Europe's Johannes Kepler ATV cargo ferry undocked from the International Space Station Monday at 14:46:30 GMT (16:46:30 CEST). The craft is now leaving the orbital outpost far behind and will end its mission on Tuesday evening as a shooting star over the Pacific Ocean.

After spending almost four months as an important part of the International Space Station, ESA's second Automated Transfer Vehicle is ending its days as a rubbish truck - another critical role because the 1200 kg of waste bags and discarded equipment cannot just be thrown out of the Station. The crew closed the hatches between the two vehicles on Sunday afternoon at 15:30 GMT (17:30 CEST).

Undocking came, with ATV's thrusters gently increasing the distance from the outpost, towards a path leading to its deliberate destruction. Before the undocking, all electical and data connections between the two spacecraft were disconnected at 14:39 GMT (16:39 CEST).

ATV Johannes Kepler delivered more than seven tonnes of dry cargo, propellants and air in February.

ATV's last major job was to boost the complex to a higher orbit. The vehicle also assisted Station attitude control several times during its mission.

Fireball over the Pacific
On Tuesday, Johannes Kepler will fire its engines twice to descend from orbit.

The first burn, at 17:07 GMT (19:07 CEST), will drop it towards Earth. The second burn, at 20:52 GMT (22:52 CEST), will direct it precisely towards its South Pacific target.

This area is used for controlled reentries of spacecraft because it is uninhabited and outside shipping lanes and airplane routes. Extensive analysis by ESA specialists will ensure that the trajectory stays within safe limits.

The same area was also used for the descents of ATV-1 in September 2008 and Russia's Mir space station in 2001.

Air and sea traffic has been warned and a no-fly zone will prevent any accidents.

The 14-tonne ATV is now empty of hazardous materials and it will almost completely burn up - like a meteor, hitting the atmosphere at high speed.

Each year, about 40 000 tonnes of meteoroids and interplanetary dust fall to Earth with no ill effect.

The freighter will hit the outer layers of the atmosphere at an altitude of about 100 km. It will start tumbling at about 20:24 GMT (22:24 CEST), disintegrate, burn and any remains will strike the ocean at around 20:59 GMT (22:59 CEST).

Only a few hardy pieces might survive the fiery reentry and splash harmlessly into the ocean.

Last call home
The last moments of Johannes Kepler will be carefully captured by its Reentry Breakup Recorder, collecting information on its position, attitude, temperature, pressure and other aspects of its breakup.

The 9 kg 'black box' will start recording automatically for ATV's last five minutes.

It will then be jettisoned, protected by its own heatshield. At an altitude of 18 km it will transmit the stored data via the Iridium satphone system for analysis. The recorder will not be recovered.

Some aspects of controlled destructive entries are still not well known so all in-situ measurements are welcome.

Similar recorders may be used in future on satellites and spacecraft like black boxes on aircraft.

related report
ATV-2 Undocks; Spacewalk Preps, Science, Maintenance for Crew
Houston TX (SPX) Jun 20 - Filled with trash and unneeded cargo, the "Johannes Kepler" Automated Transfer Vehicle-2 (ATV-2) undocked from the aft port of the International Space Station's Zvezda service module at 10:46 a.m. EDT Monday and will be deorbited for a destructive re-entry in Earth's atmosphere. The European Space Agency supply ship delivered seven tons of cargo when it docked on Feb. 24.

The undocking makes room for the ISS Progress 43 cargo ship which is scheduled to launch Tuesday at 10:38 a.m. from the Baikonur Cosmodrome in Kazakhstan, docking to the aft port of the Zvezda service module two days later.

Meanwhile inside the station, Expedition 28 Flight Engineer Ron Garan spent some time working in the Quest airlock to resize the spacesuits that will be used during the upcoming STS-135 mission of space shuttle Atlantis to the station. Garan and Flight Engineer Mike Fossum, both veteran spacewalkers, will make an excursion during the mission.

Commander Andrey Borisenko worked with the Coulomb Crystal experiment, which studies dynamic and structural characteristics of the Coulomb systems formed by charged dispersed diamagnetic macroparticles in a magnetic trap. Coulomb systems are structures following Coulomb's Law, a law of physics describing the electrostatic interaction between electrically charged particles. It was essential to the development of the theory of electromagnetism.

Alexander Samokutyaev, also a flight engineer, performed routine maintenance on the environmental control and life support system in the Zvezda service module.

The three newest Expedition 28 crew members - Fossum and Flight Engineers Sergei Volkov and Satoshi Furukawa - continued their onboard orientation, learning the layout of the station and continuing to familiarize themselves with the orbiting laboratory's operations.

The crew members took part in a drill to practice for the unlikely event of an emergency that would require that they exit the orbital complex.

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