As engineers prepare NASA's the space shuttle Discovery for a July launch, the orbiter's next astronaut crew is training hard for the upcoming spaceflight.
"It's amazing to see how dedicated everyone is," said Lisa Nowak, a mission specialist for NASA's STS-121 spaceflight, of the teams of workers preparing Discovery for flight. "We know that they've been working very hard and are giving is the safest shuttle and tank that they can."
Shuttle workers at NASA's Kennedy Space Center (KSC) in Florida have attached Discovery to the external fuel tank and solid rocket boosters that will launch it into orbit. The orbiter rolled into NASA's cavernous Vehicle Assembly Building - where shuttle launch stacks are assembled - on May 12 and is due to roll out to the Pad 39B at 2:00 a.m. EDT (0600 GMT) on May 19.
Meanwhile, Nowak and her STS-121 crewmates continue to prepare for a planned July 1 launch toward the International Space Station (ISS) on NASA's second test flight since the 2003 Columbia accident. The astronauts spent last week conducting spacewalk rehearsals and long-duration flight simulations with mission controllers and a stand-in space station crew, NASA officials said.
"It does seem more real, and I can't identify why," Nowak told SPACE.com of the STS-121 launch - which will mark the first spaceflight of her astronaut career - in a recent interview. "Maybe it's just because really everybody is more confident that everything is ready to go. You can feel that all around the [Johnson Space Center] and I'm getting very excited."
Commanded by veteran astronaut Steven Lindsey, NASA's STS-121 mission has weathered a series of delays since the space agency launched its first post-Columbia accident mission - STS-114 aboard Discovery - in July 2005. The STS-121 crew also includes pilot Mark Kelly, mission specialists Michael Fossum, Stephanie Wilson and Piers Sellers, and European astronaut Thomas Reiter. Reiter will join the International Space Station astronauts as the outpost's third crewmember.
The STS-121 crew will deliver a cargo module full of supplies to the ISS, as well as stage at least two spacewalks to test shuttle flight safety and repair improvements and conduct station maintenance. A third spacewalk, which NASA has pulled from the mission plan, could be performed pending available shuttle power resources.
"We're still training for all three spacewalks," STS-121 spacewalker Piers Sellers, who will make his second spaceflight during the mission, told SPACE.com. "I will bet you a small sum of money, because that's all I have, that we will do all three in fact."
During the mission's first spacewalk, Sellers and STS-121 mission specialist Michael Fossum will test the stability of Discovery's orbital boom - a 50-foot (15-meter) extension that about doubles the length of orbiter's robotic arm - by perching themselves at its tip. The second excursion is a repair job of the space station's railcar-like Mobile Transporter, with the final spacewalk slated to test shuttle heat shield repair techniques.
"We're hoping to finish the business of showing that we can repair the shuttle to an extent, or to the best extent we can, and also fix all the things on station that have broken while we haven't been flying shuttles," Sellers said.
Engineers have also made a series of changes to the Discovery's external fuel tank to reduce the shedding of large pieces of foam insulation from the vessel at launch. Foam debris was seen during Discovery's STS-114 mission, and a chunk of foam actually struck the space shuttle Columbia's left wing leading edge during its 2003 launch, and has been blamed for the loss of the orbiter and its crew during reentry.
Nowak said she and her fellow crewmembers have kept tabs on NASA's external tank work, with some traveling to KSC while the tank was attached to its solid rocket boosters.
"We get the news briefings and find out everything as it's going on, but we do more than that," Nowak said, adding that STS-121 astronauts also visited NASA's Michoud Assembly Facility to watch workers apply the foam insulation used to prevent ice from forming on the external tank's exterior when it is fueled with super-chilled liquid hydrogen and oxygen.
Nowak, Sellers and their STS-121 crewmates expect to spend about 13 days in orbit, including a week at the ISS, before returning to Earth during their mission. Despite the mission's extended delay, the STS-121 crew remains confident in a July launch.
"Definitely a bit more real, but you can never tell in this business," Sellers said of the upcoming launch date. "This time it looks like everything is going to get lined up for a July launch."
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