Amazing ATV Accomplishment

The first fully automated docking with the International Space Station (ISS) has been accomplished by the European Space Agency’s ATV Jules Verne. This resupply and reboost vehicle marks the beginning of Jules Verne’s main servicing mission to deliver cargo, propellant, water, oxygen, and propulsion capacity to the ISS, as well as ESA’s ability to now access the orbital facility by their own means. The 19-ton unmanned spaceship manoeuvred from a holding position 39 km behind the 275-ton space outpost and conducted a 4-hour staged approach, with several stops at reference points for checks. The ATV autonomously computed its own position through relative GPS (comparison between data collected by GPS receivers both on the ATV and the ISS). In close range, the Jules Verne used videometers pointed at laser retroreflectors on the ISS to determine distance and orientation relative to its target. Final approach was at a relative velocity of 7 cm/s with an accuracy of less than 10 cm, all the while both the ATV and the ISS were orbiting at about 28000 km/h some 340 km above the Eastern Mediterranean. ATV Jules Verne’s docking probe was captured by the docking cone at the aft end of Russia’s Zvezda module at 16:45 CEST (14:45 GMT). Docking was completed with hooks closing at 16:52 CEST (14:52 GMT). All the approach and docking phase was piloted by the ATV’s onboard computers under close monitoring by the teams of ESA, CNES (the French Space agency), and Astrium (the prime contractor) at the ATV Control Centre at CNES Toulouse, France, as well as the ISS crew within the Zvezda module. In case of anomaly, both ends could trigger pre-programmed manoeuvres to hold position, retreat to the previous reference point, or escape to a safe distance. The ATV’s behaviour was also under surveillance from its own independent Monitoring & Safing Unit (MSU), which uses a separate set of sensors and computers to check that the approach manoeuvre is conducted safely. In case of major anomaly, the MSU would have been able to take over the commands and order a Collision Avoidance Maneuver (CAM) through dedicated avionics chains and thrusters. As all operations went smoothly, none of these safety maneuvers was required during this afternoon’s approach and docking.