Two days after a SpaceX Dragon cargo craft left the International Space Station and returned to Earth, Orbital Science Corp.'s Cygnus cargo spacecraft is getting ready for a Monday launch.
Carrying about 5,000 pounds of crew provisions, spare parts and scientific experiments, Cygnus is set to ride on an Antares rocket that is scheduled for liftoff from NASA's Wallops Flight Facility in Virginia at 6:45 p.m. ET.
The launch will be the Orbital Science Corp.'s third commercial resupply mission.
A launch readiness review performed on Sunday showed that all systems were functioning as planned. With a 98% chance of favorable weather, NASA gave a "go" for the Monday launch.
On Saturday, one of the space station's robotic arms released the Dragon cargo spacecraft at 9:57 a.m. ET. Using a series of burns and maneuvers, the capsule safely moved away from the orbiter and began its return trip.
Dragon, which arrived at the space station on Sept. 23, returned carrying more than 3,276 pounds of cargo, including science samples from human research, biology and biotechnology studies and physical science investigations.
NASA reported that the cargo craft splashed down in the Pacific Ocean at 3:39 p.m. ET a few hundred miles west of Baja California, Mexico.
The Dragon's return wrapped up SpaceX's fourth contracted cargo resupply mission to the space station. SpaceX has a contract to make eight more resupply trips to the station.
NASA's contract with Orbital Science provides for five more resupply missions after this one.
Since NASA retired its fleet of space shuttles in 2011, the space agency has been relying on commercial companies to ferry supplies to the space station.
NASA also has a deadline of launching astronauts from U.S. soil by 2017.
To move that effort forward, last month NASA awarded highly sought after commercial crew transportation contracts to SpaceX and the Boeing Co.. The contracts are to build spacecraft that will carry astronauts from Cape Canaveral to the space station and back.
By being able to launch astronauts from U.S. soil again, NASA would end its dependence on Russia to carry its astronauts to the station. The U.S. has been paying the Russian space agency about $70 million per astronaut.