This story was updated May 22 at 4:53
a.m. EDT.
CAPE CANAVERAL, Fla. - Atlantis
astronauts are hoping for a break in the weather for their planned Friday
landing as they prepare to wrap up their successful mission to tune up the
Hubble Space Telescope.
Atlantis is slated to touch down on
the runway here at NASA's Kennedy Space Center (KSC) Friday just after 10:00
a.m. EDT (1400 GMT), but only if the weather allows. The forecast is grim, with
the potential for rain showers and thunderstorms near the landing strip may
keep the shuttle in orbit longer
than planned, NASA officials said.
"The weather for KSC on Friday, I'll
tell ya, doesn't look great," said entry flight
director Norm Knight. "We expect it's going to improve over the next couple of
days, but again we'll just have to wait and see."
Atlantis has two chances to land
Friday, with the second arising at 11:39 a.m. EDT (1539 GMT). But the shuttle could
also try again Saturday and choose either its Florida runway or a backup
landing strip at Edwards Air Force Base in Southern California. The shuttle has
enough supplies to remain in space until Monday, Knight said.
Atlantis commander Scott Altman and
his seven-astronaut crew are finishing up an 11-day
mission to the 19-year-old Hubble, where they plowed through five
exhausting spacewalks in as many days to leave the iconic observatory more
powerful than ever. It was NASA's fifth, and last, mission to Hubble before
retiring its three-shuttle fleet next year.
Returning to Earth with Altman are shuttle pilot Gregory H. Johnson and mission specialists
Michael Good, Megan McArthur, John Grunsfeld, Michael Massmino
and Andrew Feustel.
The weather for the crew's landing
is dynamic. Mission Control radioed the astronauts to say that there's a chance
the sky may clear in time for at least one landing attempt, but they'll know more
later today.
"There are
a lot of issues against us, however it's a very dynamic situation and we're
going to keep an eye on it closely," Mission Control said.
NASA prefers to land space shuttles at the Kennedy Space Center here because it
is the home port and launch site for the fleet. It also saves about a week of
time and $1.8 million by avoiding the need to ferry a shuttle from its backup
runway in California to Florida using NASA's modified 747 jumbo jet transport
craft.
Hubble's new lease
Despite a series of unexpected
hitches - like stuck bolts, handrails and balky gyroscopes - that slowed their
work, the astronauts labored tirelessly through to repair Hubble. Their efforts
should extend the space telescope's cosmic scans of the sky through at least
2014 or longer.
The Atlantis
astronauts installed two new instruments in Hubble and fixed two
long-broken ones that were never designed to be fixed in space. They also
replaced several vital components, like batteries and gyroscopes, to upgrade
Hubble's systems.
Grunsfeld, the mission's
spacewalking chief and a self-described "Hubble hugger," said he
expected to be sad when Atlantis left Hubble in space Tuesday, but felt pride
instead.
"Everything worked, we deployed
Hubble and it's at the apex of its capabilities," said Grunsfeld, a
five-time spaceflyer who made his third trip to
Hubble. "We pulled it all off. It was a very hard mission."
The new instruments are expected to
push Hubble's vision deeper
into space and peer back to a time when the universe was just 500 million
years old. The universe is currently 13.7 billion years old. Hubble scientists
will start calibrating the telescope's instruments next week and plan to resume
science observations by the end of summer.
Atlantis' final flight to Hubble
cost about $1.1 billion, about one-tenth the total $10 billion invested in the
beloved observatory.
Triumph at Hubble
Lead flight director Tony Ceccacci said that there were some people who had little
faith in the spaceflight, which was once deemed so risky that it was canceled.
NASA called the service call off five years ago after the Columbia disaster and
studied a potential robotic service call before reinstating the manned mission
in 2006.
To deal with the added risk of space
debris damage and Hubble's already high 350-mile (563-km) orbit, which put
Atlantis out of range of the lower International Space Station and its
different 220-mile (354-km) orbit, NASA made an unprecedented decision.
It kept the shuttle Endeavour and a
crew of four astronauts on standby, ready to launch a rescue mission within a
week of an emergency. No rescue was needed and Endeavour stood down from rescue
status on Thursday.
"There were folks who thought
we couldn't do this," Ceccacci said before
landing. "They always told us 'you're too aggressive, you're going to get
in trouble.'"
But the more than two years of
training, planning and preparation paid off for the Atlantis astronauts and
their flight control team on Earth. Not only did the tireless
astronauts overhaul Hubble, but they pushed through all of Hubble's
unexpected obstacles to hit all their mission goals.
"I don't want to tell you I
told you so, but I told you so," Ceccacci said
with a smile.
It wasn't always easy going. The
astronauts spent more than 36 hours working on Hubble, at times tackling
intricate repairs that had no guarantee of success. Then flight controllers
powered the long-dead instruments back up to the delight of the astronauts and
scientists on Earth.
The Atlantis crew also gave Hubble
one extra addition: a docking ring to allow a future robotic spacecraft to
latch on and send it plunging into the Pacific Ocean when its mission is over
sometime after 2020.
Mission Control roused the
astronauts early Friday with "The Galaxy Song," a tune from the film "Monty
Python's The Meaning of Life."
"Atlantis, we hope that soon you'll
remember what it's like to stand on the planet,"
Mission Control radioed the crew.
"And Houston, thanks for that,"
Altman replied. "We're looking forward to that as well."
SPACE.com is providing continuous
coverage of NASA's last mission to the Hubble Space Telescope with senior
editor Tariq Malik at the Kennedy Space Center and reporter Clara Moskowitz in
New York. Click here for
mission updates and SPACE.com's live NASA TV video feed. Live
landing coverage begins at about 6:30 a.m. ET.
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