NAVIGATION CONCEPTS FOR MULTI-REVOLUTION SEP TRANSFERS – T710-501GF – EXPRO+
20, aprilie 2018

ESA Open Invitation to Tender AO8887
Open Date: 13/04/2018
Closing Date: 04/06/2018 13:00:00

Status: ISSUED
Reference Nr.: 17.112.03
Prog. Ref.: Technology Developme
Budget Ref.: E/0901-01 – Technology Developme
Special Prov.: AT+BE+CH+CZ+DE+DK+EE+ES+FI+FR+GB+GR+HU+IE+IT+LU+NL+NO+PL+PT+RO+SE
Tender Type: C
Price Range: 200-500 KEURO
Products: Ground Segment / Mission Operations / Mission Control / Flight Dynamics Systems and Mission Analysis / Ground Segment / Mission Operations / Mission Control / Satellite and Ground Segment Simulators (e.g. simsat, eurosim, etc.)
Techology Domains: Flight Dynamics and GNSS / Flight Dynamics (FD) / Advanced Flight Dynamics Operations / Flight Dynamics and GNSS / Flight Dynamics (FD) / Advanced Flight Dynamics Processes and Tools
Establishment: ESOC
Directorate: Directorate of Operations
Department: Ground Systems Engineering Department
Division: Flight Dynamics Division
Contract Officer: Bednarek, Maren
Industrial Policy Measure: N/A – Not apply
Last Update Date: 16/04/2018
Update Reason: Modified the Tender Condition (English version)

Multi-revolution Solar Electric Propulsion (SEP) transfer from the low altitude launcher injection orbit to the final operational orbit is seriously considered or already base-lined for telecom (NeoSat, Electra, Alphabus-extension), Navigation (Galileo next generation) and Earth Observation satellites. With SMART-1 significant experience has been gained to carry out these operations by a fully ground-based approach using conventional radiometric measurements. Meanwhile the boundary conditions for such operations have changed considerably. Engine technology and characteristics have evolved. On-board GNSS based navigation has become standard. Developments are on-going to extend the use of GNSS to higher altitudes even up to GEO. Operations driving mission and spacecraft constraints (attitude control, eclipse handling, parallel payload operations) are different from SMART-1.Several promising operational conceptsshall be defined in terms of:- on-board equipment- navigation tasks to be performed on-board by the GNC system- navigation tasksto be performed on ground- tasks to be performed on-ground to support the on-board equipment and GNC system- Interface between the ground and on-board systemThe concepts shall cover the entire range between pure ground-based and full autonomous approaches. Thestudy shall pay special attention to hybrid concepts with an efficient sharing between ground and on-board functions. It shall include a concept where the orbit is determined and propagated on-board using GNSS and where the thrust direction profile and switching times are calculated optimally on-ground and up-linked to the spacecraft not in absolute times, but relative to the perigee passage time, which is known on-board. It is expected that the synchronization of the thrust with the perigee passage time allows to increase the interval of ground updates from 4 days for Smart-1 to several weeks. For fine targeting to the station position, a few free drift revolutions with small trim manoeuvres should be foreseen at the end.The following aspects of each concept shall be analysed:-navigation performance in terms of fuel usage and targeting accuracy- timeline of operations- ground operational load- on-board processing load- mission robustness- cost for on-board equipment and GNC algorithms- cost for ground system development and operationsPro’s and Con’s of the different concepts will be identified, quantified and compared to come up with recommendations for the future missions.

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