CAPE CANAVERAL, Florida -- More than three weeks after arriving at the International Space Station, the SpaceX Dragon spacecraft is ready for the trip back to Earth, now scheduled for Tuesday, March 26, 2013.
NASA says that Dragon's return date, originally scheduled for March 25, was postponed due to inclement weather developing near its targeted splashdown site in the Pacific Ocean. The additional day spent attached to the orbiting laboratory will not affect science samples scheduled to return aboard the spacecraft.
The actual removal of Dragon from the space station begins at 4:05 a.m., with release scheduled for 7:06 a.m. Dragon will conduct a series of engine burns to take it away from the space station with the third and final departure burn taking place around 7:16 a.m.
Dragon will be detached from the Earth-facing side of the station's Harmony module and unberthed by Expedition 35 Flight Engineer and NASA astronaut Tom Marshburn. Expedition 35 Commander Chris Hadfield of the Canadian Space Agency will back-up Marshburn and monitor Dragon's systems during the activity.
Marshburn, working from the robotic work station in the space station's cupola, will maneuver the station's robotic arm for the release of the spacecraft.
Dragon is the only space station resupply spacecraft able to return to Earth intact. It will return about 2,668 pounds (1,210 kilograms) of science samples from human research, biology and biotechnology studies, physical science investigations and education activities.
During launch, the capsule carried about 1,200 pounds of supplies for the space station crew and experiments being conducted aboard the orbiting laboratory.
Experiment samples coming back to Earth will help researchers continue to assess the impact of long-duration spaceflight on the human body. Returning plant samples will aid in food production during future long-duration space missions and enhance crop production on Earth. Crystals grown aboard and returning from the station could help in the development of more efficient solar cells and semiconductor-based electronics.
Dragon’s deorbit burn will take place approximately 11:40 a.m. with splashdown scheduled for 12:36 p.m. about 246 miles off the coast of Baja California. Dragon will take about 30 hours to return to port, at which point several critical science samples will be handed over to NASA for a return trip back to Houston that day.
The mission is the second of 12 SpaceX flights contracted by NASA to resupply the International Space Station. It is the third trip by a Dragon capsule to the orbiting laboratory, following a demonstration flight in May 2012 and the first resupply mission in October 2012.
PHOTO: SpaceX photo of first Dragon splashdown.