe mode several times, halting science operations.

As a result, the space agency has only two fully operational gyros. One of these, Gyro 4, operated for a total of 142,000 hours. Another, the Gyro 6, has accumulated 90,000 hours. NASA's plan now is to operate the telescope on a single gyroscope, keeping the second as a “backup” option.

NASA said work on a single gyroscope is possible, with relatively modest implications for observation capabilities. It will be less efficient and require more time to signal. This will result in a loss of about 12 percent of monitoring time. The telescope will also not be able to observe objects closer to Mars, including Venus and the Moon.

However, by taking this step now, the space agency believes it can extend Hubble's operational life by another decade. Patrick Cross, the telescope's project manager, said there is a 70% chance that Hubble can maintain science operations using a single gyroscope until 2035.

“We don't see Hubble as being on its last legs,” he said Tuesday.

From a scientific point of view, it is important that Hubble continues to operate. Now that the powerful James Webb Space Telescope is up and running, the two instruments make a great duo. By observing Hubble in visible light and Webb in infrared, astronomers can extract valuable new insights into the nature of the universe.

Another service task? No thank you

In addition to aging scientific instruments and a declining number of gyroscopes, NASA also faces some other challenges regarding instrument life. The telescope typically operates between 615 km and 530 km above the Earth's surface. However, the telescope will likely drop below 500 kilometers sometime this year. At low altitudes, some telescope observations are affected by other satellites in low Earth orbit.

Clampin said Tuesday that telescope operators do not expect Hubble to return to Earth's atmosphere before the mid-2030s. This, combined with the gyroscope limit, appears to place firm limits on the maximum remaining lifetime of Hubble.

However, in 2022, Jared Isaacman, the billionaire who flew on the plane The first fully commercial human mission To orbit aboard the Crew Dragon, I approached NASA about performing a servicing mission for the Hubble Space Telescope. He proposed funding most of the mission that would have, at a minimum, re-enhanced the Hubble Space Telescope by at least 50 kilometers.

After NASA and SpaceX conducted a feasibility study late that year, the space agency was recommended to further investigate the possibility of a commercial mission. At a minimum, the telescope could be safely re-boosted, but there were also options that included attaching star trackers and external gyroscopes to compensate for the telescope's malfunctioning guidance system.

But NASA decided not to pursue this option.

“Our position now is that after exploring existing commercial capabilities, we will not proceed with the reconsolidation process now,” Clampin said on Tuesday.

Asked about the study, which NASA declined to publish for proprietary reasons, Clampin said: “It was a feasibility study to help us understand some of the issues and challenges we might have to face.” “There were options like the possibility of making improvements by adding gyroscopes to the outside of the telescope, but they were really just theoretical concepts.”

Apparently NASA decided it was safer to let Hubble age on its own, rather than risk private hands touching the sacred telescope. We're about to see how it goes.