The development of a breadboard Cryogenic Optical Delay Line for DARWIN

TNO has developed a compact BreadBoard (BB) cryogenic Optical Delay Line (ODL) for use in future space interferometry missions such as ESA's Darwin and NASA's TPF-I. The breadboard delay line is representative of a flight mechanism. The optical design is a two-mirror cat's-eye. A linear guiding system based on magnetic bearings provides frictionless and wear free operation with zero hysteresis. The delay line has a voice coil actuator for single stage Optical Path Difference (OPD) control. The verification program, including functional testing at 40K, has been completed succesfully.