Functional verification and performance tests of an ultra-low shock non-explosive actuator for hold-down and release mechanisms for space applications

Abstract

This paper addresses the functional verification and performance assessment of an ultra-low shock non-explosive actuator appropriate to space applications of hold-down and release mechanisms. To demonstrate that the design implementation and manufacturing methods have resulted in an engineering model conforming to the set of functional, performance and environmental requirements specified, a space qualification test campaign is typically required. To ensure the readiness of the engineering model and the adequacy of the mechanical and electrical ground support equipment required for the entire qualification test campaign, a set of functional verification procedures and performance characterization tests were systematized and undertaken before the mechanism qualification. A preload monitoring system was developed and calibrated, and the performance of the mechanism was evaluated through the estimation of the release time and the measurement of the self-generated shock. The main results and conclusions taken from these tests are presented and discussed here.

Shock environment design for space equipment testing

“…In Figure 17, three SRS curves are presented demonstrating the repeatability of three shock tests performed with a drop angle of 20° and impactor 50. Typically, a shock test campaign requires imposing the same SRS across three orthogonal axis in the two directions of each axis, 4 for which good test repeatability is an issue. Given the good repeatability observed with the developed system, similar shock environments and test conditions may de produced for a proper shock test campaign.…”

“…The effect of a shock excitation in space hardware is largely conditioned by the peak acceleration level and frequency content of the shock excitation. 4 Based on these parameters, a qualitative characterization can be performed into three shock environment categories: 3 near-field , mid-field , and far-field . The near-field directly results of wave propagation from the source and is the most severe category considering a SRS with a continuous growing tendency with peak acceleration that can exceed 5000 g and frequencies still important above 100 kHz.…”