This story was updated at 11:43 a.m. EDT.
A European robotic spaceship undocked from the International Space Station today (June 20) to make way for an incoming Russian cargo craft expected later this week.
The huge Automated Transfer Vehicle-2 (ATV-2) separated from the orbiting laboratory at 10:46 a.m. EDT (1446 GMT). The ship, named the "Johannes Kepler," is packed with trash and unneeded cargo that will be intentionally destroyed along with the vehicle when it re-enters Earth's atmosphere.
The European Space Agency supply ship spent about four months docked at the space station, after arriving on Feb. 24. It delivered 7 tons of cargo to the outpost, including experiments, fuel, water, food and other supplies. [Video: ATV-2 Johannes Kepler's Fiery Finale Explained]
The craft is the second robotic cargo spacecraft built by the European Space Agency, and was named after the 17th century German astronomer who formulated famous laws of planetary motion.
The cylindrical vehicle is about 35 feet (10.7 meters) long and 14.7 feet (4.5 meters) wide. In all the ATV-2 weighed 22 tons (about 20000 kilograms) at launch, and is big enough to fit a double-decker bus inside.
Before undocking, the vehicle fired its engines to boost the International Space Station to a higher orbit.
"The ATV, before departing, performed four different re-boost maneuvers, putting the station at nearly its highest altitude of 237 statute miles," said NASA spokesman Kyle Herring.
A new Russian resupply spaceship is planned to launch out of Kazakhstan's Baikonur Cosmodrome on Tuesday (June 21) at 10:38 a.m. EDT (1438 GMT). The Progress 43 vehicle will dock at the space station on Thursday (June 23).
Six spaceflyers — commander Andrey Borisenko and flight engineers Alexander Samokutyaev and Sergei Volkov of Russia, as well as Ron Garan and Mike Fossum of NASA and Japan Aerospace Exploration Agency astronaut Satoshi Furukawa — currently live onboard the International Space Station, serving on the Expedition 28 mission.
In addition to orchestrating the departure and arrival of their unmanned delivery ships, the station residents are preparing for the final visit from a space shuttle. The shuttle Atlantis will launch on July 8, carrying four astronauts and a haul of spare supplies on a 12-day trip to the station.
During the shuttle mission, Fossum and Garan plan to conduct a spacewalk to perform maintenance outside the space station.
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Clara Moskowitz is a science and space writer who joined the Space.com team in 2008 and served as Assistant Managing Editor from 2011 to 2013. Clara has a bachelor's degree in astronomy and physics from Wesleyan University, and a graduate certificate in science writing from the University of California, Santa Cruz. She covers everything from astronomy to human spaceflight and once aced a NASTAR suborbital spaceflight training program for space missions. Clara is currently Associate Editor of Scientific American. To see her latest project is, follow Clara on Twitter.