Analysis, Test and Simulation of Landing System Touchdown Dynamics

Abstract

Future exploration missions pose demanding requirements towards the access by vehicles to scientifically interesting sites on planetary surfaces. These stem particularly from the need of more flexibility in site selection, improved payload to vehicle mass ratios and higher mission success probabilities. The Landing Technology group of the DLR Institute of Space Systems is focusing on the development and verification of experimental and analytical methods for the investigation of the touchdown dynamics of landing system, its capabilities the embedding into the landing site assessment. Core element for the experimental investigation is the Landing & Mobility Test Facility (LAMA), which allows touchdown testing under Earth gravity and under a reduced gravitational environment using an active off-loading device. The test article for investigation of legged landing systems is a modular Lander Engineering Model (LEM) designed by the Astrium ST (Bremen), representing today's European mission scenarios to the Moon and Mars such as the ESA Lunar Lander or the ESA Mars Precision Lander. Another test object recently under retesting is the Rosetta lander Philae representing a touch down system concept developed for small body landings. Usually not all relevant environmental properties of the target landing site can be provided in one single and complete test, any verification approach has to be supported by adequate numerical analyses. Thus, another key topic for the verification of the touchdown performance of a landing system is the accurate analytical and numerical representation of the flight system, its touchdown conditions and the landing site. In this area the research focuses on the development of high fidelity engineering simulations of the vehicle-to-terrain/soil interaction. The landing site characterization and assessment focuses on the development of landing site assessment methods and tools and to provide terrain models for engineering simulations (both touchdown dynamics and/or hazard detection& avoidance simulations). In return landing system performance limits are mapped onto cartographic landing site representations to support the landing safety assessment. This poster outlines the test facility, simulation and analysis tools developed by the working group and used in recent landing missions.