Control of an experiment to measure acoustic noise in the space shuttle

Abstract

This thesis describes the potential use of a general-purpose controller autonomously to measure acoustic vibration in the Space Shuttle Cargo Bay during launch. The experimental package will be housed in a Shuttle Get Away Special (GAS) canister. We have implemented the control functions with software written largely in the C programming language. We use an IBM MS-DOS computer and C cross-compiler to general Z-S0 assembly language code, assemble and link this code, and then transfer it to EPROM for use in the experiment's controller. The software is written in a modular fashion to permit adapting it easily to other applications. The software combines the experimental control functions with a menu-driven, diagnostic subsystem to ensure that the software will operate in practice as it does in theory and under test. The experiment used many peripheral devices controlled by the software described in this thesis. These devices include: a solid-state data recorder, a bubble memory storage module, a real-time clock, an RS-232C serial interface, a power control subsystem, a matched filter subsystem to detect activation of the Space Shuttle's auxiliary power units five minutes prior to launch, a launch detection subsystem based on vibrational and barometric sensors, analog-to-digital converters, and a heater subsystem. The matched filter design is discussed in detail in this thesis, and the results of a computer simulation of the performance of its most critical sub-circuit are presented.