NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

A Zero-Gyro Safemode Controller for HST

F. Landis Markley1 and John D. Nelson2
1NASA Goddard Space Flight Center
2Lockheed Missles & Space Company, Inc.

1992 AIAA Guidance, Navigation and Control Conference
August 10-12, 1992, Hilton Head Island, SC
A Collection of Technical Papers, Part 3, pp. 1445-1459


The purpose of this paper is to document the Zero-Gyro Sunpoint mode for Hubble Space Telescope, a safemode designed to ensure a power positivestate without the use of rate gyros.  This paper presents an overview of the Zero-Gyro Sunpoint algorithm, followed by details of the algorithm, control system design, and simulation results.  A new, related safemode test, the System Momentum Test, is also discussed.

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