ESA GNC Conference Papers Repository

Brand-new star trackers of Geofizika-Cosmos. From 348K success to new challenges
V. Knyazev
Presented at:
Salzburg 2017
Full paper:

The first 348K (multi-headed star tracker) was sent to space in September 2014 on the spacecraft of JSC ISS Reshetnev. Planned technical decisions including light sensitivity, equal accurate attitude, methods of compilation of the star catalogue, design and software decisions, interference immunity, space factors and sun activity tolerance were approved during in-flight test. Evaluation of key characteristics were made on telemetry data: random attitude error, recovery from lost in space, determination of orientation, baffle Sun exclusion angle. Currently serial production of flight models already in process: already delivered to customers 6 devices 348K (equal to 22 autonomous STR), and more than 10 devises 348K (equal to 40 STR) already ordered. Today two new devices ordered by Roscosmos for future spacecrafts are developing in JSC 'NPP 'Geofizika-Cosmos': high class star tracker and compact star tracker. Both devices being developed (are designed ??? developed) for using on GEO - 16 years, HEO - 12 years, GLONASS - 10 years, and also low orbits up to 10 years. Both devices are monoblocks. Ideas successfully implemented in 348K have received further development in new devices. High accuracy class device 361K represents deep modernization of 348K optical head. 361K is an autonomous star tracker with random error 0,8 arc.sec. and total error less than 6 ang.sec (EOL conditions). Its design and improved internal optical reference (348K heritage) provide high stability of measurements. Such kind of star tracker can be used on spacecraft for Earth's remote sensing and scientific missions for which it is essential to provide high accuracy of guidance. The device can be used stand alone as well as multi-headed star tracker with several OH with EU adopted from 348K. Autonomous compact star tracker 362K has accuracy characteristics enough for biggest part of communication, navigation and telecommunication spacecrafts. The most important characteristic is low mass, less than 1kg including baffle with SEA 30 degrees. Also extended angular rates range and angular acceleration are provided (up to 5 deg/s and up to 0.5deg/sec2 respectively). Russian CMOS rad-hard sensor 'Mask-2' was developed and produced for both new star trackers. At the moment this sensor is being ground qualified. Photosensitive characteristics of 'Mask-2' allow to increase light sensitivity for more than 5 times and provide data update rate at 10Hz. Important object resolving during developing of both devices is to support technological independence. All the materials and components are produced by Russian industry. It allows to optimize the price of devices, terms of delivery and logistics of orders. The beginning of in-flight test is planned for 2018. Engineering units were manufactured in 2016 and test campaign (ground tests) started. Some flight results of 348K, as well as new star trackers details are given in the full paper.