1. 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. HYPERBOLIC APPROACH 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 late 2016. In its long interplanetary trip, BepiColombo will exploit low-thrust arcs provided by the Solar Electric Propulsion Module (SEPM), as well as swingbys at the Moon, Earth, Venus (twice), and Mercury (twice). THE BEPICOLOMBO MISSION TO MERCURY A DVANCED T OPICS IN A STRODYNAMICS Barcelona, July 5-10, 2004 USE OF GRAVITATIONAL CAPTURE FOR THE BEPICOLOMBO MISSION TO MERCURY Stefano Campagnola, Rüdiger Jehn Mission Analysis Office ESA/ESOC, Darmstadt, Germany Stefano.Campagnola@esa.int GRAVITATIONAL CAPTURE The use of the gravitational capture is now considered. Performing extended low-thrust arcs until some 30 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. Two interesting cases are presented here. More results and further analysis will soon be published. Launch Date 3 May 2012 Lunar Flyby Date 23 Jul 2012 Arrival Date 26 Nov 2016 SEP consumption 6.46 (7.65*) km/s CH consumption 0.355 (0.398*) km/s Maximum Thrust (SEPM) 400 mN Cruise Time 4.35 years (1589 d) Initially the optimum trajectory was determined for a hyperbolic approach. However 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. Tab 2 : Summary of the hyperbolic approach * including navigation, margin, corrections for non-nominal arrival conditions 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) f MERCURY at arrival 60°<f ME <120°, 240°<f ME <300° i MMO / MPO 90 ° MMO / MPO 0°0°0°0° h periherm MMO / MPO 400 km h apoherm MMO 12000 km h apoherm MPO 1500 km MMO 178 ° MPO 196 ° Tab 1 : Target orbits for MMO and MPO Fig 3 : Hyperbolic approach and target orbits Fig 2 : Definition of the angle Giuseppe “Bepi” Colombo Fig 4 : Incoming and recovery trajectories for case A in a Mercury equatorial reference frame (upper left and lower right) and in a rotating reference frame (lower left) CASE A (left) Nominal Arrival Date: 5 Jan 2017 MJD2000 6214.4 Arrival osculating orbit: 400x200000 km CASE B (right) Nominal Arrival Date: 5 Jan 2017 MJD2000 6214.9 Arrival osculating orbit: 400x180000 km Fig 5 : Incoming and recovery trajectories for case B in a Mercury equatorial reference frame (upper right and lower left) and in a rotating reference frame (lower right) To the Sun 1 st V Rec (~1 m/s) 2 nd V Rec (~40 m/s) To the Sun 1 st V Rec (~1 m/s) 2 nd V Rec (~3 m/s) 3 rd V Rec (~5 m/s) Fig 1 : BepiColombo Interplanetary trajectory with the swingby dates (1) Moon 23 Jul 2012 (2) Earth 1 Nov 2013 (3) Venus1 27 Mar 2014 (4) Venus2 7 Nov 2014 (5) Mercury1 28 Jun 2016 (6) Mercury2 7 Aug 2016 Arrival 26 Nov 2016