Determining the thermal extension under extreme conditions
Capacitive sensors from Micro-Epsilon detect the thermal extension of star sensor carriers. The measuring platform has been developed by KRP Mechatec in cooperation with Micro-Epsilon. Star sensors are optical measuring instruments based on CCD elements or other optical sensors. They are of utmost importance for space travel in order to determine the attitude and position control.
They must therefore provide micrometer-accurate measurement results in order to ensure exact position determination in space. Therefore, the supports on which star sensors are mounted must not be subjected to any thermal deformation. The behavior of the material used is therefore tested using high precision capacitive displacement sensors from Micro-Epsilon.
The carriers have a similar shape to a large »M«. One star sensor is mounted on the left, one on the right and another in the center. These sensors are tilted to the left or right. The sensor in the middle points vertically upwards. During the verification test, there are five capacitive sensors on each support, which detect in the X-, Y- and Z-axes a possible rotation of the platforms in the μrad range (for illustration: 1μrad corresponds to a displacement of 1μm at 1m lever arm). Tests of the measuring platform showed a stability of the rotation measurement at the reference surfaces of <0.1μrad/K.
Capacitive sensors are particularly well suited for measurement tasks that require highest precision. They also provide measurement values down to nanometer accuracy when exposed to extreme temperature fluctuations. The sensors are suitable for applications ranging from cryogenic temperatures or ultra-high vacuums, to dusty industrial environments or clean room applications. Capacitive sensors from Micro-Epsilon also provide long-term stability as there are no integrated components that could reduce the service life. Another strength is the combination variety. Each capacitive sensor can be operated with any Micro-Epsilon controller without requiring any complex calibration.