The robotic arm on the International Space Station released the SpaceX Dragon early this morning, sending the capsule on its way home.
The Dragon capsule, loaded with about 2,600 pounds of used hardware, completed experiments and trash, is expected to splash down in the Pacific Ocean around 12:34 p.m. EDT.
The capsule has been attached to the space station for more than three weeks.
The spacecraft originally was scheduled to return to Earth on Monday, but the trip was postponed a day because of bad weather near the splashdown site in the Pacific Ocean.
This morning, astronauts used Canadarm2, a robotic arm on the space station, to release the Dragon at 6:56 a.m. The Dragon will fire its engines for the last time at 11:42 a.m., sending it through the Earth's atmosphere for its planned splashdown.
The Dragon capsule blasted off atop a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station in Florida on March 1. The spacecraft, which ferried 1,268 pounds of scientific experiments and supplies for the space station, was scheduled to rendezvous with the orbiter the next day but needed an additional day for the rendezvous after a problem with the craft's thruster system delayed its schedule.
A successful commercial mission is a major milestone for NASA, which now depends on commercial flights since retiring the agency's fleet of space shuttles in the summer of 2011.
For the foreseeable future, NASA will need commercial missions to ferry supplies, and possibly even astronauts, to the space station, while the space agency focuses on developing robotics and big engines in preparation for missions to the moon, asteroids and Mars.
This latest mission is the second of 12 SpaceX flights contracted by NASA to resupply the space station. It also will be the third trip by a Dragon capsule to the orbiting laboratory.
SpaceX made a demonstration flight in May 2012 and launched the first official resupply mission in October, delivering 882 pounds of supplies to the space station.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+, or subscribe to Sharon's RSS feed . Her email address is firstname.lastname@example.org.