The Multiband Imaging Photometer for Spitzer (MIPS) provides long wavelength capability for the mission, in imaging bands at 24, 70, and 160 microns and measurements of spectral energy distributions between 52 and 100 microns at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point spread function and relatively large imaging fields of view, allowing for substantial advances in sensitivity, angular resolution, and efficiency of areal coverage compared with previous space far-infrared capabilities. The Si:As BIB 24 micron array has excellent photometric properties, and measurements with rms relative errors of 1% or better can be obtained. The two longer wavelength arrays use Ge:Ga detectors with poor photometric stability. However, the use of 1.) a scan mirror to modulate the signals rapidly on these arrays, 2.) a system of on-board stimulators used for a relative calibration approximately every two minutes, and 3.) specialized reduction software result in good photometry with these arrays also, with rms relative errors of less than 10%.

The Multiband Imaging Photometer for Spitzer (MIPS) provides long-wavelength capability for the mission in imaging bands at 24, 70, and 160 μm and measurements of spectral energy distributions between 52 and 100 μm at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point-spread function and relatively large imaging fields of view, allowing for substantial advances in sensitivity, angular resolution, and efficiency of areal coverage compared with previous space far-infrared capabilities. The 24 μm array has excellent photometric properties, and measurements with rms relative errors of about 1% can be obtained. The two longer-wavelength arrays use detectors with poor photometric stability, but a system of onboard stimulators used for relative calibration, combined with a unique data pipeline, produce good photometry with rms relative errors of less than 10%.

The GTO program for the MIPS team is concentrated in two areas. First, the evolution of planetary debris disks will be traced from their formation at less than one million years old, to the stable disks around old stars. To do so, we will make maps from 3 to 200 microns (in collaboration with the IRAC team) of regions where young stars are forming, to characterize thoroughly the circumstellar excess emission. We will include clusters representing a range of density and age. We will also observe a selection of isolated evolved stars in the MIPS photometric bands at 24, 70, and 160 microns. These observations will catalog the debris disk excesses as a function of stellar mass, age, binarity, and the presence of planetary companions. Second, we will explore the evolution of infrared galaxies and AGNs. This program has two components. In collaboration with both the IRAC and IRS teams, we will map at moderate depth 9 square degrees of sky, and in collaboration with IRAC will make deeper maps of about 2 square degrees. The latter regions have been selected to overlap with very deep xray surveys to aid in identification of AGNs and study of their evolution. We will extend the results of the deep maps by observations of 18 massive galaxy clusters in the redshift range 0.2 < z < 0.4. These clusters will image about 50 square arcmin of the background Universe, raising sources out of the confusion that will limit the sensitivity of the other deep surveys.

The Multiband Imaging Photometer for SIRTF (MIPS) will be one of the three instruments on the Space Infrared Telescope Facility (SIRTF). MIPS will produce images at 24 (128x128 pixels), 70 (32x32 pixels), and 160 (2x20 pixels) microns using Si:As (24 micron) and Ge:Ga (70 and 160 microns) based detectors. The reduction and calibration of the Ge:Ga images present special challenges due to the nature of the bulk photoconductive detectors. The observing strategy of MIPS has been specifically designed to make the reduction and calibration of the Ge:Ga images quite robust and is different from that employed by the Infrared Space Observatory (ISO). The observations are carried out in the fast not the slow time domain, i.e. sources do not stay on the same detector pixels between exposures (3, 4, or 10 seconds). In addition, all data are taken with a high degree of redundancy and a flat field is taken every 2 minutes. The repeatability of this flat field is better than 1%. Worst case source flux repeatability of 10-15% has also been demonstrated. The general outline of the Ge:Ga data reduction and calibration will be presented. This includes continuing characterization work in the laboratory with flight-like arrays which allows for the ongoing study of the behavior of Ge:Ga detectors.

Future space telescopes require primary mirrors that are much lighter than those currently being manufactured. They also must maintain optical tolerances while operating at cryogenic temperatures. We present a Mirror System Demonstrator for the Next Generation Space Telescope (NGST) that uses a thin glass facesheet with active control to achieve low mass and high surface quality. A 2-mm thick glass facesheet is controlled by miniature actuators and held together by a rigid carbon fiber frame. The 2-m diameter mirror system weighs only 13 kg/m2, including the glass, supports, actuators, support structure, and cabling. We present the status of the development and testing of this revolutionary mirror.

Traditional photoconductive detectors are used at 70 and 160 microns in the Multiband Imaging Photometer for SIRTF. These devices are highly sensitivity to cosmic rays and have complex response characteristics, all of which must be anticipated in the data reduction pipeline. The pipeline is being developed by a team at the SIRTF Science Center, where the detailed design and coding are carried out, and at Steward Observatory, where the high level algorithms are developed and detector tests are conducted to provide data for pipeline experiments. A number of innovations have been introduced. Burger's model is used to extrapolate to asymptotic values for the response of the detectors. This approach permits rapid fitting of the complexities in the detector response. Examples of successful and unsuccessful fits to the laboratory test data are shown.

We describe the design, construction, and performance of the 32x32 Ge:Ga imaging array being built at the University of Arizona for the Multiband Imaging Photometer for SIRTF (MIPS). The array will support a number of operational modes in the MIPS instrument including natural background-limited mapping at 70 mu m, super-resolution observations at 70 mu m. and spectral energy distribution measurements between 50 and 100 mu m. The array is constructed in a modular manner using eight 4x32 pixel building blocks. To meet the sensitivity and stability requirements, the array must have excellent photometric repeatability, low noise, and robustness to the effects of the ionizing radiation environment in space. Key elements in attaining this level of performance are the Ge:Ga detectors materials and the cryogenic CRC-696 readout electronics. We present laboratory data for a 16x32 prototype of the array, and describe the plans for the construction of the qualification and flight units.