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Pangaeus �(CLPS Demonstration)

Stephen Hunt

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Motivation

There are a handful of reasons we are going back to the moon, but one of them is to further understand and harvest its resources.

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Given its rocky, unwelcoming nature, it will not be a great home, but it can serve as a depot of sorts with materials (silicon, iron, magnesium, water, etc.) being its number one export.

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Therefore, an early goal of the Artemis missions is to identify the materials available and develop ways to mine them, thus enabling in-situ resource utilization [1].

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Such resource exploration and gathering can be efficiently done by robots.

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Water Ice Regions

Moon Rock

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Current Work on Lunar Robotics

  • Astrobotic is a big player in lunar robotics with involvement in each of the following rovers.
  • Viper is currently a rover with funding under the Commercial Lunar Payload Services (CLPS) initiative. It will search out and map locations of lunar water ice [3].
  • CubeRover is leading the way for small robotics with funding from NASA. It could potentially be used for scouting [2].
  • MoonRanger is set to be an autonomous lunar rover. This breaks away from the traditional command / control architecture [4].
  • Small robotics honorable mentions – Polaris, MINERVA-II1A/B
  • There is lots of work in advancing rover technology.

Viper

CubeRover

MoonRanger

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The Lunar Night Doth Not Care

  • The lunar night is brutal. It can get down to -173.15 °C on the lunar surface and last about 14 Earth days [5]. This, in contrast to the lunar day temperature of approximately �126 °C.
  • This is much too cold, even for robots. Electromechanical failures can occur.
  • VIPER plans to park itself at higher elevations during the lunar night so that it may experience a 4-day night. In addition, its mission is expected to last only 100 days, freezing once it experiences a lunar night longer than 4 days [3].

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Data is for equatorial regions

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Subsurface Sanctuary

30 cm

-173.15 °C

-23.15 °C

  • The lunar surface is a thermal insulator. At 30 cm, temperatures become more stable at around �-23.15 °C [5].
  • This is much more manageable.
  • It provides an interesting option. Bury robots underground so they may survive the lunar night.

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  • NOTE: No data at higher latitudes. We are assuming conditions are not as good given the presence of ice.

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Data is for equatorial regions

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Subsurface Bootstrapping

  • The Moon does not have a magnetic field and is exposed to the vacuum of space, having no atmosphere. These are extremely important to Earth’s livable climate.
  • Subsurface dwelling could very well end up being an integral part of Moon exploration both in the near and distant future.
  • Instead of utilizing the mass of the atmosphere for shielding, use the mass of the ground.
  • Regolith already proven to be thermal insulator.
  • Algorithmic problem – who digs the first hole?

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Enter Pangaeus

Small form factor robots can burrow themselves under the lunar surface during lunar night.

Swarm behavior allows them to robustly perform meaningful work during lunar day.

  • Swarm of 10 robots
  • Approximate size of 6U CubeSat�(30 L x 20 W x 10 H cm)
  • Modular with different sub-jobs
    • Digger / regolith transport
    • Grabber / rock transport
    • Power production
  • Autonomous with command-and-control capabilities
  • Solar powered

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Trench Architecture

  • Swarm digs an approximately�200 W x 80 L x 60 H cm trench.
  • They place an accordion like, rectangular duct within the trench with its entrance above ground. This duct is delivered from Earth as part of the mission.
  • Regolith is then filled back into the trench, covering the duct and providing the necessary insulation.
  • Once the lunar night arrives, they enter the buried duct for safety.

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  • Small robots can accomplish this given the soft powdery regolith.
  • 14 Earth days is long enough to get this done.

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Digging (RASSOR)

  • NASA’s Regolith Advanced Surface Systems Operations Robot (RASSOR) is designed to excavate lunar regolith [6].
  • Utilizes two spinning drums in order to overcome problems pertaining to low gravity excavation.
  • Tank tread allows for easy regolith traversal.

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  • Take advantage of this existing technology for digging into the lunar surface.

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Other Design Considerations

  • Robotic arms for picking up larger rocks and for pulling duct into trench. They can also help relocate and place any 3D printed / sintered objects.
  • Robots dedicated to power production.
    • Can deploy larger solar panels.
    • During lunar night, solar panels can be stowed away, keeping them safe from the powdery regolith.
  • Some outfitted with cameras
  • Wireless comms between robots
  • Radio link to orbiting comms system
  • Swarm enabling software

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Mission Architecture

  • This is a demonstration
  • Travel as part of a CLPS mission
    • Can hitch a ride on Astrobotic’s Griffin lander
  • Primary mission objective (Proof of Concept):
    • Surviving lunar night
  • Secondary mission objective:
    • During next lunar day, swarm bots get to work with lunar regolith
    • Consolidate regolith, ready for sintering
    • Relocate any sintered tiles, configuring them into a desired structure

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Serving Artemis

  • Artemis Goals [1]:
    • In-situ resource utilization technologies for collecting, processing, storing, and using material found or manufactured on the Moon or other planetary bodies.
    • Extreme environment technologies that enable systems to operate throughout the range of lunar surface temperatures.
    • Excavation and construction technologies that enable affordable, autonomous manufacturing or construction.
    • Advance long-term robotic exploration of the Moon.
    • Preparation for Mars.
  • This architecture is:
    • Scalable
    • Flexible
    • Robust
  • This architecture will kick off the process towards a sustainable, naturally protected subsurface human and robotic presence on the Moon

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Future Considerations

  • Study power consumption while in hibernation. Do we maintain connectivity, risking total power loss? Do we add another power source?
  • Study radiation exposure at proposed depths. Are these depths enough for sufficient radiation shielding?
  • Study impact of regolith on solar power production.
  • Potential to load new software, over the air, reconfiguring swarm for new tasks.

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References

  1. USA, NASA. (2020). Artemis Plan - NASA’s Lunar Exploration Program Overview (pp. 35). https://www.nasa.gov/sites/default/files/atoms/files/artemis_plan-20200921.pdf
  2. Roston, B. (2020, October 03). Astrobotic ships its ultralight shoebox-sized rover to NASA for testing. Retrieved November 03, 2020, from https://www.slashgear.com/astrobotic-ships-its-ultralight-shoebox-sized-rover-to-nasa-for-testing-03640914/
  3. Chen, R. (2020, February 05). VIPER Mission Overview. Retrieved November 03, 2020, from https://www.nasa.gov/viper/overview
  4. Astrobotic Awarded $5.6 Million NASA Contract to Deliver Autonomous Moon Rover. (2019, July 1). Retrieved November 03, 2020, from https://www.astrobotic.com/2019/7/1/astrobotic-awarded-5-6-million-nasa-contract-to-deliver-autonomous-moon-rover
  5. Malla, R. B., & Brown, K. M. (2015). Determination of temperature variation on lunar surface and subsurface for habitat analysis and design. Acta Astronautica, 107, 196-207. doi:10.1016/j.actaastro.2014.10.038
  6. Mueller, Robert & Cox, Rachel & Ebert, Tom & Smith, Jonathan & Schuler, Jason & Nick, Andrew. (2013). Regolith Advanced Surface Systems Operations Robot (RASSOR). IEEE Aerospace Conference Proceedings. 1-12. 10.1109/AERO.2013.6497341.

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Thank You!

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