NASA's final
shuttle mission to overhaul the Hubble Space Telescope has a firm September
2008 launch date, the space agency announced Thursday.
A
seven-astronaut crew and the shuttle Atlantis, which currently stands poised
for a Friday launch to the International Space Station (ISS), will rocket
towards Hubble on Sept. 10, 2008 to give the orbital telescope its fifth and
final makeover.
Squeezed in
between NASA's remaining shuttle flights to complete space station
construction, the STS-125 mission to Hubble will extend the orbital observatory's
lifetime through 2013. Without the vital servicing mission, Hubble's major science
activities would likely end around 2009, with only basic functions remaining
through 2011, Hubble managers have said.
"This
is the one mission not going to the space station, so it has to be accommodated
on the fitness of Hubble," NASA spokesperson Allard Beutel told SPACE.com
of the September 2008 launch date. "This gives us the time to be able to do that while at the same time fitting it into the space station construction
schedule."
NASA plans
to complete assembly of the ISS by September 2010, when its aging three-orbiter
shuttle fleet is due to retire. The space agency initially
canceled the final $900 million Hubble servicing mission in 2004, finding
the flight too risky after the 2003 Columbia accident.
But wide
disapproval of that decision, coupled with support from NASA chief Michael
Griffin, led NASA to first study a robotic mission to Hubble before finally returning
to the astronaut-based
servicing flight aboard Atlantis last October.
As a safety
measure, the space shuttle Endeavour is expected to serve as a possible rescue
ship should Atlantis suffer critical heat shield damage during launch, Beutel
said. Unlike ISS construction flights, in which shuttle astronauts can stay
aboard the space station if their orbiter is damaged, the STS-125 crew will not
have that safe haven option, NASA officials added.
Commanded
by veteran shuttle flyer Scott Altman, the planned 11-day Hubble flight --
known as Servicing Mission-4 -- will feature five spacewalks to refit the
orbital telescope.
The STS-125
crew is expected to: repair one of Hubble's spectrographs and install another;
boost the space telescope's orbit; overhaul its attitude control system,
replace batteries, thermal insulation and a broken guidance sensor; and install
the Wide Field Camera-3 to enhance the observatory's vision.
Hubble researchers
have said that they hope the addition of Wide Field Camera-3 will make up for
the loss of the observatory's primary camera -- the Advanced Camera for Surveys
-- which went
offline earlier this year.
The September
2008 servicing mission will be the fifth shuttle flight to overhaul Hubble
since the space observatory's April 1990 launch aboard the Discovery orbiter.
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