The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultraviolet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star stracker stellar compasses (star tracker camera-I-stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 FPA and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 mv, providing rms pointing accuracy of better than 100 p a d pitch and yaw and 450 p a d roll. A description of this lightweight , low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission's primary objective for flight qualifying the sensors for future Department of Defense fights.

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July 20, 1998This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, this preprint is made available with the understanding that it will not be cited or reproduced without the permission of the author. PREPRINTThis paper was prepared for submittal to the DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. Abstract. This paper summarizes the work at Lawrence Livermore National Laboratory in the development, integration and testing of the critical enabling technologies needed for the realization of agile micro-satellites (or MicroSats). Our objective is to develop autonomous, agile MicroSats weighing between 20 to 40 kilograms, with at least 300 m/s of Dv, that are capable of performing precision maneuvers in space, including satellite rendezvous, inspection, proximity operations, docking, and servicing missions. The MicroSat carries on-board a host of light-weight sensors and actuators, inertial navigation instruments, and advanced avionics. The avionics architecture is based on the CompactPCI bus and PowerPC processor family. This modular design leverages commercial-off-the-shelf technologies, allowing early integration and testing. The CompactPCI bus is a high-performance, processor independent I/O bus that minimizes the effects of future processor upgrades. PowerPCs are powerful RISC processors with significant inherent radiation tolerance. The MicroSat software development environment uses the space flight proven VxWorks, a commonly used, well tested, real-time operating system that provides a rapid development environment for integration of new software modules. The MicroSat is a 3-axis stabilized vehicle which uses cold gas N 2 for ACS and a novel pressure-fed, non-toxic, monopropellant hydrogen peroxide propulsion system for maneuvering. SSC98-V-1

Lawrence Livermore National Laboratory developed a space-qualified High Resolution (HiRes) imaging LIDAR (LIght Detection And Ranging) system for use on the DoD Clementine mission. The Clementine mission provided more than 1.7 million images of the moon, earth, and stars, including the first ever complete systematic surface mapping of the moon from the ultraviolet to near-infrared spectral regions. This article describes the Clementine HiResLIDAR system, discusses design goals and preliminary estimates of on-orbit performance, and summarizes lessons learned in building and using the sensor. The LIDAR receiver system consists of a High Resolution (HiRes) imaging channel which incorporates an intensified multi-spectral visible camera combined with a Laser ranging channel which uses an avalanche photo-diode for laser pulse detection and timing. The receiver was bore sighted to a lightweight McDonnell-Douglas diode-pumped NdYAG laser transmitter that emmitted 1.06 pm wavelength pulses of 200 mJ/pulse and 10 ns pulse-width. The LIDAR receiver uses a common F/9.5 Cassegrain telescope assembly. The optical path of the telescope is split using a color-separating beamsplitter. The imaging channel incorporates a filter wheel assembly which spectrally selects the light which is imaged onto a custom 12 mm gated image intensifier fiber-optically-coupled into a 384 x 276 pixel frame transfer CCD FPA. The image intensifier was spectrally sensitive over the 0.4 to 0.8 pm wavelength region. The six-position filter wheel contained 4 narrow spectral filters, one broadband and one blocking filter. At periselene (400 km) the HiResLIDAR imaged a 2.8 km swath width at 20meter resolution. The LIDAR function detected differential signal return with a 40-meter range accuracy, with a maximum range capability of 640 km, limited by the bit counter in the range return counting clock. The Imagery from the HiRes is most useful for smaller scale topography studies, while the LIDAR data is used for global terrain and inferred gravity maps.