BepiColombo, ESA's Mercury Cornerstone mission (original) (raw)

2001, Planetary and Space Science

The paper presents the results of the deÿnition studies performed for the European Space Agency (ESA) on system architectures and 7 enabling technologies for "BepiColombo", a Cornerstone class mission to be launched in the 2007-2009 time frame. The scientiÿc mission comprises 1-year observations by a Mercury Planetary Orbiter (MPO), dedicated to remote sensing, and a Mercury Magnetospheric Orbiter 9 (MMO), dedicated to particles and ÿelds, plus short-duration in situ analysis by a Mercury surface element (MSE). A exible approach to the programme has been developed, comprising two alternative launch scenarios. In the ÿrst option (2009), the 2500-kg class satellite 11 composite, including two propulsion modules and three scientiÿc modules, is launched by an Ariane-5. The trajectory design is based on Venus and Mercury gravity assists plus the thrust provided by a Solar Electric Propulsion Module (SEPM), that is jettisoned before 13 being captured into Mercury orbit. Capture and orbit insertion, executed by successive manoeuvres of a Chemical Propulsion Module (CPM), occur less than 2:5 yr after launch. In the second scenario, the mission is split into two launches of a small launch vehicle. Two 15 1200-kg class composites are launched either in the same one-month window or at an interval of 1:6 yr. One composite comprises the SEPM, CPM, MMO and MSE and the other comprises duplicate SEPM+CPM and the MPO. The trajectory design follows the same 17 principles as the Ariane-5 mission, with the SEPM thrust reduced by half and cruise duration ranging between 2.3 and 3:5 yr. Whatever be the implementation, the mission is expected to return about 1700 Gbit of scientiÿc data during the one-year observation phase. The 19 crucial aspects of the spacecraft design are associated with, and constrained by, the high-temperature and high-radiation environment. Basic feasibility has been demonstrated by an extensive design and analysis exercise, and the focus of the programme has now moved to 21 a 3-year preparatory programme dedicated for developing the enabling technologies.