The Infrared Telescope Technology Testbed (ITTT) is being developed by Hughes Danbury Optical Systems (HDOS) for the Jet Propulsion Laboratory as part of the NASA OSAT Telescope Technology Program. The ITTT will demonstrate critical lightweight infrared optical systems technologies to enable future NASA missions including SIRTF and commercial applications including earth observation and remote sensing systems, satellite-to-satellite communications systems, aircraft-borne LIDAR systems for detection of wind shear and military surveillance and early warning systems.
In June, 1994, JPL issued a Request for Proposal inviting U.S. industry and academia to propose concepts for technology development and demonstration leading to a cryogenic infrared telescope with twice the collecting area, half the mass, and one third the diffraction limited wavelength of the IRAS telescope. In August, 1994, HDOS was selected from among three competing teams on the basis of their technical proposal and was on contract September 1, 1994.
The winning HDOS design was for an essentially all beryllium, 85cm clear aperture telescope with a single arch lightweight primary mirror achieving diffraction limited performance at 5 microns. Advanced design concepts including use of a central metering tower for baffling and secondary mirror support led to an ultralightweight 30 kg design. Advanced beryllium materials and processing techniques developed at Brush Wellman as part of the Telescope Technology program will used in manufacturing the ITTT to achieve thermal and dimensional stability of the hardware. The monomaterial design and simple mechanical and optical interfaces simplify the assembly, integration and alignment of the ITTT and lead to highly predictable performance at the operational temperature of 5.5 kelvins.
The primary mirror assembly was delivered to JPL in July of 1995 and is being readied for cryogenic optical testing. Later in 1995, the remainder of the testbed will be delivered, assembled, aligned and integrated in the JPL cryogenic optical test facility. The fully integrated testbed will undergo cryogenic optical and random vibration testing in late 1995 and early 1996. Following performance verification testing, the testbed can be used for validation of focal plane instrument module performance and investigation of observatory system trades related to thermal management, pointing, cryogenic mechanisms, etc.

Information provided by: http://ranier.oact.hq.nasa.gov