Active Control Technology Experience with the Space Shuttle in the Landing Regime

The 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 environmental. Approach and landing test flights indicated a tendency for 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 pilot-induced oscillatory motions. Fixed-base, moving-base, and in-flight simulations were used for the evaluations, and in general, flight simulation was the only reliable means of assessing the low-speed longitudinal flying qualities problems. Overall, the orbiter control system and operational procedures have produced a good capability for routinely performing precise landings in a large, unpowered vehicle with a low lift-to-drag ratio

Natural environment support guidelines for space shuttle tests and operations

All space shuttle events from launch through solid rocket booster recovery and orbiter landing are considered in terms of constraints placed on those operations by the natural environment. Thunderstorm activity is discussed as an example of a possible hazard. The activities most likely to require advanced detection and monitoring techniques are identified as those from deorbit decision to Orbiter landing. The inflexible flight plan will require the transmission of real time wind profile information below 24 km and warnings of thunderstorms or turbulence in the Orbiter flight path. Extensive aerial reconnaissance and communication facilities and procedures to permit immediate transmission of aircraft reports to the mission control authority and to the Orbiter will also be required

The orbiter air data system

Air data parameters are required during Orbiter atmospheric entry for use by the autoguidance, navigation, and flight control systems, and for crew displays. Conventional aircraft calibrations of the Orbiter air data system were not practicable for the Space Shuttle, therefore extensive wind tunnel testing was required to give confidence in the preflight calibrations. Many challenges became apparent as the program developed; in the overall system design, in the wind tunnel testing program, in the implementation of the air data system calibration, and in the use of the flight data to modify the wind tunnel results. These challenges are discussed along with the methods used to solve the problems