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Lu.T.E.

Lunar Lava Tube Exploration

by Zach Bates

Credit: NASA’s Johnson Space Center

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Context

Discovery & Confirmation:

2009 - SELENE captured images of deep vertical holes (Skylights) on lunar surface.¹
The Lunar Reconnaissance Orbiter(LRO) confirmed skylight floor extends at least several meters eastward and westward under the ceiling (Suggesting Lunar Lava Tube Presence).¹

Current State:

Over 200 Skylights imaged by LRO.
Skylights found on Earth, Moon, Mars, Venus, Phobos, Eros, Gaspra, Ida, Enceladas, and Europa.
New NASA Directive: Go to the Moon and Mars and stay there.
No dedicated robotic missions for skylight and lunar lava tube exploration.

In 2009, large, deep vertical holes (Skylights) were discovered at Marius Hills, Mare Tranquillitatis, and Mare Ingenii using lunar surface image data acquired by the high-resolution Terrain Camera (TC) onboard SELENE (Kaguya)

Gravitometric observations by the GRAIL spacecraft suggest the presence of lunar lava tubes with widths of over 1 km. Assuming a width-to-height ratio of 3:1, such a structure can remain stable with a ceiling that is 2 m thick. Lava tubes at least 500 m underground can theoretically remain stable with widths of up to 5 km ¹¹

The Lunar Reconnaissance Orbiter has now imaged over 200 pits. that show the signature of being skylights into subsurface voids or caverns. Skylight diameters range from about 5 m (16 ft) to roughly 900 m (3,000 ft),⁶ although some of these are likely to be post-flow features rather than volcanic skylights

The Lunar Reconnaissance Orbiter Narrow Angle Camera performed higher resolution nadir and oblique angle observations and confirmed the floor of the holes extends at least several meters eastward and westward under the ceiling

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Skylight Connected to Lava Tube

Whittaker W. (2012). Technologies enabling exploration of skylights, lava tubes and caves. NASA, US, Report, no. NNX11AR42G

Skylight

Lava Tube

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Potential Sites

= Skylights

Image Credit: Wagner, R., & Robinson, M. (2014). Distribution, formation mechanisms, and significance of lunar pits. Icarus, 237, 52–60. https://doi.org/10.1016/j.icarus.2014.04.002

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Subsurface Voids Confirmed

Reference:happaz, Loic & Sood, Rohan & Melosh, Jay & Howell, Kathleen & Blair, David & Milbury, Colleen & T. Zuber, Maria. (2017). Evidence of Large Empty Lava Tubes on the Moon using GRAIL Gravity: Evidence of Lunar Lava Tubes from GRAIL. Geophysical Research Letters. 44. 10.1002/2016GL071588

We utilized two types of gravity data. The free-air anomaly (FA) is the gravitational potential directly mea-

sured by the relative accelerations of the two GRAIL spacecraft minus the average lunar gravitational accel-

eration. It therefore includes the effects of both subsurface density variations and topography. The

Bouguer anomaly (BA) is calculated by assuming that topographic features have a nominal density

(2560 kg/m, the Moon’s average crustal density) and then subtracting the gravitational contribution of the

topography. We applied our gradiometry and cross-correlation techniques to both gravity ﬁelds. Because

SR are mass deﬁcits similar to empty lava tubes, but with known trough-like topography, they should appear

in FA but not BA. Buried empty lava tubes, which lack a topographic expression, should appear in both FA and

BA. We thus correlated FA and BA maps and accepted only those features that appeared in bot

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Lunar Lava Tubes Significance

Protection from ⁴

Radiation
Extreme temperature variations
High speed meteorites
Potentially regolith dust

Logistics ⁴

Larger fraction of the landed mass to be dedicated to life support and science mission support
Potential access to protected mineral deposits and volatiles

Scientific Knowledge ⁴

Permit direct examination of pristine lunar bedrock
Provide understanding of the Moon’s volcanic history
Insights into origins and morphology
Potential for biological signatures

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2018 National Space Exploration Strategic Goals

Compliments 4 of 5

Lead Emplacement Capabilities
Foster Scientific Discovery and Characterize Lunar Resources
Return U.S. Astronauts for Sustained Campaign
Demonstrate Capabilities for Mars on Moon

Credit: Reference 5

Benefits ³

Longer duration missions without risk of radiation overdosing
Better reliability and a more diverse set of scientific technology
Larger habitat area in which to work

substances that are easily evaporated at normal temperatures

The National Space Exploration Campaign has five strategic goals:

1. Transition U.S. human spaceflight in LEO to commercial operations that support NASA and the needs of an emerging commercial economy.

2. Lead the emplacement of capabilities that support lunar surface operations and facilitate missions beyond cislunar space

3. Foster scientific discovery and characterization of lunar resources through a series of robotic missions.

4. Return U.S. astronauts to the surface of the Moon for a sustained campaign of exploration and utilization.

5. Demonstrate on the Moon the capabilities required for human missions to Mars and other destinations.

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Mission Architecture: Currently

Credit: Reference 8

Ramped entrance: Demonstrated

Tyrolean entrance: Demonstrated

Lacus Mortis pit

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Infrastructure Required for Safe Mission

Flyover: Initial pit characterization
Lander: Deliver to surface
Surface Explorer: Pit rim characterization
Descent Infrastructure: Tyrolean entrance
Pit Descent: Deliver to pit floor
Pit Infrastructure Link: Data and power transmission
Sub Surface Explorer: 3D mapping of lava tube

Credit: Reference 8

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Mission Architecture: Challenges

High uncertainty in target terrain:

Aperture size, entrance type, depth, and lava tube presence all vary.

High Risk of Failure: Landing, loose scree slope, rough terrain, dangerous skylight entry/descent, no access to sun for power subterranean explorer, novel communication and data transmission, high levels of autonomy needed for novel environment…etc

Credit: Reference 8

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Mission Architecture: Low Cost Probes

Utilize the Lunar Gateway, CLIPS, and advanced robotics to burn down risk of a non profitable skylight mission.

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Low Cost Probes

Lunar Surface Rovers and Landers could be equipped with multiple probes allowing for short duration reconnaissance missions.
Many skylights can be characterized at a pace that far exceeds one off dedicated missions.
Affordably determine cave systems feasible for dedicated robotic and human exploration.

Credit: Reference 8 & 9

Credit: Reference 10

Credit: Reference 11 & 12

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Low Cost Probes: Snake Bot Example

https://www.sintef.no/en/latest-news/snake-robots-in-space/

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Currently Planetary Robotic Exploration:

Expensive
Risk Averse
Government Led
Data Collection and Analysis
Low Turnover Rate

Future of Planetary Exploration:

Low Cost
Risk Tolerant
Privately Run
Robotic and Manned Mission Planning
High Turnover Rate
In Situ Exploration

Paradigm Shift: “You can go there.”

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Merits and Limitations

Whittaker W. (2012). Technologies enabling exploration of skylights, lava tubes and caves. NASA, US, Report, no. NNX11AR42G

Merits:

Expedite exploration of other celestial bodies.
The technology can be tested on earth analogues.
Technology has been demonstrated.

Limitations:

Relies upon architecture yet to be set in place.

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Questions

Credit:Human exploration of a lava tube on the Moon (Composite image - Mars Institute/Pascal Lee)

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References

�1. “Detection of Intact Lunar Lava Tubes in the Data from SELENE (Kaguya) Radar Sounding.” ISAS, www.isas.jaxa.jp/en/topics/001159.html.

2. Wagner, R., & Robinson, M. (n.d.). Distribution, formation mechanisms, and significance of lunar pits. Icarus, 237, 52–60. doi:10.1016/j.icarus.2014.04.002

3. Blair, David M.; et al. (January 15, 2017), "The structural stability of lunar lava tubes", Icarus, 282: 47–55, Bibcode:2017Icar..282...47B,

4. Lunar and Martian Lava Tube Exploration as Part of an Overall Scientific Survey

A White Paper submitted to the Planetary Sciences Decadal Survey 2013-2022 Lead Author: Andrew Daga Andrew Daga & Associates LLC, Malvern, PA USA Department of Space Studies, University of North Dakota, Grand Forks, ND USA

5. https://www.nasa.gov/sites/default/files/atoms/files/nationalspaceexplorationcampaign.pdf

6. LUNATUBE: A NEW MISSION DESIGN FOR LAVA TUBE EXPLORATION ON THE MOON. F.

Sauro1, Loredana Bessone2, Luca Parmitano2, Ian Carnelli3, 1Department of Biological, Geological and Envi-

ronmental Sciences, Italian Institute of Speleology, Bologna University, Via Zamboni 67, 40126, Bologna, Italy,

cescosauro@gmail.com, 2Directorate of Human and Robotics Exploration, European Space Agency, Linder

Höhe, 51147 Köln, Germany, loredana.bessone@esa.int, 3General Studies Program, European Space Agency, 8-

10 Rue Mario Nikis, 75738 Paris, France, ian.carnelli@esa.int.

(PDF) LunaTube: a new mission design for lava tube exploration on the Moon. Available from: https://www.researchgate.net/publication/316472865_LunaTube_a_new_mission_design_for_lava_tube_exploration_on_the_Moon [accessed Sep 24 2018].

7. MOON DIVER: A DISCOVERY MISSION CONCEPT FOR UNDERSTANDING THE HISTORY OF THE MARE BASALTS THROUGH THE EXPLORATION OF A LUNAR MARE PIT. L. Kerber1 , I. Nesnas1 , L. Keszthelyi2 , J.W. Head3 , B. Denevi4 , P.O. Hayne5 , K. Mitchell1 , J.W. Ashley1 , J.L. Whitten6 , A.M. Stickle4 , M. Paton1 , K. Donaldson-Hanna7 , R.C. Anderson1 , D. Needham8 , P. Isaacson3 , L. Jozwiak4 , 1 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA (kerber@jpl.nasa.gov), 2USGS Astrogeology Science Center, Flagstaff, AZ, 3DEEPS, Brown Univ. Providence, RI 02912. 4 Johns Hopkins Applied Physics Laboratory, Laurel MD 20723, USA, 5University of Colorado, Boulder, CO. 6CEPS, Smithsonian Institution, MRC 315, Washington, DC 20013, 7AOPD University of Oxford, UK, 8NASA Marshall SFC, Huntsville, AL..

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References

�8 “Technologies Enabling Exploration of Skylights, Lava Tubes and Caves NASA Innovative Advanced Concepts (NIAC) Phase I FOR OFFICE OF THE CHIEF TECHNOLOGIST NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANT NUMBER: NNX11AR42G AWARD DATE: SEPTEMBER 15, 2011 END DATE: SEPTEMBER 14, 2012 FINAL REPORT BY ASTROBOTIC TECHNOLOGY 4551 FORBES AVE #300 PITTSBURGH, PA 15213-3524 WILLIAM WHITTAKER, PRINCIPAL INVESTIGATOR.” url: https://www.nasa.gov/pdf/718393main_Whittaker_2011_PhI_Cave_Exploration.pdf

9. https://www.bostondynamics.com/sandflea

10. Aiko-Snake Robot with Electric Motors, www.sintef.no/en/digital/departments/applied-cybernetics/projects/our-snake-robots/aiko-snake-robot-with-electric-motors/.

11. Ackerman, Evan. “A Rocket-Propelled Miniature Robot for Planetary Exploration.” IEEE Spectrum: Technology, Engineering, and Science News, IEEE Spectrum, 6 June 2017, spectrum.ieee.org/automaton/robotics/space-robots/a-rocket-propelled-miniature-robot-for-planetary-exploration.

12. Reference: Dorrington, G. (n.d.). Rationale and concept for a lunar pit reconnaissance probe. Aeronautical Journal, 122(1250), 666–691. doi:10.1017/aer.2017.139

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Future Work

ESA Cave Exploration Program.
Many of these technologies can be and should demonstrated on earth analogues.

https://www.nasa.gov/pdf/637136main_Whittaker_Presentation.pdf

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Philolaus Crater:

Proposed by SETI’s Pascal Lee

Coordinates: 72.1degN, 32.4degW
550 km from North Pole
Good line sight for communication to earth

Credit: Lee, Pascal. “Philolaus Crater: Exploring Candidate Lava Tubes And Skylights Near The Lunar North Pole.” NASA, NASA, 2018, lunar-landing.arc.nasa.gov/LLW2018-43.

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Utilizing Commercial Lunar Payload Services

Credit: Astrobotic

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Vision of Future

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Utilizing Commercial Lunar Payload Services

Credit: Astrobotic

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How lava tubes form

https://www.fs.usda.gov/detailfull/coconino/learning/nature-science/?cid=stelprdb5275785

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Skylight to Lava Tube

Favre, G. Some observations of Hawaiian pit craters and relations with lava tubes, Proceedings of the 3rd International Symposium on Vulcanospeleology, 30 July–1 August 1982, International Speleological Foundation, Seattle, Washington, US, pp 37–41.

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Mission Architecture: Low Cost Probes

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Mission Architecture: Dedicated Robotic Mission

Credit: Reference 6

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Mission Architecture: Tethered Descent

Credit: Reference 8

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Mission Architecture: Low Cost Probe

Reference: Dorrington, G. (n.d.). Rationale and concept for a lunar pit reconnaissance probe. Aeronautical Journal, 122(1250), 666–691. doi:10.1017/aer.2017.139

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