EChO is a candidate mission for the M3 launch opportunity, to be launched by 2024. EChO will be launched into a direct transfer orbit on a Soyuz-MT Fregat launch vehicle that will lift off from Europe's spaceport in Kourou, French Guiana.
The baseline for the EChO operational orbit is an eclipse-free, large-amplitude quasi-halo orbit around the night-side Sun-Earth libration point, L2. This will provide an environment that is benign with regard to radiation exposure and, critically for the photometric stability of EChO, and is also thermally stable. The proposed orbit has the added benefits of being eclipse-free (Earth and Moon) and provides instantaneous visibility of a large number of EChO targets at any one time.
With its very modest data volume, ground contact is expected to be needed for 2 hours, twice a week only.
EChO Science Operations
EChO is considered to be a survey-type mission, during which a core sample of targets that are selected pre-launch will be observed. A fraction of the total observing time is to be made available to the Community through open time. Proposals will be solicited through announcements of opportunity, and will be selected for execution by a time allocation committee.
The responsibilities and provision of the ground segment will be split between ESA and the nationally-funded Instrument Operations and Science Data Centre (IOSDC).
The ESA-provided ground segment elements include the Mission Operations Centre (MOC) to be located at the European Space Operations Centre (ESOC), the science operations centre (SOC) which will be located at the European Space Astronomy Centre (ESAC), and the ESA tracking station network.
The MOC will be responsible for the operations of the spacecraft and for the spacecraft health and safety. It will take overall responsibility for mission planning and upload of the platform and payload telecommands and reception of the downloaded telemetry data. The MOC will also be responsible for provision of the raw payload data, spacecraft housekeeping and auxiliary data.
The SOC will be responsible for the scientific mission planning, contact and delivery of the final instrument command timeline to the MOC, as well as the implementation and operation of the science data processing pipeline which will be provided by the IOSDC. The reconstruction of the EChO spacecraft pointing information is considered to be a critical task and will be an ESA responsibility taken care of by the SOC. The SOC will also develop, host and operate the EChO archive and provide the interface with the user community.
The IOSDC will be responsible for the long-term planning of the EChO core target sample. The IOSDC will provide software modules for the EChO data processing pipeline, as well as the calibration and technical data needed to generate the payload-specific mission data. It will also provide support to ESA for instrument maintenance and operations. The IOSDC will be run by the Instrument Consortium and will be distributed over a number of European institutes.