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Very large telescopes will be needed for the future of space science, space laser-com, and other interstellar or interplanetary applications. However, as telescopes’ diameters increase, their weight and cost increase dramatically. An approximation for ground-based observatories is that their cost increases to the power of 2.7 of its diameter [SAO, Special Report #385 (1979), p. 9]. Large space-based telescopes become limited by the rocket size and power. Multiple telescopes are also needed for very long baseline interferometry (VLBI), which further increases cost. A solution to overcome these issues is the use of inflatable telescopes. A thin mirror material clearly has much lower mass; however, controlling its surface error or wavefront can be a challenge. Intensity interferometry is an imaging method that has a much looser sensitivity to wavefront error (WFE), and thus is an ideal match for very large inflatable telescopes. A spherical inflatable mirror is the most practical; however, it suffers from spherical aberration. This paper presents new optical designs and simulations for intensity interferometry in support of large inflatable spherical telescopes. The optical system design includes a novel five-mirror off-axis, free-form, spherical aberration corrector. The system design shown is a 10 m diameter f/1 spherical primary mirror with 1.2 arcmin (0.02°) field of view (FOV). MATLAB simulations of intensity interferometry combine signal with noise and WFE. Visibility-based VLBI image simulations are shown based on various telescope arrays. Simulations show that with a 1 GHz detector, a 1 cm RMS WFE is tolerable. So the challenge of the optical design is then more about gathering and concentrating the light down to a reasonable size detector. Further simulations of signal combined with noise indicate that the signal rate must be about 100 times higher than the noise rate for an adequate intensity interferometry measurement. Visibility-based image simulations reveal that many telescopes (5–20 per axis) are needed in a 2D array out to the first visibility minimum to adequately resolve unknown features of a distant object.

Two disruptive space telescope concepts are being designed and developed at the University of Arizona; these are the 20-meter OASIS (Orbiting Astronomical Satellite for Investigating Stellar Systems) and 8.5-meter Nautilus. OASIS combines break-through inflatable aperture and adaptive optics techniques to realize the dream of a 20+ meter class spaceborne terahertz/far-infrared telescope. In the Nautilus visible/near-infrared telescope concept, conventional primary mirrors are replaced by an ~8.5-meter MODE (Multi-order diffractive engineered) lens with 10 times lower areal density and up to 100 times lower mis-alignment sensitivity over traditional systems, enabling large-diameter optical space telescopes. The OASIS and Nautilus concepts have the potential to greatly reduce mission costs and risks compared to the current state of the art.

The Mars Surveyor Spacecraft's Robotic Arm Camera (RAC) is a CCD imager designed to enhance the capability of studyingboth trenched areas and material collected by the craft's Robotic Arm. Because of the wide range of object distances/imagescales desired, an active focus mechanism will be used, capable of imaging from a magnification of 1 : 1 to infinity focus, witha maximum resolution of 23 microns/pixel for Mars surface material samples in the mouth of the scoop. This paper willdiscuss the optomechanical design of the optics, mechanism, and actuator, operational scenarios for the most efficientcollection of the necessary images, and algorithms for selection of images to be returned to earth.Keywords:Optomechanical, camera, autofocus, instrument, Mars 1. INTRODUCTION The Mars Volatiles and Climate Surveyor (MVACS) instrument package to be flown on the Mars SurveyorSpacecraft scheduled for launch in January, 1999, includes a Robotic Arm for collecting and delivering samples to a thermalanalysis instrument. The Robotic Arm Camera, to be mounted at the wrist, will be capable of imaging the contents of thescoop, the interior of the trench and surrounding areas, and even the horizon. Figure 1 .

The use of subwavelength near-field apertures opens the possibility of optical dish data density increases in excess of 4 orders of magnitude.

A projection system is described which can simulate emissions from flares, muzzleflashes, shellbursts, and other emissive agents which may degrade the performance of electrooptical systems in the 0.5–15 μm spectral range. The simulation capability obtained will allow the apparent radiance and temporal characteristics of muzzleflashes and shellbursts to be mimicked at simulated ranges as close as 23 m within the Electro-Optical Test Facility. This demonstrates that tests of electro-optical system performance in the presence of interferers can be performed under laboratory conditions with higher repeatability and lower cost than field tests.