ESA GNC Conference Papers Repository

This paper describes the architecture and design of the AOCS/GNC system developedfor the ALINA Moon lander by DLR and PTS. Driving requirements are the need forcomplete autonomy during the landing phase, the required absolute landing accuracy of500m x 750m and the touch down conditions (i.e. horizontal speed limit, vertical speedlimit, yaw/pitch angle limits). The paper gives an overview about the overall mission anddescribes the actuator and the sensor configurations as well as the computer architecture.The AOCS modes are defined as well as the objectives, the initial, target and exit con-ditions and the actuator/sensor configuration for each mode. The paper expands on the3-DoF system used to control the attitude/rate during the Cruise & Orbital Phase andthe 6-DoF GNC system controlling the position/velocity (outer-loop) and attitude/rate(inner-loop)duringtheDescentandLandingPhase, utilizingaCraterNavigation(CNav)based navigation filter and an optional Hazard Detection and Avoidance (HDA) system.An overview about the redundancy concepts and general FDIR approach on AOCS levelis given. The paper offers a high-level overview about the approaches and technologiesused in all major algorithmic areas. Finally, Model in the Loop test results are presented,showing an expected landing accuracy of 20 meters and an HDA maneuver executionaccuracy of about 10 meters.