MOSCOW—The European Space Agency says its cargo craft has successfully undocked from the International Space Station after a failed separation caused by communication problems earlier in the week.

The ATV-3 detached from the Russian service module early Saturday and is expected to leave orbit and be jettisoned Tuesday into an unpopulated area of the South Pacific. The ATV-3 launched in March from a facility in the South American country of French Guiana with more than seven tons of food, water and other supplies for the space station.

It has been loaded with waste for disposal. Three astronauts are set to travel to the space station next month, bringing to six the number of crewmembers at the orbiting laboratory.