Two
astronauts are preparing to take at least two strolls in space outside NASA's
Discovery shuttle after it launches into orbit Saturday.
STS-121
spacewalkers Piers
Sellers and Michael
Fossum are charged with some vital tasks during
their 12-day spaceflight, not the least of which is making pivotal
repairs that will make or break the future of the International Space
Station (ISS).
A mix of
experience and enthusiasm, Discovery's spacewalking team will test heat shield
repair methods and fix a vital cable reel on the space station's Mobile Base
Transporter - a railcar that is vital for ISS construction.
"It's been
about two years of pretty hard work," Sellers said of his mission training in a
prelaunch interview.
Discovery's
STS-121 mission is slated to launch at just past 3:48 p.m. EDT (1948 GMT) on July 1 on NASA's
second shuttle flight since the 2003 Columbia tragedy. STS-121
pilot Mark Kelly will assist Sellers and Fossum from
inside Discovery, NASA officials said. The pair could make an additional
spacewalk if orbiter resources allow.
Funnyman
takes the lead
A veteran
of one shuttle flight and three spacewalks, Sellers is by far considered the funnyman
of the STS-121 mission by his crewmates and will lead the spaceflight's
multiple spacewalks.
"We all
make fun of each other," said Sellers, 51, adding that humor can break tension
during training. "You have to think of training as a marathon, it goes on for
many months, and then you get a slip and sometimes if can feel like it's
getting frustrating. And then you feel like laughing."
A native of
Crowborough, Sussex in the United Kingdom, Sellers joined NASA's astronaut
corps in 1996 and flew aboard the Atlantis shuttle during its ISS-bound STS-112
mission in 2002.
"It's great
just to sit there and think about where you are," Sellers said of shuttle
flights. "And think, this is a remarkable place to be
with the world spinning through space below you, and you in this little ship
floating around it."
Sellers, who is married and has two grown children, will ride at the end of Discovery's
50-foot (15-meter) orbital boom during the first STS-121 spacewalk to check its
stability as a work platform for heat shield repair. He and Fossum
will then repair the Mobile Base Transporter's cable reel system.
"As long as
[it] can move up and down, we can build the space station. Right now it's
broken and we're going to try to fix it," Sellers said of the complicated task.
"It's not a sure thing by any means."
A third
spacewalk, to check a series of heat shield repair techniques, will likely be
added later in the mission, the experienced spacewalker said.
"I would be
very surprised if we didn't do it," Sellers said, adding that Discovery's
cryogenic fuels should be ample enough to support the third spacewalk unless
the orbiter is stuck on the launch pad for several days for some reason. "That
would require some bad luck."
First-time
spacewalker
Aiding
Sellers in the STS-121 spacewalk is Michael Fossum,
48, who will make his spaceflight debut with Discovery's planned July 1 launch.
"I love the
space business," said Fossum, who grew up in McAllen, Texas, in a preflight interview. "I
wanted to be part of it one way or another."
A former
U.S. Air Force test pilot and colonel in the USAF Reserves, Fossum
joined NASA in 1993 - five years before he became an astronaut - to test the
potential of Russian Soyuz spacecraft for use on the ISS. He helped in an ISS
redesign and later served as a flight test engineer on NASA's X-38 space
station crew escape vehicle.
Fossum,
who is raising four children with his wife Melanie, considers his spaceflight
another notch in his family history, which has been packed with explorers since
his first ancestors came to the U.S. from Norway, Ireland and Germany more than 130 years ago.
"It's
really a large part of what makes me who I am," Fossum
said. "The romantic in me likes to think that I'm living just a little fraction
of that life."
Outside
NASA, Fossum holds scouting high on his list of
activities and is himself an Eagle Scout from his days with the Boy Scouts of
America.
"I know
that it has changed my life in many significant ways and...I like the opportunity
now to help work with the kids," Fossum said in a
NASA interview, adding that his troop has given him some gruff about missing
this summer's major camping trip. "The guys give me a hard time, telling me I'm
going to be missing next summer's High Adventure activity because I'm working
on another one for NASA."
Despite the
busy schedule facing the STS-121 astronaut, Fossum
hopes for a free moment to absorb the feat he and his crewmates are
accomplishing.
"I hope to
have a few minutes just to appreciate the opportunity that I've got," Fossum said. "To have it sink in without having to rush to
the next task."
Robert Z.
Pearlman contributed to this story.
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