Randel Lindemann

Mars exploration rover mobility development

The Mars Exploration Rover (MER) Project was launched in mid-2000 to land two mobile exploration platforms at different science targets on the red planet. The centerpiece of each mission is the rover and its scientific payload. Spirit and Opportunity are identical vehicles, and each carries the same science payload and engineering subsystems. NASAs current Mars program is once again focused on missions to the Martian surface to answer fundamental questions of the extent Mars ever supported a liquid water environment on its surface, and hence the planets ability to have sustained life

Simulations of Mars Rover Traverses

Artemis (Adams-based Rover Terramechanics and Mobility Interaction Simulator) is a software tool developed to simulate rigid-wheel planetary rover traverses across natural terrain surfaces. It is based on mechanically realistic rover models and the use of classical terramechanics expressions to model spatially variable wheel-soil and wheel-bedrock properties. Artemiss capabilities and limitations for the Mars Exploration Rovers (Spirit and Opportunity) were explored using single-wheel laboratory-based tests, rover field tests at the Jet Propulsion Laboratory Mars Yard, and tests on bedrock and dune sand surfaces in the Mojave Desert. Artemis was then used to provide physical insight into the high soil sinkage and slippage encountered by Opportunity while crossing an aeolian ripple on the Meridiani plains and high motor currents encountered while driving on a tilted bedrock surface at Cape York on the rim of Endeavour Crater. Artemis will continue to evolve and is intended to be used on a continuing basis as a tool to help evaluate mobility issues over candidate Opportunity and the Mars Science Laboratory Curiosity rover drive paths, in addition to retrieval of terrain properties by the iterative registration of model and actual drive results.

An integrated coring and caching concept

An integrated concept for core sample acquisition and caching with potential application to a Mars caching mission has been developed. The concept utilizes a five degree-of-freedom manipulator arm to deploy a rotary percussive coring tool as well as to provide alignment, feed, and preload for the tool. The tool provides coring, core break-off, core retention and bit capture and release for bit change-out. In this concept, a sample is acquired directly into its sample tube in the coring bit and bit change-out is used to transfer the sample to the caching subsystem where it is sealed and stored. 1 2

Dynamic testing and simulation of the Mars Exploration Rover

In January of 2004, NASA landed two mobile robotic spacecraft on the surface of Mars as part of the Mars Exploration Rover (MER) project. Named Spirit and Opportunity, each of these rovers is performing their separate scientific missions of exploration more than a year after landing. The Mars Exploration Rovers represent a great advance in planetary rover technology. Part of that advance is represented by the mobility capabilities of these vehicles. At the 1.5 year mark, the two vehicles have traversed more than 10 km over broad plains, craters, rocks, and hills. In order to assess the mobility characteristics of the rovers in the Mars environment, an engineering model vehicle was tested before the mission launches in a representative environment of slopes, rock obstacles, and soft soil. In addition, to gain better insight into the rovers’ capabilities, a dynamic model of the rovers was created in the software package ADAMS. The rover model was then used to simulate many of the test cases, which provided a means for model correction and correlation. The results and lessons learned of the test and dynamic simulation of the MER vehicles is provided in this paper. The results from the test and simulation program allowed Spirit and Opportunity to be used in terrain well outside of the original mission requirements. The resulting increase in terrain access, led to substantial additions to the missions science return.Copyright