Olympus base | Additive manufacturing NASA lunar framework

In Project Olympus, ICON and SEArch+ have developed design schematics for critical surface infrastructure necessary for a permanent lunar base. In 2020 ICON was awarded an SBIR contribution from Marshall Space Flight Center (MSFC) to contribute to NASA Marshall’s Moon-to-Mars Planetary Autonomous Construction Technologies (MMPACT) initiative. ICON will first demonstrate additive manufacturing capabilities for horizontal structures such as roads and landing pads, followed by demonstrations of vertical structures, including unpressurized radiation shelters as well as habitats. In 2020, ICON employed SEArch+ to develop design schematics for mission-critical surface construction elements for a lunar settlement, including concepts for surface-site deployment, construction sequencing, and structural design. The design process was informed by discussions with key ICON engineers and NASA collaborators. The exchange not only ensured the constructibility of designs according to hardware and material processing limitations but also enabled the architectural process to influence and shape hardware requirements as they were being defined. The ensuing habitat design, titled the “Lunar Lantern” for its double-protective outer shield structure, celebrates and promotes a design approach driven by human factors principles to ensure the safety and security of future crew. As a whole, Project Olympus envisions the construction of durable, self-maintaining, and resilient surface structures enabled by advanced 3D-printing technologies.

Employer: SEArch+ LLC

Client: ICON Technolocy Inc. / NASA

My job as a consultant for SEArch+ was to assess different strategies to deal with the dust ejecta during the landing sequence. Several environmental factors guide the design of a lunar landing and launch pad including but not limited to: temperature swings associated with day/night cycles, a site or location within permanently shadowed or permanently lit regions of the Moon, seismic activity, anticipated frequency of micrometeorite impacts, as well as materials degradation due to thermal swings. Traditional building methods of expansion joints and saw-style cuts may be valuable mitigation strategies to address thermal stress. The introduction of spaces between pavers to allow for expansion and contraction may relieve stress on 3D-printed surfaces and could also channel rocket plume and its associated ejecta toward a blast wall and dust trench. Additionally, using various patterns of alternating or layered contour and deposition tool paths may more reliably control materials failures in 3D-printed horizontal structures. Specifying alternating tooling patterns within a 3D-printed layup may improve strength properties and assist with understanding failure points.

Two design directions titled the “sunflower vault” and the “eyelashes” directions, were down-selected at the conclusion of an iterative concept phase. Both designs provide countermeasures to blast ejecta using different strategies. The sunflower vault uses a continuous printed circular wall to contain the ejecta, offering different rebound angles according to the different sizing of the regolith particles: the biggest ejecta will fly on a lower angle but at supersonic speed while the lighter, slower ejecta will fly at an higher angle. The circular wall is shaped in radial petal-vaults, designed to slow the regolith and collect it on the ground where it can be collected by an autonomous robot. Following wall completion, loose regolith may be dumped on the exterior ring to add structural integrity and penetration protection from the fastest ejecta particles. Three tunnels built radially around the landing area allow access to the pad. The three tunnels are oriented on the tangent angle with the internal wall circumference to limit the spread of regolith in the access paths.

The second proposed design, named “eyelashes” performs by absorbing ejecta. The aim of this concept is to force a high level of particle interactions and create a “cloud” of regolith that will exhaust the potential energy in intra-particle collisions. To achieve this objective, a ring will be excavated around the landing pad, after which a pattern of sintered regolith pillars will be constructed to stimulate the particle interaction in a specific area. The exhausted particles will sequentially fall into the collection ring. This direction may require less printing time, but will likely filter fewer particles compared with the sunflower vault option.

The above landing pad design investigations indicate that additional research is necessary to develop solutions that mitigate high-velocity dust impacts for a variety of lander types and lunar outpost configurations. The ejecta behavior is greatly influenced by the footprint of the landing vehicle and its mass; the speed of the particles as well as traveling angles thus have a high impact on landing pad design requirements.