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HESE 12-Meter Lunar
Cut & Cover Structure

HESE 12-Meter Lunar Cut & Cover Structure

NASA’s Artimis Program’s goal is to establish permanent installations on the Moon, and following that, Mars.  The construction methods for the installations must employ minimal Earth materials because of the enormous transport costs.

Inflatable Space Habitats are the leading technology for quickly building permanent facilities on the Moon and Mars.  They provide large working and living spaces with relatively low transport requirements of mass and volume.  Inflatable Space Habitats are composed of strong multi-layered outer membranes.  They are transported in their collapsed state, and then expanded in use.  Examples of Inflatable Space Habitats include those from ILC Dover (ILC Dover, 2026).  Another example are the LIFE® Models from Sierra Space (SierraSpace.com, 2025), including the LIFE® 500 which provides 500 cubic meters of work space, equivalent to the work space provided by a 42 ft by 42 ft by 10-ft high warehouse. 

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Inflatable Space Habitats are in advanced development, and have been Space-tested.  For example, an Inflatable Space Habitat, developed by Bigelow Engineering, has been flown successfully as a storage appendage to the Space Station since 2022 (Bigelow Aerospace, 2025).

But Inflatable Space Habitats have two weaknesses:  they provide only low radiation protection for their inhabitants, and they cannot survive large momentum meteor impact.  These weaknesses are significant and inhibit their ability to serve as long-term places for humans to live and work on the Moon and Mars.

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A solution to these weaknesses is to protect the Inflatable Space Habitats underneath a cut & cover structure such as shown in the illustration.  Such cut & cover structures could be formed over trenches dug into the lunar or Martian surface, or by taking advantage of elongated craters created by glancing meteor impacts.  The problem is how to construct their roof beams.  This must be accomplished using minimal material from the Earth because of the enormous transportation costs.  HESE provides a solution.

 

HESE is a relatively new building technology.  It was discovered by a joint Army Research Team from the US Army Engineer Research and Development Center and the US Army Natick Soldier Center.  From 2007-2009 the Research Team investigated whether strong beams and columns could be made by placing a fill of frictional Mohr-Coulomb soil under compressive hydrostatic stress inside tubular fabric membranes.  Their objective was the development of construction methods that would require minimal material transport.  Such methods could be used by the Army to build fortifications in austere Earth regions that have minimal construction materials.

 

Frictional Mohr-Columb materials (Coulomb, 1776; Mohr, 1900) include many geologic materials that are abundant and widespread on Earth, such as sands, gravels and crushed rock.  They are believed to also be widespread and plentiful in lunar regolith (Mitchell et al., 1972) and Martian regolith (Oravec, et al., 2025).  Frictional Mohr-Coulomb materials have increased shear strength and stiffness when subjected to compressive hydrostatic stress.  For the Army experiments, tensile stresses within the membranes provided the compressive hydrostatic stress. The Army researchers termed these types of columns and beams “Hydrostatically Enabled Structural Elements” or HESEs.  During their investigation, the researchers conducted laboratory structural tests on HESE columns and beams.  The test results greatly exceeded the researchers’ expectations in terms of element stiffness and load-carrying abilities.  The results indicated that using HESE building elements, the Army could build protective fortifications in remote locations and would only need to transport the HESE membranes.  The local soils would be used as fill.  This would greatly reduce material transport requirements.

 

The Army researchers were awarded a U.S. Patent in 2012 (Welch, et al., 2012).  However, the research program changed direction at about this time and HESE research stopped.  HESE technology was never fully developed.

 

Planet Z Tech is continuing HESE technology development for use on the Earth, Moon, and Mars.  Planet Z has two patents pending associated with HESE design and fabrication methods.  These patents augment the original HESE patent.  We are teaming in the development program with both the Mississippi Polymer Institute of the University of Southern Mississippi, and the Mississippi State University Center for Advanced Vehicular Systems.

 

The HESE 12-Meter Lunar Cut & Cover Structure in the illustration was designed based on sub-scale laboratory results.  It uses HESE beams for roof support.  The Structure has a 1-m thick lunar regolith overburden for added protection of its contents.  It has an unsupported span of 12 meters by 12 meters.  The design criteria used was a maximum center deflection/span ratio.  The regolith was assumed to have the same density as a typical Earth soil of 1600 Kg/m3 (100 lb./ft3).  The roof loading took into account the Moon’s gravitational field of 1/6 that of Earth’s, the weight of the regolith overburden, and the weight of the HESE beams.  The designed HESE roof beams are 1.3 m (4.3 ft) in diameter.  They have internal hydrostatic stress of 100 psi (0.69 MPa).  The combined loading of the beams’ weight and overburden produced a maximum center deflection of 0.29 m (0.95 ft), or a deflection/span ratio of about 1/41, which is about 1/5 the maximum ratio seen in the HESE experiments.  It is well within the structural capabilities of the HESE beams.

 

The load represented by the regolith moving equipment during construction was also considered.  The equipment load assumed the mass, 30 kg (Earth weight 66 lb.), of the NASA IPEx Regolith Excavator (NASA IPEx, 2026) as loading at mid-span a single HESE roof beam.  The Moon’s 1/6 gravitational field reduces this load to 11 lbs.  The calculated deflection, 0.25 mm (0.01 inches), is negligible, showing the HESE 12-Meter Lunar Cut & Cover Structure would have no structural problems during the placement of the regolith overburden.

 

The design of the tubular membranes for the Structure requires high-strength fabric to withstand the combined internal pressure from the hydrostatic stress and the bending stress of the beams.  Suitable high-strength fabrics include Kevlar® or Vectran®.  These fabrics have extensive Space experience (e.g., Destefanis, et al., 2009).  Vectran® was used in the decelerating air bags for the Martian Exploration Rovers (Steltzner et al., 2003).  The Earth construction materials needed to build the HESE 12-Meter Lunar Structure on the Moon consists only of the HESE beam membranes.  The membranes’ total transport mass is 1,440 kg, and their total transport volume is 2.1 cubic meters.  These mass and volume payload requirements are well within the advertised design payloads of Blue Origin’s Blue Moon Mark 2 Lunar Lander (20,000kg; Blue Origin, 2026), and SpaceX’s HLS lunar lander (100,000 kg; Starship HLS, 2026). 

 

The 12 m by 12 m unsupported span would protect some of the largest of the Inflatable Space Habitats under development, such as the LIFE® 500 system of Sierra Space (SierraSpace.com, 2025).

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References:

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  1. Bigelow Aerospace, 2025.  Wikipedia Article accessed 5Jan2005. https://en.wikipedia.org/wiki/Bigelow_Aerospace

  2. Blue Origin, 2026. Blue Moon Mark 1. https://www.blueorigin.com/blue-moon/mark-1

  3. Coulomb, C. A., 1776. Essai sur une application des regles des maximis et minimis a quelquels problemesde statique relatifs, a la architecture. Mem. Acad. Roy. Div. Sav., vol. 7, pp. 343–387.

  4. Destefanis, R. et al., 2009. “Space Environment Characterisation of Kevlar® : Good for Bullets, Debris, and Radiation too,” 11th International Symposium on Materials in a Space Environment, 15-18 Sep 2009, Aix-en-Provence, France.

  5. ILC Dover, 2026. “Space Habitats.” ILC Dover website accessed 11Feb2026. https://www.ilcdoverastrospace.com/en/space-habitats/

  6. Mitchell et al., 1972. “Mechanical Properties of Lunar Soil: Density, Porosity, Cohesion, and Angle of Internal Friction,” Proceedings of the Third Lunar Science Conference, Vol. 3, PP. 3235-3253, M.I.T. Press, 1972. https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1972LPSC....3.3235M&defaultprint=YES&filetype=.pdf

  7. Mohr, O., 1900. “Welche Umstände bedingen die Elastizitätsgrenze und den Bruch eines Materials Civilingenieur.”

  8. NASA IPEx, 2026.  “Design and Testing of TRL5 IPEx Actuators.”  NASA Website accessed 11Feb2026. https://ntrs.nasa.gov/citations/20240012494

  9. Oravec, H.A., Asnani, V. M., Creager, C.M., Moreland, S.J., 2025. “Geotechnical Review of Existing Mars Soil Simulants for Surface Mobility,” https://ntrs.nasa.gov/api/citations/20200003046/downloads/20200003046.pdf

  10. SierraSpace.com, 2025. https://www.sierraspace.com/commercial-space-stations/life-space-habitat/

  11. Starship HLS, 2026. “Starship HLS” Wikipedia article accessed 10Feb2026. https://en.wikipedia.org/wiki/Starship_HLS

  12. Steltzner, A., Desai, P., Lee, W., Bruno, R., 2003. “The Mars Exploration Rovers Entry Descent and Landing and the Use of Aerodynamic Decelerators,” AIAA ADS Conference, May, 20-22, 2003.  Monterey, CA.

  13. Welch, C.R., Abraham, K., Ebeling, R.M., Quigley, C., Buehler, K., 2012. “Hydrostatically Enabled Structural Element.” U.S. Patent #8,209,911, issued 3 July 2012.

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