Simplified Model for MER Activity Planning John L. Bresina NASA Ames Research Center bresina@email.arc.nasa.gov

Mars Exploration Rover 4/7/2019 John L. Bresina

Science Objectives GOAL: Determine the aqueous, climatic, and geologic history of a site on Mars where conditions may have been favorable to the preservation of evidence of pre-biotic or biotic processes. MER is a robotic field geologist, equipped to read the geologic record of such a site. Its payload was selected to study materials at the site in detail, revealing the environmental conditions that existed when water was present. Panoramic multi-spectral images and IR spectra reveal the diversity of materials around the rover, and provide geologic context. These remote sensing data are used to select the most promising rock and soil targets for closer examination. The rover traverses to selected targets and investigates them in more detail (mineralogy, elemental chemistry, fine-scale texture) with IPS instruments. A rock abrasion tool can expose fresh rock surfaces. Additional Science Atmospheric science Thermo-physical properties Magnetic properties Strength properties Material courtesy of Steve Squyres (MER PI) 4/7/2019 John L. Bresina

MER Instruments (1) Mini Thermal Emission Spectrometer Camera-bar: Navcams, Pancams & filter wheels 4/7/2019 John L. Bresina

Dust Cover Stepper Motor MER Instruments (2) Mössbauer Spectrometer Microscopic Imager “Snowshoe” Contact Sensor Plate MI Electronics Box Contact Sensor Contact Ring Grinding Wheel Translate Axis Dust Cover MI Optics Rock Abrasion Tool Contact Ring APXS Sensor Head Dust Doors Dust Cover Stepper Motor Alpha Particle X-Ray Spectrometer 4/7/2019 John L. Bresina

Activity Dictionary AD Summary 103 activity types 43 state resources 22 numeric resources CPU_ON DEEP_SLEEP WAKE_FOR_DEEP_SLEEP POWER_THERMAL_DATA_PRODUCTS DELETE_DATA GET_ATTITUDE PANCAM_MOSAIC PANCAM_SINGLE_POSITION PANCAM_NON_REL_COLUMN PANCAM_NON_REL_RASTER PANCAM_MAST_REL_COLUMN PANCAM_MAST_REL_RASTER ROVER_DRIVE_BLIND ROVER_DRIVE_AUTONAV_DIST ROVER_DRIVE_AUTONAV_TIME ROVER_STUTTER_STEP X_COMM_HGA X_DFE_HGA X_CARRIER_LGA X_COMM_LGA X_DFE_LGA UHF_COMM MI_DUST_COVER MI_ACQ MI_SERIES MI_TIMED APXS_ACQ APXS_TIMED APXS_START_TIMED APXS_OFF_TIMED MB_ACQ MB_START_TIMED MB_OFF_TIMED MB_TIMED IDD_UNSTOW IDD_STOW IDD_OVERHEAD IDD_POSN_DEVICE IDD_TRANSLATE IDD_MOVE GENERIC_MOTOR_HEAT GENERIC_HTR_USE GENERIC_HTR_ON GENERIC_HTR_OFF HAZCAM_FRONT HAZCAM_REAR NAVCAM_MOSAIC NAVCAM_SINGLE_POSITION NAVCAM_NON_REL_COLUMN NAVCAM_NON_REL_RASTER NAVCAM_MAST_REL_COLUMN NAVCAM_MAST_REL_RASTER PMA_SINGLE_POSITION CAMERA_IMAGE_PAIR MTES_SPECTRA_OR_INTERFEROGRAMS MTES_SPECTRA_OR_INTERFEROGRAMS_ACQ RAT_GNAW RAT_TIMED PLACEHOLDER_SCI PLACEHOLDER_ENG Parameterization Example NAVCAM_MOSAIC arguments: center_point, num_mosaic_cols, num_mosaic_rows, camera_selection, az_overlap, el_overlap, subframe_area_fraction, shutter_subtraction, extra_autoexposures_per_position Abstraction Hierarchy Example NAVCAM_MOSAIC CAMERA_IMAGE_PAIR NAVCAM_MAST_REL_RASTER PMA_AZ_SLEW NAVCAM_MAST_REL_COLUMN CAMERA_BAR_SLEW PMA_SINGLE_POSITION NAVCAM_NON_REL_RASTER 4/7/2019 John L. Bresina

NDDL Model Simplifications Single abstraction level; no action expansion No model of power and thermal resources this is computed by an external program No model of data acquisition and downlink Activity parameters simplified to absolute minimum needed for scheduling: activity duration activity priority A number of engineering activities have been left out of the model 4/7/2019 John L. Bresina

Activities Modeled (1) Alpha Particle X-Ray Spectrometer (The following must occur in sequence) APXS_START APXS_ACQ APXS_OFF Mössbauer Spectrometer (The following must occur in sequence) MB_START MB_ACQ MB_OFF Microscopic Imager MI Rock Abrasion Tool RAT Instrument Deployment Device IDD_MOVE IDD_STOW IDD_UNSTOW Mobility ROVER_ROLL Hazard Cameras HAZCAM_FRONT HAZCAM_REAR 4/7/2019 John L. Bresina

Activities Modeled (2) Panoramic Cameras Navigation Cameras PANCAM_MOSAIC PANCAM_SINGLE_POSITION Navigation Cameras NAVCAM_MOSAIC NAVCAM_SINGLE_POSITION Localization via Sun-finding GET_FINE_ATTITUDE Mini Thermal Emission Spectrometer MTES_20_MRAD MTES_8_MRAD Communication X_COMM_HGA UHF_COMM CPU CPU_ON Note: there is also a pseudo-activity, called incon, used to specify initial conditions (from external sources) 4/7/2019 John L. Bresina

Flight Rules Active enforcement Passive violation detection Each flight rule can be selectively enabled & disabled via a control variable If a user operations violates an enabled flight rule, then the planner corrects the violation Only covers mutual exclusions (slide #10) Does not cover other state conditions (slide #11) Passive violation detection All passive violation detection is either enabled or disabled When passive checking is enabled, all flight rules violations are indicated to the user, but no corrective action is taken by the planner Covers both mutual exclusions (slide #10) and other state conditions (slide #11) Note: Active and passive modes can be used simultaneously 4/7/2019 John L. Bresina

Mutual Exclusions Key: Green indicates concurrency is allowed between every pair in the cross product of the row and column activities 4/7/2019 John L. Bresina

Other State Conditions Activity State Requirements IDD_Stowed state required by ROVER_ROLL IDD_UNSTOW IDD_Unstowed state required by APXS_START, APXS_ACQ, APXS_OFF MB_START, MB_ACQ, MB_OFF MI IDD_MOVE, IDD_STOW CPU_Avail state required by All activities, except APXS_ACQ & MB_ACQ Activity State Production IDD_Stowed state produced by IDD_STOW IDD_Unstowed state produced by IDD_UNSTOW CPU_Avail state produced by CPU_ON Includes 360 seconds to boot before CPU_Avail state and 540 seconds to shutdown after CPU_Avail state 4/7/2019 John L. Bresina