Space Shuttle Discovery to Launch Today

CAPE CANAVERAL, Fla. - NASA?s shuttle Discovery and its seven-astronaut crew are poised to rocket spaceward this afternoon carrying the largest laboratory ever built for the International Space Station.

Discovery is counting down toward a 5:02 p.m. EDT (2102 GMT) liftoff from a seaside launch pad here at NASA?s Kennedy Space Center (KSC). The seven crewmembers of the shuttle?s STS-124 mission are planning to deliver Japan?s $1 billion Kibo laboratory module - a room the size of a large tour bus - to the International Space Station (ISS).

Veteran astronaut Mark Kelly will command the planned 14-day mission, leading five rookies and one other veteran spaceflyer, mission specialist Mike Fossum, to the orbital laboratory. The first-timers include pilot Ken Ham and mission specialists Karen Nyberg, Ron Garan and Greg Chamitoff, as well as Japanese astronaut Akihiko Hoshide of the Japan Aerospace Exploration Agency (JAXA). Kelly said he?s not worried about any lack of experience.

?They have experience, it?s just not experience in space yet, but they?re going to get that on flight day one,? he said in a preflight interview. ?We will get everything done in a professional manner, they?re all very highly trained, and it?s not something I even really think about?? We?ve got a complicated, busy mission ahead of us.?

Mission managers are hopeful that Discovery will be able to launch today as planned. There is currently an 80 chance of good weather for today?s liftoff attempt, shuttle weather officer Kathy Winters said on Friday.

?Right now the weather overall is looking promising,? Winters said. ?The first day [Saturday] is the best day weather-wise.?

If the space shuttle does not blast off today, the weather forecast deteriorates for subsequent launch opportunities on Sunday and Monday, she said.

Packed mission

While in space, Discovery?s STS-124 astronauts plan to perform three spacewalks outside the station to set up the new Kibo lab and activate its robotic arm, the Japanese Remote Manipulator System. They will also move Kibo's smaller attic-like module from its temporary station to attach it to the new 37-foot (11 meter) main module.

Japan Aerospace Exploration Agency astronaut Hoshide will serve as the local expert on Kibo?s ins and outs while the crew installs the ISS?s new addition.

?An exciting mission is coming up,? he said upon arriving in Florida on Wednesday. ?I?d just like to thank all the hard work that all the Japanese people have been doing on the Japanese module. It?s going to be a great mission and very exciting, especially for the Japanese people.?

Discovery?s flight will be NASA?s third shuttle trip this year, and the second of three missions to assemble Japan?s entire 15.9-ton Kibo facility, whose name means "hope" in Japanese. The lab?s storage module arrived during a previous March shuttle mission, and a February flight installed Europe's Columbus laboratory. A third Kibo mission, set to fly in 2009, will deliver a porch-like exterior platform for external space experiments.

One of the astronauts slated to launch today will swap places with a current ISS crewmember and stay on for a long duration stint. Chamitoff will relieve American astronaut Garrett Reisman as a flight engineer for the space station's Expedition 17 crew. Reisman is set return to Earth aboard Discovery on June 14, while Chamitoff is currently due home during a planned November shuttle flight.

?I feel very lucky to be a part of this crew and a part of this mission,? Chamitoff said on Wednesday. ?The assembly and attachment of the Japanese Experiment Module to the ISS is going to be a real historic turning point for Japan? It?s also a landmark point for NASA, because after this point we have the operations with all the different international partners.?

Discovery?s launch will also represent a landmark flight for NASA?s overhaul of the space shuttle external fuel tanks since the Columbia disaster. After that shuttle?s heat shield was fatally damaged by falling debris from its external tank during launch, the agency redesigned the tanks for safety. Discovery?s trip will be the first to fly with an external tank built from the ground up with the new safety features in place.

A few notable recent additions to Discovery?s payload will also mark the flight.

Onboard the shuttle is a replacement pump for the space station?s broken toilet, which is currently working only sporadically. NASA also packed away a toy action figure of the Disney-Pixar character Buzz Lightyear from the movie ?Toy Story,? as part of an educational partnership with Disney. The doll will be used to demonstrate the laws of physics in flight to get kids interested in science and exploration, NASA and Disney representatives said.

NASA will broadcast the planned launch of Discovery's STS-124 mission live on NASA TV, beginning at 12:00 p.m. EDT (1600 GMT) on Saturday. Click here for SPACE.com's shuttle mission updates and NASA TV feed.

• New Video: STS-124 Mission Preview ? Delivering Kibo
• Video: STS-123 Mission Rewind: Launch to Kibo Attic Delivery
• The Space Shuttle Countdown Quiz