NASA's final space shuttle mission, STS-135, is readying for take-off at the Kennedy Space Center in Florida this morning, despite weather concerns that could threaten the launch. At time of writing, the four-strong astronaut crew is taking its seats, ahead of what's expected to be an 11:26am ET flight.
The hatch itself is expected to be closed at 9:21am ET, as Commander Chris Ferguson, Pilot Doug Hurley, and Mission Specialists Sandy Magnus and Rex Walheim ready themselves for take-off. After a briefing with the Spaceflight Meteorology group at Houston, Launch Director Mike Leinbach told his team "we do have a shot at this today."
Interestingly, the last time NASA launched a mission with just four astronauts was back in 1983, with the STS-6. This time, since STS-135 is the final shuttle assembly to be completed, should Atlantis encounter difficulties during the mission there would be no rescue craft available; instead, the STS-135 astronauts would remain on the International Space Station and return to Earth via Russian Soyuz vehicles, a process which NASA says could take almost a year.
Space Shuttle Atlantis is set to commence a 12-day mission to the ISS, where it will deliver components and replacement parts including the Raffaello multi-purpose logistics module, designed to sustain station operations once the shuttles are retired after this flight. Raffaello contains supplies and spare parts. Meanwhile, the crew will also take part in the Robotic Refueling Mission (RRM), an experiment designed to demonstrate and test the the systems required to robotically refuel satellites in space, including those not designed to be serviced.