The second unmanned European cargo spacecraft for the International Space Station (ISS) is being tested for flightworthiness and functionality as a fully integrated unit for the first time.
The Johannes Kepler, as the Automated Transfer Vehicle (ATV) is dubbed, is being tested at Astrium’s facility in Bremen.
The delivery date for Johannes Kepler has been slated for November 2010. Astrium is working on behalf of the European Space Agency (ESA) on the development and production of ATVs. Astrium has been contracted to produce a further three ATV transport vehicles for the ESA by 2015.
‘After successfully integrating the propulsion module and avionics unit into the spacecraft over the last month, we can now start testing Johannes Kepler as a complete unit for the first time,’ said Astrium’s Michael Menking, senior vice-president and head of orbital systems and exploration. ‘To do that, the spacecraft and logistics modules will be connected to each other in a soft configuration, i.e. using electrical connecting cables.’
The purpose of these tests is to verify the functionality and flightworthiness not only of the hardware components but also of the flight software. The latter is responsible for the entire mission management and particularly the fully automatic docking to the ISS.
Johannes Kepler is one of the largest ATVs ever developed as a joint European project and it must meet high safety requirements for human space flight. Therefore the spacecraft’s digital and electronic architecture has been built with double redundancy. A fault-tolerant central computer – consisting of three computer modules – is designed to smoothly execute the mission.
The spacecraft will be shipped to the European Spaceport in Kourou, French Guiana, in the second quarter of 2010. Here, the ATV, Integrated Cargo Carrier (ICC), solar panels and the Separation and Distancing Module (SDM), which forms the interface between the ATV and the Ariane launcher, will undergo final assembly.
It will then undergo a further series of extensive tests on site before being installed in the payload bay of an Ariane 5 launch system.
‘If everything runs to plan, we will be able to launch our second mission to the ISS in November 2010,’ Menking added.
The ATV is the supply spacecraft for the ISS. On a typical mission, the ATV will carry water, fuel, food and scientific equipment to the ISS. Once its mission is over, the ATV is loaded with waste, undocked from the ISS and allowed to burn up upon re-entry into the Earth’s atmosphere.
While still docked with the space station, the ATV is also responsible for regularly boosting the ISS into a higher orbit and performing manoeuvres to avoid collisions with space debris. This is necessary because the ISS orbits at an altitude of around 400km in a region where it is slowed down by the residual atmosphere, causing it to lose altitude.
As part of an ESA study, Astrium is conducting research into a reusable Advanced Re-entry Vehicle (ARV) based on ATV technology.
A total of €21m (£18.9m) is being invested in this preliminary phase of ESA’s ARV programme.