Technology driver-the Rosetta mission

The Rosetta mission is a cometary mission, which will be launched in 2003 by Ariane 5. After a long cruise phase, the satellite will rendezvous with Comet Wirtanen and orbit it, while taking scientific measurements. A Surface Science Package (SSP) will be landed on the comet surface to take in-situ measurements. During the cruise phase, the satellite will be given gravity assist manoeuvres once by Mars and twice by the Earth. The satellite will also take measurements in the fly-bys of two asteroids. The Rosetta mission has characteristics differing quite considerably from those deep space missions hitherto supported at ESOC. One of these is the use of packet telemetry and packet telecommanding. Rosetta is the first ESA deep space mission using these standards. This paper describes in detail how the Rosetta on-board and ground segment design uses packetised telemetry and commands taking into account the deep space characteristic of the Rosetta mission. In particular the paper describes how Rosetta is designed to overcome two major problems with deep space missions, the relative low downlink rate and the long turnaround time for telecommands.