The Spirit and Opportunity Mars Exploration Rover Missions Ray Arvidson Washington University in Saint Louis Saint Christopher Lecture 17th International ISTVS Conference 9/19/11 1
Planetary Terramechanics• Interaction of spacecraft systems with planetary surfaces, e.g., during – Hard landing (penetrometer) – Soft landing (rockets, air bags, “sky crane”) – Hopping (proposed Comet Hopper) – Digging and sampling (Mars Phoenix Lander, MER- Spirit and Opportunity) – Drilling and sampling (Mars Science Laboratory (Curiosity), Mars 2018 Sample Caching Rover) – Roving (MER, MSL, Mars 2018 Sample Caching Rover) 2
Spirit and Opportunity Rovers •Six wheel drive with rigid wheels •Outer four wheels able to turn •Rocker-bogie suspension system •Navigation and hazard avoidance systems 3
Machine-Terrain Interaction Design, Modeling, Testing, and Best Operational PracticesMust be Used to Avoid…….. Did not happen with either Spirit or Opportunity!
Spirit Rover •Right front wheel drive actuator failed on sol 779 so subsequent drives caused rotations about that wheel •Embedded in sands of Troy after breaking through soil crust •Extrication stopped Sol 2169 to prepare for winter •Last communication March 2010 and mission over May 2011 5
Opportunity Rover •Right front wheel left rotated ~8 deg inward when azimuthal actuator failed •Shoulder IDD actuator failed so driving uses “fishing stow” and have limited deployment work space •Mini-TES no longer responding 25
2.0 x100 1.8 Timmins ratio to Zn GusevSoil Br 1.6 Adirondack 1.4 Marquette Gibraltar 1.2 1.0 x10logartihmic ratio 0.8 P S change Cl 0.6 K 0.4 Ti x2 Ca 0.2 Mn Ni 0.0 x1 Fe -0.2 Si Na Al x0.5 -0.4 Mg -0.6 -0.8 Cr -1.0 x0.1 Oxide