ATV Johannes Kepler Undocks from the ISS

The European Space Agency (ESA) Automated Transfer Vehicle (ATV) Johannes Kepler undocked from the International Space Station (ISS) yesterday, June 20. The spacecraft will soon be destroyed during a fiery reentry over the Pacific Ocean.

Flight planners say that the ATV had to go because a Russian-built Progress space capsule will soon launch to the ISS. The capsule needs the slot that the ATV occupied since late February, 2011.

Since then, astronauts have unloaded the ATV of all its supplies, and replaced them with garbage, or items that are no longer in use. All of the module's current cargo will burn up in Earth's atmosphere.

The undocking process successfully finished at 10:46 am EDT (1446 GMT) on Monday. Johannes Kepler left the aft docking port of the Russian Zvezda module, and was set on a course for reentry.

Perhaps its greatest achievement during its months-long stay at the ISS was the fact that the module managed to use its onboard engines to boost the space lab's orbit up by a few kilometers, thus guaranteeing that the outpost will remain in a stable orbit at least until 2020.

“The ATV, before departing, performed four different re-boost maneuvers, putting the station at nearly its highest altitude of 237 statute miles,” says Kyle Herring, a NASA spokesman, quoted by Space.

During its mission, the second-ever ATV delivered no less than 7 tons of spare parts, experiments, supplies and personal items for the astronauts of Expedition 27/28. It has been docked to the ISS since February 24, having launched from the Kourou Spaceport on February 16.

The spacecraft can weigh up to 22 tons when it's fully loaded and ready to launch. It is about 10.7 meters (35 feet) long, and has a diameter of 4.5 meters, or roughly 15 feet. This means that it's large enough to carry an entire bus inside it.

The Progress 43 spacecraft that will replace the ATV on the ISS will launch today, June 21, from the Baikonur Cosmodrome, in Kazakhstan. Designed and built by the Russian Federal Space Agency (RosCosmos), the capsule is due to take off at 10:38 am EDT (1438 GMT).

The capsule will spend a couple of days catching up to the ISS in orbit. It is scheduled to rendezvous and dock with the space facility on Thursday, June 23, at around 11 am CDT (1600 GMT). It carries about three tons of cargo.

Three weeks from now, the ISS will be set abuzz again, as space shuttle Atlantis is scheduled to arrive around July 10. The orbiter will launch on its final flight on July 8, from the NASA Kennedy Space Center (KSC), in Florida.