This mission's flight segment is constituted of:
- an orbiter, Airbus Defence & Space (initially Matra Marconi Space) with the participation of Thales Alenia Space (initially Alenia Spazio) for integration and testing, for the European Space Agency.
- a lander, developed by a consortium of eight European countries (Germany, France, Italy, Great-Britain, Hungary, Austria, Ireland, Finland).
Each of both spacecraft has a scientific payload composed of instruments developed by European or American scientific laboratories: 11 instruments for the Orbiter, and 10 instruments for the Lander. For more details about those instruments, see ESA's Rosetta website.
Due to the required performances (launch mass and escape velocity), an ARIANE-5 launcher was used. The launch took place on 2 March 2004.