Multi-headed star tracker 348K. Final in-earth validation results

This paper is about multi-headed star tracker 348K, which was developed by JSC “SPE “Geofizika-Cosmos” in 2013. Concept, design and key features are described. The design features are to provide a monolithic body of the lens, which implements both the seating surfaces. Moreover, in the device 348K a special system - channel geometric standard, which is high stability optical system and forms on the APS-based camera six images for self-supporting estimation and compensation of systematic errors in the determination of orientation caused by the thermo-mechanical effect is employed. Also test program during the manufacturing and in-Earth validation as well as some tests details are presented. In tests, the star tracker 348K was first introduced check errors in a movable base. Testing the effect of protons with energies of 50, 100 and 200 MeV at different angles of incidence on the APS-based camera conducted to quantitatively and qualitatively assess the impact of the incident protons on the image. According to the analysis of emerging sustainable defective pixels on APS-based camera, it was determined that the greatest increase in defect occurs when the energy is 200 MeV. During the full-scale tests measuring the time of construction of the initial orientatio was conducted. According to the results of full-scale tests random error components determination of the orientation of one of the optical head and two optical head for 15 minutes of work were evaluated. The purpose of full-scale tests was to confirm the unit validation of availability on the real star, rather validation of the chosen algorithmic solutions, and methods to assurance of accuracy and sensitivity. The whole test program during the manufacturing and in-Earth validation was successful, the results of all tests are positive. According to the test results the final report on the ground-experimental testing was released. After the ground tests of the first flight unit 348K on board the spacecraft was obtained on admission to the conclusion of flight testing, the beginning of which is expected in 2014.