Advanced Topics in Astrodynamics

Barcelona, July 5-10, 2004

Use of the Gravitation Capture for the BepiColombo Mission to Mercury

Campagnola S. , Jehn R.

European Space Agency - European Space Operation Center,

Mission Analysis Office, ESA/OPS/GA,

BepiColombo is the ESA cornerstone mission to Mercury. The launch of the spaceprobe is foreseen for the year 2012. The two elements of BepiColombo, a planetary orbiter (MPO) and a magnetospheric orbiter (MMO), will reach their final destination in early 2017 after a long interplanetary trip with long low-thrust arcs and swing-bys at the Moon, Earth, Venus (twice), and Mercury (twice). At arrival to Mercury, a chemical insertion manoeuvre will be performed to insert the two elements into the MMO target orbit (400x12000 km), from where MPO will eventually be inserted into its target orbit (400x1500 km).

Initially the optimum trajectory was determined for a hyperbolic approach. Nevertheless, in the nominal arrival condition a failure of the chemical insertion burn would result in a failure of the mission, as the inadvertent flyby would send the spacecraft away from Mercury. An insertion burn at local noon has the advantage that the spacecraft is kicked into a 11 resonant orbit, with an inexpensive recovery manoeuvre, if the insertion burn fails. However this was disregarded for thermal reason.

The use of the gravitational capture is now considered. Performing extended low- thrust arcs until some 20 days before arrival, the spacecraft will attain very low relative velocity with respect to Mercury, and will orbit temporarily around it before escaping again as a result of the Sun perturbation.

This paper presents some preliminary results and the most interesting trajectories currently under study at the Mission Analysis Office at ESA/ESOC. An estimation of the recovery DV necessary in case of failure of the nominal insertion manoeuvre is also given. A more compete analysis of the problem will soon be published, including a navigation analysis.

 Office B420, ESA/ESOC, Robert-Bosch-Strasse 5, D-64293 Darmstadt, Germany.

Phone: +49-6151-90 2761, fax: +49-6151-90 2625, email: