Metrology & AIVT
To support and complement the formulation of various space missions, we develop and validate experimentally selected key technologies in the wide field of optical metrology, which is indispensable for high precision measurements in space. All these activities are carried out in collaboration with EADS-Astrium in Friedrichshafen as well as DLR-RY Bremen and partially with the HTWG Konstanz and the Humboldt-University Berlin.
Several space missions were proposed that should perform measurements with an unprecedented accuracy. For example, the Laser Interferometer Space Antenna (LISA/eLISA/NGO) is a mission to detect gravitational waves and consists of three satellites. To directly observe the gravitational waves, the measurement of the distance between the freely falling test masses inside the satellites (approximately 5 106 km) must be sensitive to 20 picometer variations (10-12m).
GRACE Follow ON (GRACE-FO), a mission to map Earth's gravitational field precisely, consists of two spacecrafts. The relative distance between the freely falling test masses inside the two satellites (approximately 200km) has to be tracked on a nanometer (10-9m) scale.
The Space-Time Asymmetry Research project (STAR) intends to search for violations of the Lorentz invariance using a Michelson-Morley and a Kennedy-Thorndike experiment. To achieve the proposed sensitivity a clock line width of 10-16-10-18 is indispensable.
All the aforementioned space missions require highly stable frequency and distance metrology instruments that are not only realizing the sensitivity of the ambitious scientific goals but also withstand the conditions during the launch of the satellites (shocks, vibration, thermal) and in space (vacuum, radiation, thermal). In the space technology division of ZARM, we develop optical instruments meeting these requirements together with the DLR-RY, EADS Astrium Friedrichshafen, the HTWG-Konstanz and the Humboldt-University Berlin. Amongst these are ultra precise clocks (Iodine frequency standard) and interferometers.
The ever increasing accuracy of measurements of fundamental physics demands also the development of new materials and instruments. For example, the thermal expansion of all materials must be reduced significantly. On the other hand, the validation of the properties of the new materials makes it necessary to devise test facilities. Similarly, the development of μN-thrusters requires a test scenarios to characterize its properties precisely. For both examples and other new technologies, very accurate measurements are mandatory. These are developed in the space technology division of ZARM as well.
We also participate and devise future space missions to test fundamental physics. Currently, the STE-QUEST mission is studied in the scope of the third cosmic vision program M3 of ESA.