ATV2 is now undergoing final testing before its launch from Kourou to the ISS on-board an Ariane 5 in February 2011.
The Automated Transfer Vehicle (ATV) is the most complex cargo spacecraft ever to be developed and built in Europe. Weighing in at 20 tonnes – the size of a double-decker London bus – with a wingspan of 22 metres, despite its size ATV is so precise that it can dock with the International Space Station (ISS) at a speed of 28,000 km/h with an accuracy of just 1.7 cm – and it does so in complete autonomy. The second ATV, named after the 16th century astronomer and mathematician Johannes Kepler, left Airbus Defence and Space Bremen in May this year.
ATV – from development to production
After the successful flight of the Jules Verne ATV1, the ATV production mode is now underway, with the ultimate aim of achieving a shorter construction timetable. "Together with our customer, ESA, we thoroughly analysed the lessons learnt from the highly successful first ATV mission and took them into account for ATV2”, says ATV Programme Manager Olivier de la Bourdonnaye. Airbus Defence and Space is responsible for both the development and production of ATV on behalf of the European Space Agency (ESA). The contract also covers mission preparation as well as operations support. ESA has ordered five ATVs altogether – one to be delivered every 12 months. ATV3, named after the Italian physicist Edoardo Amaldi, is already being integrated in the Bremen cleanroom and its avionics module (EAB) is currently undergoing thermal vacuum testing in Toulouse. However Olivier is convinced that ATV5 is not the end of the road: "We have already submitted a contract proposal for ATV6 and ATV7, allowing ESA to decide the extension of ISS exploitation up to 2020."
ATV system qualification and more usable cargo space
Given the extraordinary accuracy of the first ATV, Johannes Kepler will not be required to go through any demonstration tests. The entire ATV system has been qualified: Jules Verne has demonstrated that the ATV flight control functions are perfectly safe and reliable. The fault tolerance of the communications link between ATV and the Control Centre in Toulouse features up to double redundancy, which provides effective data exchange and seamless flight monitoring. Hence ATV2 will complete a shorter free-flight phase before approaching the ISS, enabling it to reach the International Space Station, more quickly. "The integration teams in Bremen, Les Mureaux and Kourou did a fantastic job", says Olivier. "The spacecraft was delivered on time and in line with the customer’s requirements."
ATV is first and foremost a cargo transportation vehicle and the cargo racks on ATV2 have been improved and are now even lighter. Moreover, the usable cargo space per rack has been increased by 25%. By making optimum use of the space available, more cargo transportation bags (CTB) can now be carried per rack. The facility for late loading has also been optimised – providing a more convenient solution for customers – so that dry cargo can be loaded onto the ATV closer to launch. "Optimising cargo capacity is one of our main priorities since ATV is primarily used to supply the ISS. Further features such as automatic rendezvous and docking with the ISS, along with the associated innovative technology make ATV the most sophisticated cargo spacecraft ever built in Europe", says Wolfgang Paetsch, ATV Programme Implementation Manager at Airbus Defence and Space in Bremen.
ATV – final testing and fuelling in Kourou
At Kourou's spaceport final assembly of the spacecraft, Integrated Cargo Carrier (ICC) – which carries all the re-supply payload and accounts for 60% of the ATV’s volume – solar panels and the Separation and Distancing Module (SDM), which forms the interface between the ATV and Ariane, has been completed. Johannes Kepler is currently undergoing further thorough testing before being loaded with cargo, fuelled and installed within the payload fairing of an Ariane 5 ES – the variant especially adapted to carry the ATV.
The success of missions of this calibre is undeniably down to the outstanding work of the Airbus Defence and Space engineers. "We are fully on schedule. All the teams have really done an excellent job and all the key function tests have been completed successfully", says Wolfgang. "We are now increasingly turning our efforts to getting the different propellants on-board the ATV. The Airbus Defence and Space teams together with our partners are all working flat out in the run-up to launch," the Airbus Defence and Space engineer continues. “We are all looking forward to launching the Johannes Kepler ATV2 in February 2011 and the Edoardo Amaldi ATV3 the following year,” says Olivier. All that now remains is for us is to wish Johannes Kepler a successful mission to the ISS!