The next European cargo mission to the International Space Station is preparing for launch, and in this new image, a fuelling operator at Europe’s Spaceport in French Guiana inspects the ATV-4 Albert Einstein as it is filled with propellant. Launch is currently scheduled for June 5, 2013 on an Ariane 5ES rocket to bring about 7 tons of cargo the ISS, including fuel to give the space station an orbital re-boost.
These Automated Transfer Vehicles (ATVs) bring other supplies such as equipment, experiments, water, air, nitrogen, oxygen and fuel.
As the ISS circles Earth, it slowly loses altitude, and occasionally needs a boost to keep it in the proper orbit. ATVs, Progress resupply ships and the thrusters on the Zvezda service module are used to re-boost the station; Soyuz spacecraft are also used “in a pinch” said Johnson Space Center News Chief Kelly Humphries, but they mainly want to save the Soyuz fuel for the departing crew heading back to Earth.
Watch this video as astronaut Jeff Williams demonstrates the acceleration experienced inside the cabin during a reboost on January 24, 2010 (the acceleration starts about 3:50 in the video):