CAPE CANAVERAL, Fla. -- With its cracked plumbing repaired and a much-anticipated television camera mounted to its exterior, shuttle Atlantis is ready to blast off this week on a complex 11-day assembly mission to the International Space Station (ISS).
Liftoff of NASA's first shuttle mission in nearly four months is expected between 2 and 6 p.m. EDT (1800 and 2200 GMT) Wednesday. The space agency won't release the exact launch time until Tuesday afternoon because of security concerns.
Although officials would not offer any details that might give away the launch time or compromise the security of the flight crew, sources told SPACE.com on Sunday that everything was still looking good for a launch on Wednesday.
Technically the shuttle is behaving itself and none of the severe weather associated with tropical storms in the Caribbean or the Atlantic Ocean appears to be a threat for NASA's 111th shuttle voyage to begin.
The five astronauts and one cosmonaut who will make the journey to the orbiting laboratory were scheduled to arrive at the Kennedy Space Center this weekend. A standard three-day final countdown to launch also was set to begin.
The crew includes mission commander Jeff Ashby, pilot Pam Melroy, mission specialist Sandy Magnus, cosmonaut Fyodor Yurchikhin and spacewalkers Dave Wolf and Piers Sellers. Magnus, Sellers and Yurchikhin are the rookies on this flight, while Wolf is the most experienced crewmember having served aboard the Russian space station Mir for 119 days during 1997-98."This crew has really come together," Ashby said during a pre-flight interview. "We understand each other. We know each other's strengths and weaknesses. Everyone works very hard, and I'm really excited to be going to space to do this mission with them."
Keeping cool
The main goal of this fourth flight of the year is to attach a $390 million truss segment to one already bolted to the ISS. Known as S-One (S1), the 45-foot-long (13.7-meter) truss holds three radiators and much of the plumbing that will be required to keep the entire complex cool once additional modules and power-generating solar arrays are added in the future.
Three spacewalks will be required to make all the electrical, mechanical and other connections between the new S1 truss and the S-Zero (S0) truss, which was bolted atop the Destiny science module during Atlantis' last mission to the outpost in April. The two segments are among 11 planned for the station and that will eventually stretch the length of a football field.
Along the way there will be time for a few science experiments, the transfer of several hundred pounds of supplies and the installation of a new treadmill for the space station's current Expedition Five crew of Valery Korzun, Sergei Treschev and Peggy Whitson.
"This is going to be another challenging assembly mission for us, but a lot of folks on the ground have put forth a lot of effort getting the station hardware ready to fly and making sure the shuttle orbiter is ready to go," said station flight director Andrew Algate.
Long summer
Preparing Atlantis for launch took a little longer than planned, thanks to a sharp-eyed inspector who on June 17 found tiny cracks within the plumbing of Atlantis' propulsion system.
The cracks were in metal flow liners inside the main liquid hydrogen fuel lines that feed the shuttle's three Rocketdyne main engines. So while there were no cracks in the actual fuel pipes themselves, the concern was that metal pieces from the flow liners might break off and fly into the engines.
Such debris in a worst case could trigger a catastrophic engine shutdown, which in turn could lead to the loss of the crew and the shuttle. The problem was serious enough to put a halt to all shuttle processing work and keep the fleet grounded through most of the summer while NASA mobilized its engineering resources to come up with a solution.
By the time the fix was selected and implemented, several weeks had passed and the space agency was forced to shuffle its schedule so that the higher-priority station-related missions would not be delayed too long. Paying the highest price was shuttle Columbia's science research mission, which was delayed from July to next January.
Atlantis wound up targeted for launch in late September, but fixing cracked bearings that were found in the crawler transporters that move the shuttles out to their launch pads at Kennedy Space Center contributed to the agency setting Wednesday, Oct. 2 as the new official launch date.
Mission managers say the repairs to Atlantis' plumbing won't change the way the launch looks or feels.
"From what I saw, it was a very professionally completed process and I feel very comfortable that we're better than we were a few months ago as far as those engines," Ashby said.
Shuttlecam
When the main engines do ignite and Atlantis leaps off its seaside launch pad, viewers of NASA TV will see the blast off from a new angle thanks to a small camera that is mounted to the external tank and is pointing down toward Atlantis' nose.
"Starting with launch, and maybe high on what I'd call the 'wow factor scale,' we're hoping on this flight to get some interesting, new and unique video," said lead shuttle flight director Phil Engelauf.
The camera -- provided by Ecliptic Enterprises Corp., of Pasadena, Calif. -- will be turned on 10 minutes before launch and is expected to provide good pictures during the entire climb to orbit through the external tank separation and for about another six minutes past that.
"We're very optimistic in getting some pretty dramatic video going uphill," Engelauf said.
SPACE.com will provide a live feed of NASA TV via a link from our Shuttle Missions page.
Atlantis' crew is scheduled to end their mission with a landing back in Florida on Oct. 13.
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