BepiColombo MPO SSMM and Data Downlink Modelling for Science Operations Analysis

Abstract

BepiColombo is an interdisciplinary cornerstone mission to planet Mercury. It is a joint mission between ESA and JAXA consisting of 2 complementary spacecraft, the ESA Mercury Planetary Orbiter (MPO) and the JAXA Mercury Magnetospheric Orbiter (MMO). The two spacecraft will be independently operated and controlled from the MPO Operations Ground Segment (OGS) located at the European Space Operations Centre (ESOC) and the MMO Operations Centre at ISAS/JAXA Sagamihara Space Operations Centre (SSOC). The science operations for MMO will be prepared by the MMO Science Operations Centre at SSOC while the MPO operations by the MPO Science Ground Segment (SGS), located at the European Space Astronomy Centre (ESAC) in Madrid, Spain. The BepiColombo MPO Science Ground Segment (SGS) combines the functionalities of a Science Operations Centre, covering the science operation planning and generation of consolidated payload command requests, and the science data handling and archiving tasks. BepiColombo’s MPO scientific payload comprises 11 instruments that will investigate the Mercury planet interior, surface composition and morphology, the intrinsic magnetic field and the composition of the exosphere and the coupling between all of these fields. The BepiColombo MPO has a large on board SSMM (Solid State Mass Memory) in order to store engineering and science data with a total capacity of 384 Gbit. The telemetry science data packets are stored in the SSMM packet stores based on Process Identifiers (PIDs). The instruments have been specified to generate lowand/or high-priority science data with different PIDs, such that this data can be stored in different packet stores. The BepiColombo MPO has two different radio frequency bands available for data return. The X-band channel is predictable in terms of planned data downlink and will be therefore used to return near real-time data needed on ground to check the spacecraft status/health and highpriority science data. In addition, a Ka-band downlink channel is available, where due to weather uncertainties larger data downlink latencies might arise. Thus, it is foreseen to return low-priority science data using the Kaband via file transfer with automatic retransmission of any lost packets. BepiColombo MPO has several downlink mechanisms in order to get the science data in an efficient way back to ground that combine the large