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New Hubble Repair?

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Wade Hampton III

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New Hubble Repair?

PostWed Feb 15, 2017 4:09 pm

Evan Gough posted...

The final servicing mission to the venerable Hubble Space Telescope (HST)
was in 2009. The shuttle Atlantis completed that mission (STS-125,) and
several components were repaired and replaced, including the installation
of improved batteries. The HST is expected to function until 2030 - 2040.
With the retiring of the shuttle program in 2011, it looked like the Hubble
mission was destined to play itself out. But now there's talk of another
servicing mission to the Hubble, to be performed by the Dream Chaser Space

The servicing mission to the Hubble would be a sort of insurance policy
in case there are problems with NASA's new flagship telescope, the James
Webb Space Telescope (JWST.) The JWST is due to be launched in 2018, and
its capabilities greatly exceed those of the Hubble. But the James Webb's
destination is LaGrange Point 2 (L2), a stable point in space about 1.5
million km (932,000 miles) from Earth. It will enter a halo orbit around
L2, which makes a repair mission difficult. Though deployment problems
with the JWST could be corrected by visiting spacecraft, the Telescope
itself is not designed to be repaired like the Hubble is.

Not Pre-Ordained
hubble-Re-entry.jpg (72.3 KiB) Viewed 259 times

Since the JWST is risky, both in terms of its position in space and its
unproven deployment method, some type of insurance policy may be needed
to ensure NASA has a powerful telescope operating in space. But without
Space Shuttles to visit the Hubble and extend its life, a different
vehicle would have to be tasked with any potential future servicing
missions. Enter the Dream Chaser Space System (DCSS). The Dream Chaser
Space System is kind of a smaller Space Shuttle. It can carry seven people
into Low-Earth Orbit (LEO). Like the Shuttles, it then returns to Earth
and lands horizontally on an airstrip. The HST has been called the most
successful science project ever. Entire books have been written detailing
its contributions to science. It would be a sad end for the Hubble if it
was somehow rendered useless because of a simple-to-fix problem, yet stayed
in orbit, just out of reach. Somehow, that doesn't seem right. Even though
it was put into Low-Earth Orbit in 1990, it's still a powerful telescope
that keeps delivering results. A back-up plan to keep Hubble running is smart.
The DCSS is built by Sierra Nevada Corporation. It will be launched on an
Atlas V rocket, and will return to Earth by gliding, where it can land on
any commercial runway. The DCSS has its own reaction control system for
maneuvering in space. Like other commercial space ventures, the development
of the DCSS has been partly funded by NASA.

The James Webb has a complex deployment. It will be launched on an Ariane 5
rocket, where it will be folded up in order to fit. The primary mirror on
the JWST is made up of 18 segments which must unfold in three sections for
the telescope to function. The telescope's sun shield, which keeps the JWST
cool, must also unfold after being deployed. Earlier in the mission, the
Webb's solar array and antennae need to be deployed. This video shows the
deployment of the JWST. It reminds one of a giant insect going through
metamorphosis. If either the mirror, the sunshield, or any of the other
unfolding mechanisms fail, then a costly and problematic mission will have
to be planned to correct the deployment. If some other crucial part of the
telescope fails, then it probably can't be repaired. NASA needs everything
to go well. People have been waiting for the JWST for a long time. It's had
kind of a tortured path to get this far. We all have our fingers crossed that
the mission succeeds. But if there are problems, it may be up to the Hubble
to keep doing what it's always done: provide the kinds of science and stunning
images that excites scientists and the rest of us about the Universe.

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