Evaluation and test of different gear concepts for Ka-band Antenna Pointing Mechanisms

The goal of this work was to (1) evaluate different gear concept for spaceflight application with minimum backlash, (2) design a test setup to test the most promising concepts, and (3) conduct preliminary validation tests. The evaluation focused on the primary possibilities to influence the behavior of gear performance: variation of material and variation of geometry. The synthetic materials PEEK and Vespel were evaluated with respect to vacuum compatibility, wear and strength. Both materials performed promising for space application. To investigate the influence of gear geometry, a profile shift of the gears and a reduction of the tooth height were analyzed and tested. The new gear concepts were investigated in a specially design test setup. It allows the measurement of backlash with an adjustable distance of the two gear axes. The test setup also allows for the testing of friction and wear, which is not part of the presented work. The design of the test bed also allows testing in thermal-vacuum environment. First tests were conducted to verify the functionality of the test setup. Preliminary measurements with two different gear geometries were performed. A larger follow-on study will then test various gear design concepts in thermal-vacuum conditions and has the goal to compare the design solutions regarding application in high accuracy space mechanisms.