21 Mar 2003

Each has been looked at on the basis of the expected scientific return, the technical risks related to using the Rosetta design in the new mission, and the minimisation of costs.

Of the nine mission scenarios studied by the Rosetta Science Working Team, three have survived to this point and were presented to the delegations of the ESA Member States through the Science Programme Committee at its meeting on 25-26 February 2003. Two mission scenarios (in February 2004 and 2005 respectively) would take Rosetta to a new target comet, Churyumov-Gerasimenko, while another (in January 2004) would take it to its original target, Comet Wirtanen.

All options are now being studied in more detail so that the final decision can be made. A campaign of observations using both the NASA/ESA Hubble Space Telescope and the instruments of the European Southern Observatory is under way to study Comet Churyumov-Gerasimenko. In this way, astronomers will be able to characterise the comet and perform a mission analysis, also to identify landing scenarios and make a thorough assessment of any hardware modification that would be necessary.

In parallel, ESA is also performing an assessment of the launch requirements for the various mission scenarios. This will include looking at alternatives to Ariane as back-up options, such as the Russian Proton rocket.

The final decision on Rosetta's new mission scenario will be made by the ESA Science Programme Committee in May 2003.

Note to editors

Following the failure of the Ariane launch 157 in December 2002, with the loss of two spacecraft, ESA and Arianespace took the joint decision not to launch Rosetta during its January 2003 launch window. As a result of this decision, Rosetta could no longer follow its originally intended mission to Comet Wirtanen.

For more information, please contact:

ESA Communication Department
Media Relations Office
Paris, France
Tel: +33 (0)1 5369 7155
Fax: +33 (0)1 5369 7690

Roberto Lo Verde
Head of ESA Science Programme
Communication Service
Tel: +31 (0)71 565 5279
E-mail: roberto.lo.verdeesa.int