Posted: Tuesday, February 26, 2008
Europe will receive its own access to the International Space Station (ISS) by means of the Automated Transfer Vehicle (ATV) space transporter. As the most complex spacecraft ever to be built in western Europe, the ATV represents a significant milestone for European space. The German Aerospace Center (DLR) in Oberpfaffenhofen is coordinating the communication between the ATV control centres, located throughout the world. In addition, the German re-igniteable upper stage engines of Ariane 5 were tested at the DLR facility in Lampoldshausen.
The first ATV, which commenced its journey to the ISS in March 2008, is named after the French visionary and science fiction author Jules Verne. Four additional ATV flights are planned for 2009, 2011, 2012 and 2013.
Six tonnes of supply freight for the ISS from Europe
The Automated Transfer Vehicle is an unmanned spacecraft that can transport freight to the ISS. It is approximately ten metres long and has a diameter of 4.5 metres. With its solar panels unfolded the ATV has a span of over 22 metres. The total mass of the Jules Verne when loaded and ready to launch is almost 20 tonnes. The net payload capacity of an ATV is at present approximately six tonnes. The composition of the freight varies from mission to mission. In addition to food and other supply goods the ATVs can also transport scientific equipment, replacement parts and experiments to the ISS.
The vehicle consists of one section for the drive and the avionics - the electronic steering devices. In addition it has a load-bearing segment, permanently under pressure, in which dry freight is conveyed. This is situated in so-called ISPRs (International Standard Payload Racks), which means it is packed such that it can be easily stored on the ISS. Astronauts enter the pressurised segment when unloading and loading the ATV from the station.
Independent docking at the ISS
All ATVs are launched by Ariane 5 rocket from Kourou, French Guyana using a re-igniteable upper stage. As a result of the ATV flights, the Ariane 5 is now also an element of the logistics plan for the ISS. After separating itself from the upper stage the ATV performs the required rendezvous and docking manoeuvre at the space station by itself, monitored by the ATV control centre in Toulouse.
ATV can correct the space station's orbit
The ATV docks at the Russian station module Swesda, where it can stay for six months. Similar to the Russian transporter Progress, the ATV can lift the ISS to a higher orbit from here using its main rocket motors. This is necessary from time to time as the space station is continuously slowed down by the resistance of the residual atmosphere and loses around 200 metres a day in orbit height. At the end of the mission the ATV will be loaded with up to 6.5 tonnes of waste from the ISS. After undocking from the ISS it will re-enter Earth's atmosphere under supervision and finally burn up over the Pacific.
The ATV flights are the European contribution to supplying the ISS. The greater amount of the ISS operating costs that Europe is to bear on a pro-rata basis will be compensated in the form of contributions in kind instead of currency payments to NASA. The total development costs for the ATV amount to approximately 1.35 billion euro. This includes the prototype (ATV 1 Jules Verne at around 1 billion euros), the ground segment, adapting the Ariane 5 launch vehicle, and the launch vehicle itself. German companies are receiving orders to a total value of around O240 million for the Jules Verne project alone.
Whether or not there will be further missions after the four ATV missions planned up to 2013 will not least depend on the success of the scientific utilisation of the ISS. If Europe decides to make use of the research opportunities on the ISS - mainly in the Columbus laboratory - for longer than until 2013, additional ATV flights could still take place.
Worldwide web of control rooms
The ESA's ATV control centre in Toulouse is monitoring the mission in collaboration with the NASA control centres in Houston and Roskosmos in Moscow. DLR's control centre in Oberpfaffenhofen near Munich is also involved as headquarters of the so-called Interconnection Ground Subnetwork. Engineers and technicians work in three additional control rooms in Toulouse and monitor the ATV. Around 90 minutes prior to the spacecraft reaching the outer ISS safety zone, a two kilometre radius around the station, the responsibility for the mission is transferred to the control centres in Houston and Moscow until such time as the craft docks.
ATV-1 Jules Verne in facts and figures
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