Influence of the Mercury gravity field on the orbit insertion strategy of BepiColombo

Abstract

In this paper the Mercury orbit insertion (MOI) in January 2022 of the ESA mission BepiColombo consisting of 15 manoeuvres is optimised. To maximise the mass in the target orbit, the gravity losses of the 15 burns are minimised by distributing the burns as evenly as possible. However, severe Sun aspect angle constraints make the optimisation problem difficult to solve. The NLP-solver SNOPT is used for the optimisation.The uncertainty in Mercury's gravity field is still high, such that its influence on the MOI was evaluated in several simulations of Mercury's gravity field. Since the target orbital parameters are still discussed their influence on the MOI ΔV-budget is investigated. The results indicate that the reference case was selected adequately. Since changes in arrival date, scientific orbit, instruments and strategies until BepiColombo's launch in 2015 are possible, this paper covers a wide range of possible future arrival options.