Space Shuttle longitudinal landing flying qualities

Abstract

The Space Shuttle program took on the challenge of providing a manual landing capability for an operational vehicle returning from orbit. Some complex challenges were encountered in developing the longitudinal flying qualities required to land the Orbiter manually in an operational environment. Approach and landing test flights indicated a tendency of pilot-induced oscillation near landing. Changes in the operational procedures reduced the difficulty of the landing task, and an adaptive stick filter was incorporated to reduce the severity of any pilotinduced oscillatory motions. Fixed-base, moving-base, and in-flight simulations were used for the evaluations. In general, flight simulation proved to be the best means of assessing the low-speed longitudinal flying qualities problems. Overall, the Orbiter control system and operational procedures produced a good capability to perform routinely precise landings with a large, unpowered vehicle that has a low lift-to-drag ratio. Nomenclature ALT= approach and landing test DFBW = digital fly-by-wire FSAA = flight simulator for advanced aircraft L/D = lift-to-drag (ratio) PIO(s) = pilot-induced oscillation(s) STS = space transportation system TAEM = terminal area energy management TIPS = total in-flight simulator VMS = vertical motion simulator

Free Enterprise: Contributions of the Approach and Landing Test (ALT)Program to the Development of the Space Shuttle Orbiter

“…High cockpit location and poor forward visibility also contribute to the pilot's inability to judge both attitude and altitude near touchdown. 23 The PIO suppression filter designed following the DFBW and TIFS investigations was added to the orbiter's flight control system software prior to OFT-1/STS-1 (originally scheduled for 1979, but later slipped to April 1981). Although the filter virtually eliminated high-frequency PIO tendencies, it was not designed to improve lowfrequency, large-amplitude heave mode characteristics near touchdown produced by poor flight path control.…”

Orion Capsule Handling Qualities for Atmospheric Entry

“…The space shuttle program conducted some handling qualities studies of final approach and landing/rollout. 3 In 2007, NASA began another effort to study spacecraft handling qualities in preparation for a new generation of piloted spacecraft intended to replace the Space Shuttle and travel beyond Earth orbit. [4][5][6][7][8][9][10][11] Although vehicle control during entry is usually done with an automated system, Apollo and current-day requirements (e.g.…”

Handling Qualities Evaluation for Spacecraft Docking in Low Earth Orbit

“…Handling qualities have been assessed for some space vehicles; [7][8][9] however, the focus of these studies was to evaluate and/or address deficiencies in the handling qualities of an existing point design for a specific vehicle. A more systematic approach would map out handling qualities variations over a broad range of design variables to determine desirable regions in the design space for a class of vehicles.…”