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Venus Express Ground Segment and Mission Operations Venus Express

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Venus Express Ground Segment and Mission Operations Venus Express Venuse Expresse n s s u s E x p r GrG oundo u r n d Segmente and g m e n t a n d Mission Operations Manfred Warhaut & Andrea Accomazzo ESA Directorate of Operations and Infrastructure, ESOC, Darmstadt, Germany SOC was responsible for developing the ground-segment facilities for both the ERosetta and Mars Express interplanetary missions. The high degree of commonality between those spacecraft and Venus Express, the twin spacecraft of Mars Express, has allowed large-scale re-use of ground-segment elements and the replication of the operations concepts for those spacecraft, resulting in significant cost and risk reductions. Operations Ground Segment Systems/Facilities The Venus Express Ground Segment provides the capabilities for monitoring and controlling the spacecraft and payload during all phases of the mission, as well as for the reception, archiving and distribution of the data gathered by the payload instruments. It therefore consists of (see figure): – a Ground Station and Communications Network – a Mission Operations Centre, and – a Science Operations Centre. The Ground Station and Communica- tions Network These elements are responsible for performing the telemetry, telecommand and tracking operations for Venus Express, using The Venus Express Ground Segment S/X-band frequencies. Tele-commands and telemetry are sent in either the S- or X- bands, with the possibility to transmit data-processing tasks essential for consolidated onward submittal to the simultaneously in both frequency bands, controlling the mission, as well as Mission Operations Centre (VMOC). The only one of which will be modulated. The S- spacecraft performance evaluation VSOC, which will be co-located with the band up/downlink is used only during the • the Data Disposition System, supporting VMOC during critical mission phases, will Launch and Early Operations Phase the acquisition and interim storage of make pre-processed scientific data and the (LEOP), in support of the Radio Science raw scientific data, to be accessible scientific data archive available to the Instrument (VeRa) campaigns, and in case together with raw housekeeping and scientific community through its Data of an emergency. The ground station used auxiliary data from the instrument Handling and Archive Service (DHAS). throughout all mission phases will be the Principal Investigators at remote The existing ESA/ESOC ground- new ESA 35 metre installation at Cebreros, locations, and to provide for production segment elements and facilities available near Madrid (Spain) (see accompanying of all data on a raw data medium for through the Rosetta and Mars Express article), complemented by the ESA New archiving purposes missions have been reused to the Norcia 35 metre station in Western Australia • the Mission Planning System, maximum extent possible, both in terms of to support the Venus Orbit Insertion and supporting command request handling hardware and software, for Venus Express. VeRa campaigns, and the Kourou 15 metre and the planning and scheduling of station during the LEOP. NASA DSN spacecraft/payload operations Flight Operations Concepts and Principles tracking support is provided as a back-up. • the Flight Dynamics System, supporting The Mission Operations Department at The Communications Network also all activities related to attitude and ESOC is responsible for the Venus Express provides the support services needed for orbit determination and prediction, mission operations preparation, planning accessing test data obtained during the preparation of slew and orbit and execution. All Venus Express spacecraft’s integration and test programme, manoeuvres, spacecraft dynamics Operations will be conducted by ESOC for the submittal of command requests to the evaluation and navigation in general according to procedures laid down in the ESOC/VMOC, for the retrieval of quick- • the Spacecraft Simulator, to support Venus Express Flight Operations Plan, a look mission products kept at ESOC, and procedure validation, operator training comprehensive document prepared by the also for supporting the electronic exchange and the simulation campaign before ESOC Venus Express Flight Control Team of scientifically processed data if required. each major phase of the mission (LEOP, based on Project/Industry deliverables VOI, etc.). (User Manual and Database), the Science The Mission Operations Centre Operations Plan, and Agreements with the The Venus Express Mission Operations The Science Operations Centre Principal Investigators. Centre (VMOC) located at ESOC in The Venus Express Science Operations Spacecraft operations during all active Darmstadt (Germany), includes: Centre (VSOC) supports the scientific mission phases – lasting about 2 years in • the Mission Control System, to support, mission planning and experiment total, with a possible extension of 1.5 years with both hardware and software, the command request preparation for – will be carried out following an 'off-line' 36 esa bulletin 124 - november 2005 www.esa.int Venus Express Ground Segment The Venus Express Mission Control Room at ESOC during the Launch and Early Operations Phase (LEOP) approach, with all activities being pre- Express Mission Operations Centre at spacecraft, with the primary responsibility planned and the appropiate telecommands ESOC and the spacecraft will not be for developing the payload operations being uplinked to the spacecraft for time- continuous and the periods of contact will strategy for the scientific mission resting tagged execution (via the onboard mission be primarily used for the pre-programming with the Venus Express Science Working timeline). The evaluation of telemetry data of autonomous operations functions on the Team (SWT). will also mainly take place off-line, with spacecraft, and for data collection for the possibility of quasi-real-time subsequent offline status assessment. The Mission Products intervention restricted to certain critical downlink will normally be configured such The mission products made available to the phases and cases of major contingencies. that most of the bandwidth is dedicated to Principal Investigators will include all There will be several communication- the dumping of onboard stored telemetry, spacecraft and experiment telemetry data blackout periods of up to two weeks with limited housekeeping and/or event and auxiliary data. Under nominal duration during the mission, due to the telemetry transmitted in real-time during conditions, all data acquired will be spacecraft-Earth-Sun geometry preventing the passes according to spacecraft available at the VMOC in engineering radio-frequency signal transmission. The monitoring requirements. format just 1 minute after their reception at round-trip communication time between the The Institutes who have developed the the ground station. r ground and the spacecraft will be up to scientific instruments are responsible for 30 minutes. Contact between the Venus defining their operation onboard the www.esa.int esa bulletin 124 - november 2005 37.
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