Atlantis is scheduled to go on a 12-day mission, carrying only four astronauts (compared to the usual crew of six or seven). During the mission, it will visit the International Space Station, drop off about 9,500 pounds of supplies and spare parts and conduct an experiment to test new refueling and repair technology for satellites in orbit.
The weather forecast was far from optimal hours before launch though — showers and thunderstorms were predicted to be present in the launch area, and NASA had said there was a 70% chance of delay. If that would have happened, NASA would have rescheduled for a Saturday and Sunday launch.
Space shuttle Endeavour, which successfully ended its last mission on June 1, was to be the last aircraft in NASA’s space shuttle program, but another mission was approved in October 2010.
Live Shuttle Launch :
Source : http://mashable.com/2011/07/08/shuttle-launch-atlantis-video/
