Gravity Gradient sensor technology for future planetary missions ESA ITT AO/1-3829/01/NL/ND Moons...
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Gravity Gradient sensor technology for future planetary missions ESA ITT AO/1-3829/01/NL/ND
Moons around Jupiter
Io Europa
ESTEC September 23 2005
University of Twente University of Nantes
R&D Programme
Programme for planetary exploration
• presented by Christophe Sotin
Programme for instrument development
• Gravity gradiometers based on MEMS and hybrid MEMS
orbiter
aerial vehicles/balloons (mapping smaller area)
• Laser cooled atom interferometry
• Multi sensor multi satellite systems
formation flying
MEMS-based GG systems
• important parametersmass, base line, temperature, quality factor, operating frequency
• design of prototype with sensitivity in range mE/√Hz
further development necessary
MEMS-based GG systems
First generation devices:• accelerometers and gradiometers with moderate sensitivity• fabrication of several devices with different spring approaches• material selection for electrodes• charge trapping studies by C-V and C-t measurements (pull-in
voltage, built-in voltage, temperature effects.• electronic readout, force feedback, integration on MEMS-device
Second generation devices:• Improvement of first generation devices with respect to sensitivity• Hybrid systems consisting of MEMS plus additional test mass• Study of floating systems• Study of modulation of spring constants• Inductive readout and the use of high Tc devices
MicroNED activities
• Several programmes within MicroNed:250 researchers: 9 knowledge institutes, 23 companiestotal budget M€ 28 (to be matched)
• Microsatellite programme MISAT
- development of a new generation of microsatellites, with formation flying abilities- payload development: gravity gradiometers, cooling- possible tests of instruments in space
• UT-development of some prototypes (1 PhD student)-further support necessary: Post Doc, technician, clean room costs-further ESA support would be great
Atom interferometry Conclusions
•Measurement is performed with the atom cloud in free falling, hence absolute value of gravity determines size, measuring time
•In space small sizes and long measuring time are possible
•Rb atoms are favorable with respect to cold collisions frequency shift
•A sensor for gravity gradient based on atom interferometry could achieve a sensitivity below 1 mE/√Hz using 10s interrogation time.
•Sizes: 10 cm diameter vacuum chambers, base line 1m
•Mass: some kg
Source: M. Kasevich, CAMOS 2002
http://www.atomchip.uni-hd.de/
Prospects for atom interferometry
Waveguides in atom chips
Multi sensor multi satellite systems
• Programme within Microned
- distance sensing (flight configuration)
- gravity sensing (accelerometers)
large base line systems
- magnetic sensing ( GMR, flux gates, high Tc devices)• UT
1 PhD student
• Additional support from ESA?
National Platform planetary research
• Established on October 29 in 2004
• Strengthen the relation between the Dutch potential for planetary research
institutions, universities, industries• Concentration
Astrophysics
Instruments (search for live, polarimeter, gravity gradiometers)
• Focussing on Mars