ReviewSPACE ROBOTS

Review on space robotics: Toward top-level science through space exploration

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Science Robotics  28 Jun 2017:
Vol. 2, Issue 7, eaan5074
DOI: 10.1126/scirobotics.aan5074

Figures

Tables

  • Table 1 Successfully flown robots on Earth’s orbit, the Moon, Mars, and small bodies as of 2016.

    Launch yearMission nameCountryTargetRoverArmSamplerDrill
    1967Surveyor 3United StatesMoonx
    1970/1972/1976Luna 16/20/24Soviet UnionMoonxxx
    1970/1973Luna 17/21Soviet UnionMoonx
    1975VikingUnited StatesMarsxx
    1981/2001/2008Canadarm1/2/DextreCanadaISSx
    1993RotexGermanyEarth’s orbitx
    1996MPFUnited StatesMarsx
    1997ETS-VIIJapanEarth’s orbitx
    2003HayabusaJapanAsteroidx
    2003MERsUnited StatesMarsxxx
    2004ROKVISSGermanyISSx
    2007Orbital ExpressUnited StatesEarth’s orbitx
    2008JEMRMSJapanISSx
    2008PhoenixUnited StatesMarsxx
    2012RobonautUnited StatesISSx
    2011MSLUnited StatesMarsxxx
    2013Chang’E 3ChinaMoonx
    2004 (arrived in 2014)RosettaEuropeCometxxx
    2016Aolong-1ChinaEarth’s orbitx
  • Table 2 Growing science capabilities of NASA’s Mars robotic missions as exemplified by each generation of Mars rover.

    Mars roverMass (kg)Lifetime (sol)Distance traveled
    (km) (as of April
    2017)
    Maximum traverse
    speed (cm/s)
    Science payload
    mass (kg)
    Science results
    reported
    MPF’s Sojourner10830.10.6<1(9)
    MER’s Opportunity1854500*>4416(1012)
    MSL’s Curiosity8991667*>15.98575(13)

    *Still in operation as of 2017.

    • Table 3 Medium-term space robotic missions in the pipeline.

      Launch yearMissionCountryTargetRoverArmSamplerDrill
      2017Chang’E 5ChinaMoonxxxx
      2018Chandrayaan 2IndiaMoonx
      2018 (to arrive)OSIRIS-REx
      Sample Return
      United StatesNEAxx
      2018InSightUnited StatesMarsxxx
      2018Chang’E 4ChinaMoon (farside)x
      2019SLIMJapanMoonxxxx
      2020Mars 2020United StatesMars
      2020ExoMars 2020EuropeMarsxxx
      2020+Chinese Space
      Station
      ChinaEarth’s orbitx
      2025Phobos sample
      return
      Europe and RussiaPhobosxx
    • Table 4 Long-term space robotic mission concepts (4).

      ISRU, in situ resource utilization.

      DestinationProposed mission
      concepts
      Proposed robotic
      locomotion
      Earth’s orbitSpace debris removal,
      on-orbit servicing, and
      assembly
      Arm, hand/gripper,
      harpoon
      MoonSample return, ISRU,
      exploration of
      permanently shaded
      craters, prepare for
      manned base
      Rover, arm, sampler, drill
      MarsSample return, ISRU,
      crewed base
      Aeroshell, airplane,
      helicopter, balloon,
      hopper, swarms
      VenusExplorationBalloon
      MercuryExplorationRover
      AsteroidSample return, ISRURover, hopper, arm,
      harpoon
      TitanExplorationAeroshell, aerobot,
      balloon, lake lander,
      submarine, ship,
      cooperative robots
      Europa/EnceladusExplorationSubsurface, submarine,
      hopper
      Gas giantsExplorationBalloon
    • Table 5 Diversified locomotion for future space robots (4).

      Robotic platformRobotic locomotion
      Land surface- Wheeled rover
      - Tracked rover
      - Legged rover
      - Rolling (e.g., ball or sphere) rover
      - Hopper
      - Hovercraft
      Airborne- Quadcopter, helicopter, or ornithopter
      - Plane or glider
      - Balloon, montgolfier, aerobot
      Subsurface- Drill (e.g., ice drilling or melting, rotary drilling, percussive drilling, dual reciprocating drilling)
      - Submarine, submersible
      Manipulation- Arm
      - Hand, gripper
      - Sampler (e.g., corer, scoop)
      Water surface- Vertical profiling float
      - Boat, ship
    • Table 6 Examples of novel robotic locomotion concepts for future space exploration (all images courtesy of JPL/NASA).
      Embedded ImageMars helicopter (36)
      Mars helicopter is proposed to facilitate surface rover operations. Despite
      the thin Martian atmosphere (only 0.6% that of Earth), the solar-powered
      Mars helicopter at 1 kg in mass and with a 1.1-m-long rotor, would scout
      ahead of a surface rover, providing critical imagery to enable the rover to
      drive up to three times as far per sol.
      Mars airplane (37)Embedded Image
      Whereas the extremely thin Martian atmosphere makes air vehicles
      challenging, a Mars airplane is proposed as the Preliminary Research
      Aerodynamic Design to Land on Mars (or Prandtl-m). A Mars airplane could
      be released as part of the entry, descent, and landing ballast for a future
      Mars-landed mission to acquire unique airborne imaging of the Martian
      surface.
      Embedded ImageTitan aerobot (38)
      Test flight in the Mojave Desert, CA, USAWith a dense methane atmosphere providing strong lift and weak gravity,
      an aerobot is an ideal vehicle to explore Titan, a moon of Saturn. Titan is
      of great interest to scientists because of its abundant methane as a
      possible ingredient for life and its liquid methane lakes on the surface.
      Aerobots and montgolfiers have been proposed and tested to develop
      technologies for this ambitious robotic mission.
      Mars dual-axel rover (39)Embedded Image
      Recent interest in recurrent slope linnae as liquids on the surface of Mars has
      spurred interest in robotic access to extreme slopes to study these science
      phenomena. The axel robot is a single axle with tether designed to rappel
      down steep slopes. In a dual-axel rover configuration, one axel would
      remain at the top of the slope as an anchor to allow the other axel to rappel
      down the slope.
      Embedded ImageUnderwater vehicle (40)
      BRUIE Field trials in Alaska, USAScientists now believe that there are at least eight ocean worlds in our solar
      system. These liquid oceans may provide the best chance for life outside
      Earth in our solar system. BRUIE, Buoyant Rover for Under Ice Exploration
      underwater vehicle, is a rover designed to roam the underside of the icy
      shell at the top of an ocean (such as on Europa, Enceladus, or other ocean
      worlds). BRUIE could rove along the underside of ice—adjusting its
      buoyancy to maintain contact or hop at will. Its position at the water-ice
      interface offers it a great position to explore this unique surface where
      evidence of life may exist.
    • Table 7 Technological needs and challenges for space robotics in the coming decades.
      AreasGoalsTechnological needs or challengesRelevance to achieving top-level science
      Sensing and
      perception
      To provide situational
      awareness for space
      robotic agents,
      explorers, and
      assistants
      - New sensors
      - Sensing techniques
      - Algorithms for 3D perception, state estimation,
      and data fusion
      - Onboard data processing and generic software
      framework
      - Object, event, or activity recognition
      The sensors provide the vast bulk of the direct
      science:
      -Increases in instruments, both remote sensing and
      in situ enable more precise measurements (e.g.,
      spatial, spectral resolution, while reducing
      volume, mass, and power).
      - New types of instruments are emerging. Imaging
      spectroscopy to determine composition; lidar for
      3D mapping; interferometric radar for change
      detection, structure; sample processing for life
      detection and astrobiology to enable new
      measurements for new types of science.
      Mobility or locomotionTo reach and operate
      at sites of scientific
      interest on
      extraterrestrial
      surfaces or free
      space environments
      - Mobility on, into, and above an extraterrestrial
      surface using locomotion like flying, walking,
      climbing, rappelling, tunneling, swimming,
      and sailing
      - Melting through the kilometers-thick ocean
      worlds’ ice shells of Europa, Enceladus, or Pluto
      - Manipulations to make intentional changes in
      the environment or objects using locomotion
      like placing, assembling, digging, trenching,
      drilling, sampling, grappling, and berthing
      Locomotion represents the ability to explore an
      environment, such as rovers, aerobots, and
      submarines. Melting through ocean worlds’ ice
      shells enables access to habitable oceans
      underneath. Digging, trenching, and coring enable
      access to materials without atmospheric
      contamination (e.g., Mars geology) or radiation
      (e.g., Europa astrobiology).
      High-level autonomy
      for system and
      subsystems
      To provide robust and
      safe autonomous
      navigation,
      rendezvous, and
      docking capabilities
      and to enable
      extended-duration
      operations without
      human interventions
      to improve overall
      performance of
      human and robotic
      missions. To enable
      closed-loop science
      for more efficient,
      novel science (e.g.,
      tracking a dynamic
      plume at a comet)
      - GNC algorithms
      - Docking and capture mechanisms and interfaces
      - Planning, scheduling, and common autonomy
      software framework
      - Multi-agent coordination
      - Reconfigurable and adjustable autonomy
      - Automated data analysis for decision-making,
      fault detection, isolation and recovery/IVHM,
      and execution
      - Enhanced guidance navigation and control means
      higher precision navigation for better science
      measurements. Scheduling, execution, and
      integrated vehicle health management enable
      more productive science time for vehicles.
      - Automated science analysis and scheduling enable
      closing the loop without ground in the loop,
      enabling more science cycles per mission (i.e.,
      higher productivity and unique, opportunistic
      science).
      Human-robot
      interaction
      To enable humans to
      accurately and
      rapidly understand
      the state of the
      robot in
      collaboration and
      act effectively and
      efficiently toward
      the goal state
      - Multimodal interaction; remote and supervised
      control
      - Proximate interaction
      - Distributed collaboration and coordination
      - Common human-system interfaces
      Virtual reality and augmented reality allow more
      natural interfaces to analyze vast acquired data
      streams. Virtual reality and augmented reality also
      allow for natural means of vehicle controlling such
      as by reach, touch, and gesture.
      System engineeringTo provide a
      framework for
      understanding and
      coordinating the
      complex
      interactions of
      robots and
      achieving the
      desired system
      requirements
      - Modularity, commonality, and interfaces
      - Verification and validation of complex adaptive
      systems
      - Robot modeling and simulation
      - Software architectures and frameworks
      - Safety and trust
      High stakes in billions require a reliable mission. As
      systems become increasingly complex, being able
      to characterize robotic behavior (especially for
      multivehicle swarms) becomes increasingly
      challenging.

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