Hubble Space Telescope sidelined by serious pointing failure

Creally do,” said Kenneth Sembach, director of the Space Telescope Science Institute, which operates Hubble. “The fact that we’re having some gyro problems, that’s kind of a long tradition with the observatory.”

Gyroscopes are needed to keep the 340-mile-high (540-kilometer-high) Hubble pointed in the right direction during observations. Precise pointing is crucial: Astronomers use the telescope to peer deep into the cosmos, revealing faraway solar systems as well as galaxies and black holes. Just last week, astronomers said they may have discovered the first moon outside our solar system, with Hubble’s help.

Since its launch in 1990, Hubble has made more than 1.3 million observations.

Two of Hubble’s gyroscopes are working fine, Sembach said. The last one was in reserve; it was turned off some years ago after exhibiting some “funny behavior” even though it was getting the job done, he said. That’s the one that flight controllers turned on Saturday as a backup; as of Monday, it still wasn’t working as expected.

Sembach said everyone wants to be careful in attempting a repair.

“Obviously, we don’t want to make things worse,” he said.

Hubble normally uses three gyroscopes to function, but could get by with one or two, something it’s done before. But that leaves little room for additional breakdowns. Besides redundancy, three functional gyroscopes also provide more flexibility in pointing, Sembach said.

“We’ll be fine,” he said from the Baltimore institute. “I’m sure Hubble has many years of good science ahead of it.”