Ball Aerospace is currently under contract to Marshall Space Flight Center (MSFC) in Huntsville, AL to design, build, and test a state-of-the-art lightweight beryllium mirror for cryogenic space applications, the Next Generation Space Telescope (NGST) Sub-scale Beryllium Mirror Demonstrator (SBMD). The mirror is manufactured from spherical powder beryllium and optimized for cryogenic use. This 0.53-meter diameter lightweight mirror (<12 kg/m2) has been tested at MSFC at ambient and cryogenic temperatures down to 23K, cryofigured for optimal performance at 35K, and subsequently retested at cryogenic temperatures. In addition, Ball has a separate contract with MSFC for an Advanced Mirror System Demonstrator (AMSD) to fabricate and test an ultra-lightweight mirror system which extends the semi-rigid SBMD mirror design to a 1.4-meter point-to-point beryllium hexagon mirror, flexures, rigid body and radius of curvature actuators, and reaction structure. This paper will describe the SBMD mirror performance and its cryogenic testing and present an overview of the AMSD semi-rigid beryllium mirror.
The High Resolution Imaging Science Experiment (HiRISE) camera will be launched in August 2005 onboard NASA's Mars Reconnaissance Orbiter (MRO) spacecraft. HiRISE supports the MRO Mission objectives through targeted imaging of nadir and off-nadir sites with high resolution and high signal to noise ratio [a]. The camera employs a 50 cm, f/24 all-reflective optical system and a time delay and integration (TDI) detector assembly to map the surface of Mars from an orbital altitude of ~ 300 km. The ground resolution of HiRISE will be < 1 meter with a broadband red channel that can image a 6 x 12 km region of Mars into a 20K x 40K pixel image. HiRISE will image the surface of Mars at three different color bands from 0.4 to 1.0 micrometers. In this paper the HiRISE mission and its camera optical design will be presented. Alignment and assembly techniques and test results will show that the HiRISE telescope's on-orbit wave front requirement of < 0.071 wave RMS (@633nm) will be met . The HiRISE cross track field is 1.14 degrees with IFOV 1.0 µ-radians.
An effort has been in place at Ball Aerospace & Technologies Corp. (BATC) for over three years to develop a mechanism for precise positioning of optical elements for such applications as the Next Generation Space Telescope (NGST). It is desired for such a mechanism to be of low mass, to have nanometer-level positioning capability over a comparatively large range of travel, to be both ambient and cryogenically capable, and to have high strength and stiffness capabilities. The development effort has resulted in a simple 288-gram mechanism that meets these requirements, and does so with a single stepper motor and a simple control system. Performance has been verified at both ambient and cryogenic temperatures, and the mechanism design is currently being implemented on BATC's Advanced Mirror System Demonstrator program (AMSD). The current design achieves steps of less than 10 nanometers per step over more than 20mm of travel. We will present an overview of the capabilities of the mechanism, as well as a discussion of the test results achieved to date. Test results will include both ambient and cryogenic performance, hysteresis and stiffness measurement, as well as verification of single-stepping capability.
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