WASHINGTON, June 4, 2024 (BSS/AFP) - The venerable Hubble Space Telescope,
which has revolutionized astronomical discovery since its launch in 1990,
will ease into retirement with a scaled-back observing schedule, NASA
officials said Tuesday.

One of the three gyroscopes that control the direction in which the telescope
points has become unstable in recent months, leading to intermittent "safe
mode" episodes -- most recently on May 24.

"After completing a series of tests and carefully considering our options, we
have made the decision that we will transition Hubble to operate using only
one of its three remaining gyros," said NASA's Mark Clampin, director of the
astrophysics division.

The other gyro will be kept powered up in reserve for potential future use.

The transition, which should be completed by mid-June, will reduce Hubble's
efficiency at carrying out science observations by 12 percent, dropping from
85 orbits a week to 74, said Patrick Crouse, project manager for the Hubble
Space Telescope mission.

Over the course of a year, it will still be able to view the full night sky.
It will no longer be able to track objects that are closer than Mars --
though such targets were rare anyway, added Crouse.

NASA calculates there is a greater than 70 percent chance of operating with
this configuration through 2035. At the end of the telescope's life, the US
space agency plans to safely de-orbit or otherwise dispose of the popular
science instrument.

"We do not see Hubble as being on its last legs, we do think it's a very
capable observatory, (poised) to do exciting science with other observatories
in orbit and those that will join us in orbit," said Crouse.

- Most distant star -

Named for astronomer Edwin Hubble, the telescope was launched in 1990 and
operates about 320 miles (515 kilometers) above Earth.

Between 1993 and 2009 astronauts visited Hubble five times on repair
missions.

NASA and SpaceX previously said they were studying a possible mission that
would re-boost Hubble's orbit, which gradually decays over time due to
Earth's gravitational pull, and part of that review also considered ways to
mitigate against the loss of gyros.

But Clampin said ideas of adding extra gyros to the outside of the telescope
were "just notional concepts -- we never even got to the point of actually
looking at what that would look like, and how we would do that."

Arguably among the most valuable instruments in scientific history, Hubble
continues to make important discoveries, including in 2022 when it detected
the farthest individual star ever seen -- Earendel, whose light took 12.9
billion years to reach us.

Clampin said despite its diminished capacity, Hubble keeps performing a
"breadth of great science," from investigating objects in our solar system to
studying early galaxies to collaborating with the newer James Webb Space
Telescope to probe the atmospheres of exoplanets.

While Webb, now the premier space telescope, excels in infrared detection,
Hubble's primary focus on visible light provides a complementary capability,
enhancing their combined scientific impact.