The Role of Optimization and Deduction in Reactive Systems P. Pandurang Nayak NASA Ames Research Center Brian C. Williams MIT

Autonomous Mars Airplane courtesy NASA Ames

Cassini Maps Titan ~ 1 billion $ 7 years to build ~ ground operators 100 million $ 2 year build 0 ground ops courtesy JPL The Cost of Autonomy: Cassini

courtesy JPL Started: January 1996 Launch: October 15th, 1998 Experiment: May 17-21

Procedural Executive Planner & Scheduler Mission Manager ESL Monitors Remote Agent AMES / JPL Model-based Executive for Fault Protection Command dispatch Fault protection Attitude control

Model-based Execution as a kind of Stochastic Optimal Controller Controller Plant mode identification mode reconfiguration s’(t)  (t) f f s (t) g g o(t) Models Livingstone Goals Indirect sensing and control. Probability, optimality, logic & deduction.

OPSAT Generate: Best Kernel Assignments –Generate minimal covering of conflicts, in best first order. –Compact encoding grows agenda linearly with checked states Test: SAT –Unit propagation dominates, ITMS efficiently tracks changes. generate successors generate successors Best First Agenda Check Consistency Optimalfeasiblesolutions Checkedsolutions ITMS conflict database conflict database Kernelassignments

Remote Agent Experiment May 17-18th experiment Generate plan for course correction and thrust Diagnose camera as stuck on –Power constraints violated, abort current plan and replan Perform optical navigation Perform ion propulsion thrust May 21th experiment. Diagnose faulty device and –Repair by issuing reset. Diagnose switch sensor failure. –Determine harmless, and continue plan. Diagnose thruster stuck closed and –Repair by switching to alternate method of thrusting. Back to back planning See rax.arc.nasa.gov

Remote Agent Experiment May 17-18th experiment Generate plan for course correction and thrust Diagnose camera as stuck on –Power constraints violated, abort current plan and replan Perform optical navigation Perform ion propulsion thrust May 21th experiment. Diagnose faulty device and –Repair by issuing reset. Diagnose switch sensor failure. –Determine harmless, and continue plan. Diagnose thruster stuck closed and –Repair by switching to alternate method of thrusting. Back to back planning See rax.arc.nasa.gov

Remote Agent Team Members Douglas BernardJPL Steve ChienJPL Greg DoraisAmes Julia DunphyJPL Dan DvorakJPL Chuck FryAmes Ed GambleJPL Erann GatJPL Othar HanssonThinkbank Jordan HayesThinkbank Bob KanefskyAmes Ron KeesingAmes James KurienAmes Bill MillarAmes Sunil MohanFormida Paul MorrisAmes Nicola MuscettolaAmes Pandurang NayakAmes Barney PellAmes Chris PlauntApple Gregg RabideauJPL Kanna RajanAmes Nicolas RouquetteJPL Scott SawyerLMMS Rob SherwoodJPL Reid SimmonsCMU Ben SmithJPL Will TaylorAmes Hans ThomasAmes Michael Wagner4th Planet Greg WhelanCMU Brian C. WilliamsAmes David YanStanford

Outline Deep Space One and Remote Agent Model-based Execution OPSAT and the ITMS Model-based Reactive Planning Space Robotics