Initial Investigation of Reaction Control System Design on Spacecraft Handling Qualities for Earth Orbit Docking

Abstract

A program of research, development, test, and evaluation is planned for the development of Spacecraft Handling Qualities guidelines. In this first experiment, the effects of Reaction Control System design characteristics and rotational control laws were evaluated during simulated proximity operations and docking. Also, the influence of piloting demands resulting from varying closure rates was assessed. The pilot-in-the-loop simulation results showed that significantly different spacecraft handling qualities result from the design of the Reaction Control System. In particular, cross-coupling between translational and rotational motions significantly affected handling qualities as reflected by Cooper-Harper pilot ratings and pilot workload, as reflected by Task-Load Index ratings. This influence is masked -but only slightly -by the rotational control system mode. While rotational control augmentation using Rate Command Attitude Hold can reduce the workload (principally, physical workload) created by cross-coupling, the handling qualities are not significantly improved. The attitude and rate deadbands of the RCAH introduced significant mental workload and control compensation to evaluate when deadband firings would occur, assess their impact on docking performance, and apply control inputs to mitigate that impact.

Effects of Control Power and Guidance Cues on Lunar Lander Handling Qualities

“…This enables computation of the velocity components from Eqs. (13) and (14). Finally, the guidance roll and pitch angles can be computed from Eq.…”

“…The North and East components of acceleration along the reference trajectory can be determined from analytical differentiation of Eq. (13). For the general case where the vehicle is not on the reference trajectory, i.e., !…”

Dynamic Coupling and Control Response Effects on Spacecraft Handling Qualities During Docking

“…This paper reports on an experiment investigating the docking of two spacecraft in low Earth orbit (LEO); specifically, the effect of translation-into-rotation coupling and translational response-type design on handling qualities is evaluated. Companion papers report on experiments investigating the final approach and touchdown phase of lunar landing [22], a 6 DOF piloting task for docking with a space station [23], and a study of pilot aids for docking with a space station [24]. Although early research programs established RCAH as the preferred response type for attitude control, no study was done of similar control modes that command a translational velocity and allow position hold.…”

Handling Qualities Evaluation of Pilot Tools for Spacecraft Docking in Earth Orbit

“…Preliminary studies of lunar landing 11 and Earth orbit docking have been conducted. 12,13 This paper reports a follow-on experiment investigating the effect of pilot tools on handling qualities for spacecraft docking in low Earth orbit; specifically, the attenuation of handling qualities degradation arising from translation -into-rotation coupling.…”