Microscope (MICRO Satellite à traînée Compensée pour l'Observation du Principe d'Equivalence) is a part of the micro-satellite line of CNES (Centre National d'Études Spatiales, France). The objective of the mission is to test the Principle of Equivalence with an accuracy of 10-15, or three orders of magnitude better than the accuracy that can be achieved with ground-based experiments like pendulum or torsion-balance experiments.
This accuracy will be achieved by means of long integration time with extremely sensitive capacitive acceleration sensors developed by ONERA (Office National d'Etudes et de Recherches Aérospatiales, Châtillon, France).
MICROSCOPE is scheduled for launch in 2016. The planned mission duration is at least 18 months.
This mission will be the first opportunity which Europe has had to qualify the technologies for drag-free satellites. Testing such a satellite is essential for future missions related to fundamental physics (Detection of gravitational waves, LISA and OMEGA), astrophysical interferometry (GAIA, DARWIN), and precise gravitational field determination.
MICROSCOPE actions at ZARM
Hardware tests in microgravity
ZARM is responsible for the test and verification of the accelerometers developed at ONERA (Chatillon, France) under "zero-g conditions". In particular, numerous experiments on the drop tower are performed to demonstrate sensor performance and structure characteristics. For this purpose a new freeflyer technology has been developed and tested. The freeflyer platform shows an improved µg-quality compared to the standard drop capsules used at ZARM by orders of magnitude. The free fall tests of the MICROSCOPE hardware at the drop tower are essential for the success of the whole mission.
High performance satellite dynamics simulation
The ZARM-MICROSCOPE group, which is a member of the science team, currently prepares the data evaluation process. Therefore, a comprehensive simulation of the real system including the science signal and all error sources is built for the development and testing of data reduction and data analysis algorithms to extract the EP violation signal. Currently, the ZARM/DLR High Performance satellite dynamics Simulator HPS, a tool to support mission modelling, is adapted for the MICROSCOPE mission in order to simulate test mass and satellite dynamics. Models of environmental disturbances like solar radiation pressure are considered, also. Additionally, detailed modelling of the on-board capacitive sensors is done.
The result of this work is the base for the mission and post-mission data analysis that will be performed at ZARM in close cooperation to the french partner institutes.
The contribution of ZARM is supported and funded by the German Space Agency DLR under grant number 50OY0801.
Dipl.-Ing. Stefanie Bremer
Dr. Meike List
Dipl.-Phys. Hanns Selig
Dr.-Ing. Benny Rievers
- Touboul P., Rodrigues M. "The MICROSCOPE mission'', Class. Quantum Grav. 18 (2001) 2487-98
- Touboul P., 2001, "Space Accelerometers: Present Status" in: Gyros, Clocks, Interferometers...: Testing Relativistic Gravity in Space, Springer (2001) 273-291.
- Bremer S., Selig H., List M., Dittus H.: "Modelling and simulation of the space mission MICROSCOPE", Acta Astronautica 68, 28-33 (2011)