HOUSTON - After seven years circling
the Earth all alone, the ailing Hubble Space Telescope is about to meet some
old friends.
NASA's space shuttle Atlantis and
seven astronauts raced
toward Hubble on Wednesday for a planned midday rendezvous to begin a risky
and complicated overhaul of the 19-year-old space telescope. Three of the
Atlantis astronauts are returning to Hubble, including the shuttle's skipper Scott
Altman, who led NASA's most recent service
call on the observatory in 2002.
"I'm hoping it's as shiny as when we
last left it," Altman told SPACE.com before
launch. "I'm looking forward to seeing it out there."
Space junk crossing
Hubble's orbital neighborhood 350
miles (563-km) above Earth isn't the safest of places. There's so much space
junk in the region that it is one of the top
risks to Atlantis and its crew. The shuttle has a 1-in-229 chance of
suffering a critical blow. That's a higher debris risk than on typical shuttle
flights, but just within NASA's flight rule limits, agency officials have said.
NASA plans to fly Atlantis in
special attitudes to reduce the chance of severe strikes from debris and
micrometeorites, and the shuttle will retreat to a safer orbit as soon as it
leaves Hubble next week. There's even another shuttle - Endeavour - primed to
launch a rescue
mission if Atlantis is hit so badly it cannot return its astronauts home.
Hubble, though, has had no relief
from space debris and the harsh space environment. The astronauts and Hubble
scientists have steeled themselves for pockmarks, loose insulation blankets and
other wear and tear that may have stacked up over the years.
"It could be tattered a little bit,"
Altman said.
Altman and his crew will inspect
Hubble after arriving to take stock of the space telescope's health. On Earth,
a team of NASA engineers are doing the same for Atlantis to make sure the
shuttle's heat shield has not been critically damaged by launch debris. The astronauts
discovered some small dings in the heat shield Tuesday, but mission managers
said the actual damage was quite minor.
Within arm's reach
Atlantis is due to arrive at Hubble
at about 12:54 p.m. EDT (1654 GMT) as the shuttle pulls up below the telescope
so astronaut Megan McArthur can reach out with a robotic arm and grab it. She
will park the 13-ton Hubble, which is the size of a school bus, atop a
turntable-like platform in the shuttle's cargo bay that gives easy access to the telescope's innards and
exterior.
The astronauts plan to perform five
ambitious spacewalks in as many days to replace basic items like batteries
and gyroscopes, install two new cameras and attempt tricky repairs to two
instruments that were never designed to be fixed in space.
There's no guarantee those fixes
will work, even if the spacewalks go well, NASA has said. But if everything
goes according to plan, Hubble will be more powerful than ever and live on
through at least 2014, mission managers said.
"I personally think the stakes for
science are very high," said David Leckrone, Hubble's senior project scientist
at NASA's Goddard Space Flight Center. "There's simply no two ways about it."
Altman and Atlantis spacewalkers
John Grunsfeld and Michael Massimino are all returning to Hubble. Grunsfeld -
an astrophysicist and astronaut - is making his third trek to the observatory.
"I really feel like Hubble is kind
of a friend, and I'm going to visit an old friend that I haven't seen in a long
time," Grunsfeld said before flight. "And it's going to be a little bit more
weathered."
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