<title>Star tracker stellar compass for the Clementine mission</title>

Abstract

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.

Clementine Observations of the Zodiacal Light and the Dust Content of the Inner Solar System

“…1, and a more detailed description of the instrumentation may be found in Lewis et al (1991) and Kordas et al (1995). The camera's principle components are a spherical lens, a fiber optic, and a CCD detector.…”

“…4A). Nonetheless, the time to transfer the contents of one pixel to the next, 94.4 µsec (Kordas et al 1995), is a fixed quantity, so the intensity of each column's streak can be inferred and removed from the raw data itself using the destreaking algorithm given in . However this algorithm fails whenever a CCD column contains one or more saturated pixels.…”

<title>UV/visible camera for the Clementine mission</title>

“…[1]) is the chassis and core electronic unit of this camera. It is also the basic building block of the Clementine star tracker and Clementine HiRes cameras.…”

Design of a novel star tracker optical system

“…A spacecraft which carries a star tracker will use the data from the star tracker to determine its orientation. For sampling purposes [1][2][3][4][5][6], the image plane in the tracker is defocused slightly so that the spot image will spread over several pixels of the CCD sensor. This arrangement makes it possible to determine the position of stars with an accuracy that is a small fraction of one pixel.…”