After a flight of 4 million kilometres in space lasting almost a week, ATV-2 “Johannes Kepler”, the second unmanned supply vehicle built by Astrium for the European Space Agency (ESA), has executed a perfect manoeuvre to dock automatically with the International Space Station (ISS). The Automated Transfer Vehicle (ATV) successfully attached to the ISS at 4.59 pm CET and is now on target to accomplish its ISS supply and orbit-raising mission, where it will become an integral, inhabited part of the ISS.

“This is a great day for Astrium as we are prime contractor for the highly complex ATV payload. Given its ability to dock automatically with the ISS at a speed of 28,000 km/h, the ATV is currently the most intelligent space robot in the world”, said Dr. Michael Menking, Head of Orbital Systems and Space Exploration at Astrium. “ The sophisticated space vehicle, which is an upper stage, satellite and space station module rolled into one, provides an excellent baseline for future robotic innovation and manned exploration missions.”

ATV-2 “Johannes Kepler” brings over 7 metric tons of net freight for the space station, including 850 kilograms of fuel, 100 kilograms of oxygen and more than 1.6 metric tons of stores and provisions. ATV-2 “Johannes Kepler” also brings clothing for the astronauts, scientific experiment Geoflow II, built by Astrium for ESA, as well as various items of equipment that are necessary for conducting repairs and for the general operation of the ISS. The ATV additionally carries 4.5 metric tons of fuel for the re-boost manoeuvres which will lift the ISS to an altitude of approximately 400 kilometres.

“The ATV is a tangible proof of the technologically sophisticated space systems that Astrium, as a truly European company, can provide. Our teams in Germany and France worked together in perfect harmony, supported by superb suppliers all around the continent. We are very proud that the fully-automatic docking procedure – the highlight of the mission – passed off without a hitch. We sincerely thank European governments, ESA and national agencies for their support and confidence in Astrium’s teams”, said Alain Charmeau, CEO of Astrium Space Transportation, on successful completion of the docking manoeuvre.

In around three and a half months time, Johannes Kepler’s mission will end with it being loaded up with waste, then undocking, de-orbiting and destruction as it burns up in the dense layers of the Earth’s atmosphere.

Docking with the ISS

Given the extraordinary accuracy of the first ATV “Jules Verne” launched and docked in 2008, “Johannes Kepler” was not required to go through any demonstration tests. Therefore, ATV-2 completed a shorter free-flight phase before approaching the ISS, thus enabling it to reach the ISS in just one week.

Johannes Kepler docked with the Russian station module “Zvezda”. The safety of the crew and the space station is the number one priority during the automatic docking sequence with the ISS. During the flight, the ATV’s onboard systems are constantly monitored by the ATV Control Centres. The autonomous, intelligent ATV safety system – developed by Astrium – ensures that in case of even the slightest system anomaly, the space vehicle automatically returns to a safe position vis-à-vis the station and “parks” at an appropriate distance from the ISS. After system verification, a new approach can then be initiated.

The docking phase began at nearly 30 km from the ISS. At a distance of 250 metres, the ATV system switched to guidance, navigation and control mode (GNC) which uses optical sensors. In addition to the already existing radio connection, the astronauts onboard the ISS have been able to directly follow the docking manoeuvre by video. After authorisation by the control centre, the ATV continued its approach to 12 metres and covered the last few metres to the ISS docking port at a relative maximum speed of not more than ten centimetres per second. The ATV’s extended docking probe has a diameter of about 15 centimetres and needs to be captured by the docking port of the Russian “Zvezda” module which has a diameter of 90 centimetres.

ATV-2 aligned to the longitudinal axis of the ISS. All the electrical, mechanical and fluid connections between the ISS and the space vehicle were set up automatically. A cargo hatch with a diameter of almost 72 centimetres connected the Integrated Cargo Carrier with the Russian service module and made the European space vehicle an integral part of the ISS.

Source: EADS press release