[From NASA HQ website,
http://www.nasa.gov/vision/universe/.../hst2004.html]

April 29, 2004

NASA Is Not Giving Up On Hubble!

Looking for Creative Ways to Extend Observatory's Life

Susan Hendrix, NASA Goddard Space Flight Center

How do you extend the life of an orbiting space telescope without sending
astronauts to fix it? This is the very question that NASA's most creative
engineers are pondering these days.

The tragic loss of the Shuttle Columbia last year, and the recommendations of
the Columbia Accident Investigation Board (CAIB), led NASA Administrator O'Keefe
to give the Hubble Space Telescope team an enormous challenge -- determine
whether a robotic mission is possible and how it could potentially extend the
useful life of Hubble. The outcome of this challenge could also provide new
capabilities in human-robotic exploration for the Vision for Space Exploration
[http://www.nasa.gov/missions/solarsy...ore_main.html].

No further Shuttle servicing of Hubble

Among its recommendations, the CAIB called for various improvements to the
Shuttle fleet before it can return to flight, as well as other measures that
need to be adopted over the long term.

One lesson NASA learned from Columbia is that astronauts need a place to take
shelter if their Shuttle is damaged. On a Hubble mission, unlike a mission to
the International Space Station (ISS), there would be no such refuge for astronauts.

To rescue a Shuttle crew performing a Hubble servicing mission, NASA would need
to have a second Shuttle positioned for launch, requiring an unprecedented
double workload for ground crews. Then there's the issue of the rescue itself.
To do this would involve a Shuttle-to-Shuttle crew transfer, which is something
NASA has never before attempted. All this would have to be done under extreme
schedule pressure because the Shuttle's life support, food and water resources
are extremely limited.

A mission to the ISS, however, would allow astronauts from a damaged orbiter to
take safe shelter, giving NASA more time, more options and greater capabilities
to mount a rescue.

What about a robotic servicing mission?

How can Hubble safely be de-orbited without a Shuttle mission? And is it
possible for a robot to actually upgrade Hubble? The answers may lie in recent
advancements in robotics technology. Engineers from around NASA, led by a team
at the NASA Goddard Space Flight Center, are currently looking into several
promising scenarios.

First and foremost, engineers are working on a plan to safely dispose of Hubble
once it concludes its scientific mission. Satellites in low Earth orbit
eventually fall back to Earth, and Hubble will share that fate perhaps as soon
as 2013 if nothing is done to boost its orbit and keep it in space. The biggest
problem -- Hubble is the size of a large school bus and it has no propulsion
system that could be used to guide it down safely into the ocean once its
scientific mission is over. NASA can't just let it fall to Earth unguided since
it passes over many populated areas, so engineers need to design a robotic
propulsion system that could be launched on an expendable rocket and attached to
the bottom of the telescope. Ground controllers could then control the re-entry
and direct Hubble to a safe splash-down far from any populated areas.

This same team of engineers is also considering ways to effectively replace or
repair the observatory's aging hardware and perhaps even its scientific
instruments. The most important are the batteries, which should last until maybe
late 2007 or early 2008. Engineers think it may be possible to send a robot that
could attach itself to Hubble and plug a new set of batteries into the
telescope. How could robots do that? Keep in mind that Hubble was designed so
that astronauts could do things like change equipment, computers, and other
components, so if a robot could be designed that could turn the same bolts and
open latches and other tasks, maybe it could be done.

Other things like gyroscopes -- which point Hubble at stars and far-away
galaxies very precisely -- and instruments would present some pretty big
challenges for any robot to replace on Hubble. Perhaps it's possible, but no one
said it will be easy!

The good news is that a lot of amazing new robotic technologies have come along
in the past few years, and some show promise that they might be able to do at
least some of the things we would like to do on Hubble.

NASA Getting Extra Help

As NASA considers ideas for safely extending and completing Hubble's mission,
experts in the nation's scientific and engineering community are also being
asked to help. NASA formally requested a study by the National Research Council
to ensure all reasonable alternatives for extending the lifetime of this
national asset have been fully considered.

Meanwhile, the observatory continues to provide us with unparalleled views of
the universe, complementing the capabilities of the Chandra and Spitzer
telescopes also on orbit. Together with the upcoming Kepler and James Webb Space
Telescopes, as well as an array of astronomical observatories on the ground, we
will continue to increase dramatically our knowledge of the universe in which we
live. So stay tuned!

For more information about Hubble, space science, or human spaceflight, visit:
Hubble Space Telescope Site, http://hubble.nasa.gov .