ESO is building the Phase Referenced Imaging and Microarcsecond Astronomy (PRIMA) facility for the Very Large Telescope Interferometer (VLTI) in Chile. PRIMA will enable interferometric imaging of very faint objects and high precision astrometry with both Unit (UT) and Auxiliary (AT) telescopes. The PRIMA facility consists of four major sub systems: Star Separators, Differential Delay Lines, Metrology and Fringe Sensor Units. TNO has developed the PRIMA Star Separator (STS) subsystems for both the UT and AT telescopes. The STS separates the light of two astronomical objects and feeds it into the long stroke delay line. The STS compensates for field rotation, stabilizes the beam tip tilt and adjust the lateral and axial alignment of the pupil. Chopping and/or counter-chopping on the science object or the guide star has also been implemented.

The Gaia mission 1 will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft 2

TNO TPD, in cooperation with Micromega-Dynamics, SRON, Dutch Space and CSL, has designed a compact breadboard cryogenic delay line for use in future space interferometry missions. The work is performed under ESA contract in preparation for the DARWIN mission. The breadboard (BB) delay line is representative of a future flight mechanism, with all materials and processes used being flight representative. The delay line has a single stage voice coil actuator for Optical Path Difference (OPD) control, driving a two-mirror cat's eye. Magnetic bearings provide frictionless and wear free operation with zero-hysteresis. Overall power consumption is below the ESA specification of 2.5 W. The power dissipated on the optical bench at 40 K is considerably less than the maximum allowable 25 mW. The BB delay line will be build in the second half of 2004. The manufacturing and assembly phase is followed by a comprehensive test program, including functional testing at 40 K in 2005. The tests will be carried out by Alcatel Space and SAGEIS-CSO.

The European Southern Observatory (ESO) has started technology development for their next generation optical telescope. Due to its ultra large collecting area, The European Extremely Large Telescope (E-ELT) will require a paradigm shift in telescope design to keep the overall program cost at an acceptable level. The E-ELT will feature a 42 meter segmented primary mirror and will make extensive use of active and adaptive optics. Each primary mirror segment will be supported by three actuators that control piston and tilt. TNO has developed a low cost nanopositioning actuator (PACT) for the primary mirror segments. The actuators will be tested by IAC and ESO, with support from TNO, under operational conditions in a Wind Evaluation Breadboard (WEB) at the Roque de Los Muchachos observatory in La Palma.

TNO has developed a compact BreadBoard (BB) cryogenic Optical Delay Line (ODL) for use in future space interferometry missions such as ESA's Darwin. The breadboard delay line is representative of a flight mechanism. The optical design is a two-mirror cat'seye. A single stage 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 Optical Path Difference (OPD) control. The verification program, including functional testing at 40 K, has been completed and showed compliance with all important requirements.