MICROSCOPE is a CNES-ESA-ONERA-CNRS-OCA-DLR-ZARM joint mission, based on a CNES microsatellite from the Myriade product line. It has been launched on April 25th 2016, with the scientific objective to proof-test the Equivalence Principle with an unprecedented accuracy of 10-15. MICROSCOPE uses the Earth as gravitational source. It records the relative movement of two cylinders, each one being made of a different material. If the theory applies, it is expected that the two different masses, being subject to the same gravitational accelerations, would follow the exact same free-fall movement. This experiment relies on the protective cocoon of the spacecraft which frees the instruments T-SAGE of the disruptive forces: the non-gravitational forces acting on the satellite are compensated using cold gas micro-propellers (CGPS); this unique feature is known as "drag compensation" or "drag-free flight". The attitude guidance is based on star tracker (SST) measurements (fitted with two optical heads) and acceleration measurements of the payload instrument itself. The paper will address the challenges the MICROSCOPE teams faced while bringing the spacecraft up to its full operational capability in December 2016. Some serious anomalies had to be tackled by applying workarounds both to the on-board software and the ground-based operations, resulting in a set of brand-new operational constraints. Indeed, after a good injection and very good start of the platform sub-systems, the various satellite modes were tested: the coarse guidance mode (MNOG), the fine guidance mode (MNOF which uses the CGPS and SST) and the drag-free mode (6-axis control on attitude and acceleration with hybridization of the instrument measurements). During this in-orbit test campaign, some serious anomalies occurred, first of all on the SST, then on the CGPS and T-SAGE. The teams took corrective measures (by uploading patches for the onboard software and its configuration) and engineered operational workarounds on ground (modifications of operational procedures and adaptation of the routine mission definition). Time was a concern since the mission lifetime was driven by the remaining amount of the gas on board. We shall emphasize the following points which were implemented from the beginning of the С phase and which were key to success: 1) the involvement of a team federating spacecraft experts, specialists with an extensive experience of space operations, members of the project development team and science experts; 2) the operational concept which was collectively designed before the system tests phase ; 3) several long duration tests (i.e. 6 tests from 2 to 3 weeks each), run during the operational qualification, involving almost all the components of the ground segment: the command control center (CCC), the "mission programming and performance expertise" center (CECT) and the scientific mission center (CMSM) where final products are built. Only the ground station network was not in the perimeter of these tests. Moreover, we also chose very early to set up a ground test platform consisting of a test-dedicated CCC and a test-dedicated CECT which were qualified by one of the long-duration system test. As a result, this allowed to accommodate the development of workaround solutions and the validation of onboard software, while keeping running in parallel the in-orbit test operations. Our operational team, initially manned with only 2 engineers responsible for satellite's operations, has been reinforced very soon. Although MICROSCOPE is a microsatellite of the MYRIADE family for which we had an extensive set of existing operational procedures inherited from previous missions (such as DEMETER, PARASOL, PICARD, ESSAIM), from the very beginning of the system test phase, we noticed that most of these procedures (80%) needed adaptation to cope with MICROSCOPE specificities. We have had to re-write them because the operations on MICROSCOPE were very dependent on the new propulsion system and the T-SAGE instrument. This team, ultimately manned with 4 engineers, allowed us to cope with a constrained and challenging in-orbit test campaign. This manning is still on duty for the current routine phase. The paper will also address our new experience on the operational documentation, which has been written for the very first time using the dokuwiki technology. In this collaborative reference, the payload and platform experts have provided inputs on all operational constraints, which have been translated into operational procedures for routine and anomaly handling scenarios, dealing with the spacecraft management, flight dynamics and mission management. The principle was to draft pages related to the sequence under test, to update them in real time during the tests and finally to have them validated by the experts in a very short and reactive loop. This short loop has proven its efficiency especially against the very constrained test schedule, avoiding the time-consuming standard paper documentation review, for instance. This wiki experience, started from scratch, paved with issues and success, is now a valuable knowledge shared outside the project with other operational teams, giving new perspective on the way to drive operations for the CNES space missions to come.
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