NASA is working to save its prized space telescope, Hubble, after a
mysterious computer issue took it offline last week.
Hubble launched into space in 1990 and immediately began capturing the
universe in revolutionary detail. The Earth-orbiting observatory has imaged
the births and deaths of stars, discovered new moons around Pluto, and
tracked two interstellar objects as they zipped through our solar system. It
has allowed astronomers to calculate the age and expansion of the universe.
It has spotted galaxies more than 13.4 billion light-years away, thereby
capturing light from the universe's early years.
But the telescope's payload computer suddenly stopped working on June 13. That
computer, built in the 1980s, is like Hubble's brain - it controls and
monitors all the science instruments on the spacecraft. So NASA engineers
rushed to analyze data from the telescope to pinpoint the problem.
They still haven't figured out why the computer halted. NASA tried, and
failed, to restart it on June 14. Initial data indicated that the issue could
stem from a computer-memory module that was degrading, so the Hubble team
tried switching to one of three backup modules onboard the telescope. But the
command to start up the new module didn't work. On Thursday, the Hubble team
tried again to bring both the current module and the backup online. Both
attempts failed.
So now the Hubble operations team "will be running tests and collecting more
information on the system to further isolate the problem," NASA said in an
update on Friday.
In the meantime, Hubble's science instruments are in a hibernation-like
"safe mode." They're all in good health, NASA said on Friday, as is the
telescope itself.
Hubble has a second payload computer that it should be able to switch to if
NASA can't restore the current one.
Hubble has seen many fixes and upgrades in its 30 years
This isn't the first time Hubble has glitched or needed an upgrade - not
even the first time this year. In March, a software error sent the
observatory into safe mode. But within a week, NASA had fixed the problem
and gotten the telescope back online.
Hubble is the first telescope designed for in-orbit servicing. Astronauts
have visited the observatory to fix problems or replace old parts on five
occasions.
The last such Hubble-servicing mission, in 2009, repaired two failing
instruments and gave the telescope a new computer, new batteries, new
insulation, a new camera, and a spectrograph.
By replacing or upgrading aging parts in this way, astronauts have given
Hubble new capabilities throughout its life. That's why the telescope is still
conducting groundbreaking science 30 years after its launch. It's unlikely,
however, that NASA would send astronauts to address the current problem
because the backup computer should be able to fix it.
NASA also plans to launch a more sophisticated space telescope into orbit in
November. The new observatory, called the James Webb Space Telescope, will
have a field of view about 15 times larger than Hubble's.
Even though JWST is not intended to be a Hubble replacement, the legacy
space telescope can't go on forever. During the 2009 mission, astronauts
also installed a device that can push Hubble into Earth's atmosphere when it
comes time to decommission the telescope. As it falls towards Earth,
friction will heat the observatory until it burns up. It's unclear when that
might be necessary.