A group of four astronauts boarded the space shuttle Atlantis this morning in anticipation of a planned 11:26am launch, despite the possibility of a weather delay.
Commander Chris Ferguson, Pilot Doug Hurley, and mission specialists Rex Walheim and Sandy Magnus arrived at the launch pad just before 8am this morning, and started boarding the shuttle at 8:06am.
There is still a 70 percent chance that inclement weather could disrupt today's launch. NASA officials are concerned about showers and thunderstorms within 20 nautical miles of the shuttle landing facility, flight through precipitation, and cumulus clouds. In a statement, however, launch director Mike Leinbach said, "we do have a shot at this today."
The teams have not uncovered any technical details that would delay today's launch, NASA said. Yesterday, however, the team delayed the rollback of the protective rotating service structure (RSS) after severe thunderstorms rolled through the area. Two lightning strikes hit near the launch pad; one struck the water tower 515 feet from the pad, while another struck the beach northeast of the pad.
After NASA determined the the lightning did not damage anything on or near the shuttle, technicians started moving the RSS at 2:38pm Thursday. At 2:01am this morning, officials started fueling Atlantis with 535,000 gallons of super-cold liquid hydrogen and liquid oxygen, a process that ended at 4:58am.
This, of course, is the final launch for NASA's space shuttle program, after more than 30 years. After Atlantis completes its nearly two-week mission, journeys to the International Space Station will become commercial endeavors. This time around, however, Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics, and spare parts to the ISS.
To watch today's launch, NASA has a live feed of all the proceedings on NASA TV. It will also air via Ustream on spacevidecast.com (below) and via spaceflightnow.com.
If you can't watch, follow on Twitter via @NASA, @NASATweetup, @NASA_Johnson, and @NASA_Kennedy.
Update: Atlantis launched successfully at 11:29am Eastern. For more see, NASA's Space Shuttle Program: A Look Back.