As the space industry advances plans for missions to the moon, Mars, and beyond, construction professionals continue to develop innovative solutions for challenges both on Earth and in extraterrestrial settings. Building on knowledge gained from previous missions, along with ongoing research, the National Aeronautics and Space Administration (NASA) and various private teams are preparing to build habitable structures, mining operations, and other facilities in off-Earth locations.
This conceptual rendering of NASA’s mobile launcher 2 (ML2) and the Block 1B SLS rocket shows the scale and complexity of the ML2 design. Detailed renderings of the ML2 model are done separately at regular intervals. Image source: NASA. Click image to enlarge.
Technology Advances Launch Facility Upgrades
While much of the current research and development work is focused on how to build structures on the Moon and Mars, significant work is ongoing with upgrading Earth-based launch facilities to accommodate a new generation of heavier, more powerful rockets. NASA and its contractors are currently upgrading facilities at the Kennedy Space Center (KSC) in Florida in preparation for upcoming launches.
KSC’s Launch Pad 39B, which has supported numerous launches ranging from Apollo 10 in 1969 to Artemis I in 2022, has undergone a variety of upgrades for future missions. The first mobile launcher (ML1) used to launch Artemis I will also be used to launch Artemis II and Artemis III, currently scheduled for 2025 and 2026, respectively. For Artemis IV and future missions, NASA is building a replacement mobile launcher — ML2 — to launch rockets capable of carrying heavier cargo (see Part 1 article).
After completing a challenging jack and set operation earlier this year that moved the two-story ML2 base structure to a permanent mount structure, NASA and primary contractor, Bechtel National, Inc., are preparing to lift and set tower modules atop the base structure in the next few months. This requires ongoing monitoring of the structure weight as ML2 takes shape, according to Bechtel project manager, Paul Podolak.
“We’ve got to balance strength requirements with a weight that cannot exceed the crawler capacity,” Podolak said. The complexity of the structure has led to various design changes over the course of the project, requiring close monitoring of the ML2 structure weight. “We need to manage that through design, procurement, and construction,” added Podolak.
To accurately monitor weights, the team has installed scales on mount mechanisms, tracking changes in components such as cables and brackets that might have slightly different weights than initially assumed. As changes occur, computer models can be updated accordingly.
The team has also collected LiDAR data to help monitor construction. The simultaneous localization and mapping (SLAM) LiDAR scans enable the team to deliver a 3D model of the ML2 structure and surrounding area at any time during construction, according to Alex Beletic, Bechtel project field engineer. The team scans the site weekly to render 3D models that resident engineers and partners can access in real-time offsite.
“Because we’ve designed ML2 to remain within a safe margin of the NASA crawler-transporter’s load capacity, we’ll use our weekly SLAM LiDAR models to detail ML2’s build configuration when we take weight readings of the structure,” noted Beletic. “Over time, these 3D snapshots of the construction effort provide us a library of historical references of ML2’s status in a given week.”
SLAM LiDAR has been used to deliver 3D models of the ML2 structure and surrounding area at regular intervals during construction. Image source: Bechtel. Click image to enlarge.
Bechtel has used a variety of software tools during design and construction, such as Autodesk Navisworks for overall 3D model review and visualization, PTC Creo for detailed 3D modeling, PTC Windchill for product lifecycle management, Trimble Tekla for structural analysis, and Bentley Synchro 4D for depicting construction sequences. With the 4D modeling, “we can show how construction sequencing is going to work from the very beginning through construction and handover,” said Podolak.
Lunar Architecture
Meanwhile, other teams are developing designs for extraterrestrial structures. Under a $57-million contract with NASA, ICON Technology, Inc. is partnering with Danish architect Bjarke Ingels Group (BIG) to develop designs for landing pads, habitats, roads, and other facilities – initially for the lunar surface, and later for Mars.
Using ICON’s 3D printing technology and relying largely on native lunar materials, the team’s Project Olympus includes designs for toroid-shaped structures that offer several structural and functional benefits, according to BIG NYC partner Martin Voelkle. Due to the moon’s lack of atmosphere, minimal gravity, and other harsh conditions, structures must be designed for pressurization and resistance to extreme temperature variations, solar radiation, and meteorites. “Structurally, the torus shape is ideal for pressurization, while the cross section is optimized for 3D printing,” Voelkle noted. “Functionally, the torus allows for compartmentalization into independently pressurized zones with self-contained program elements and life support systems.”
A rendering of the Project Olympus lunar habitat depicts toroid-shaped structures. Image source: BIG. Click image to enlarge.
In another recent development, an international team of scientists discovered evidence of subsurface caves on the Moon, some of which could help shelter future astronauts. Based on observations from NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft, the team has identified more than 200 steep-walled pits that in some cases might lead to caves. Analysis indicates one cave might extend more than 200 feet from the base of a pit. LRO is managed by NASA's Goddard Space Flight Center in Maryland, and supported by various government, academic, and private partners. In a recent NASA publication, Robert Wagner, a research specialist at Arizona State University, said, “We’re currently in the very early design phases of a mission concept” to explore one of the pits.
Gateway to Mars
Looking beyond the Moon, NASA and partners have sights set on Mars. After the Artemis III mission, designed to send humans to explore the lunar South Pole region, NASA plans to send astronauts to the Gateway lunar space station via Artemis IV in 2028, providing opportunities for research and preparation for human missions to Mars. Gateway research includes studying solar and cosmic radiation, a chief concern for people and hardware traveling to Mars and other deep-space locations.
NASA is planning to launch and assemble initial elements of Gateway ahead of the Artemis IV mission, working in cooperation with the European Space Agency (ESA), Japan Aerospace Exploration Agency (JAXA), and private contractors, including Northrop Grumman and others. Smaller than the International Space Station (ISS) which has been orbiting Earth since 1998, Gateway will orbit the moon and measure approximately 20 meters long, less than one-fifth the length of the ISS. SpaceX is the first U.S. commercial provider slated to deliver cargo and other supplies to the lunar outpost.
The Gateway lunar space station will orbit the Moon, providing opportunities for research and preparation for human missions to Mars. Image source: NASA. Click image to enlarge.
Also guiding the path to Mars is the Moon-to-Mars Planetary Autonomous Construction Technology (MMPACT) project, which has been exploring how to develop infrastructure on the lunar surface via construction of landing pads, habitats, roadways, and other facilities. Technologies such as 3D printing and use of native materials are intended to be demonstrated on the Moon for future use on Mars.
Different Challenges
Missions to Mars will face a different set of challenges than lunar missions. Unlike the Moon, Mars has a thin atmosphere that provides some protection from radiation, extreme temperatures, and meteorites, according to BIG’s Voelkle. “Mars’ atmosphere is almost entirely made up of CO2 [carbon dioxide], which does not allow breathing but enables weather events such as storms,” Voelkle noted. “For the design, that means that while everything still needs to be pressurized, we can allow for less thick layers of insulation and the use of more vulnerable materials such as foils and fabrics.”
Mars may also offer more water and clay minerals that can be used as construction materials, noted Pete Carrato, a Bechtel fellow emeritus who now works as an independent consulting engineer. “On Mars, if you want to build something, there are geological formations similar to sedimentary formations on Earth,” he said. “The Moon has no sedimentary rock. To try to do masonry construction on the Moon would be difficult to impossible.”
Recent observations have also indicated significant amounts of sulfur in the Martian soil, which could be used to make waterless concrete. Molten sulfur would serve as the binder and other native Martian soil would serve as the aggregate material, based on research by NASA partners.
Gravity on Mars is 1/3 of Earth’s gravity, which is better for most construction operations than the Moon’s 1/6 gravity ratio. The day-night cycle on Mars is also similar to Earth’s, so “it would make sense to use the existing daylight cycle through openings in the structure,” noted Voelkle.
In a series of surface simulations at Johnson Space Center in Houston, NASA and partners are 3D-printing a BIG-designed Mars habitat to support long-duration, exploration-class space missions. Crews live in the Mars Dune Alpha for one-year missions, providing insight into space food systems and physical and behavioral health outcomes for future missions.
3D printing of Mars Dune Alpha simulation habitat at Johnson Space Center in Houston, Texas. Image source: BIG. Click image to enlarge.
BIG has also developed a prototypical design for a sustained Martian city for the United Arab Emirates. “[For that design,] we envisioned a structure that is a hybrid of concrete enclosures and pressurized domes with various levels of protection,” said Voelkle. Martian concrete would create the protected base of the habitat, and pressurized glass domes would form a habitable enclosure with natural daylight.
For its design work, BIG uses more than 40 different software tools, including primary BIM platforms Revit from Autodesk and Rhino3D from Robert McNeel & Associates (TLM, Inc.), along with custom plug-ins and scripts, according to Voelkle. Most in-house renderings are produced with Enscape from Chaos, along with Chaos’ Vray, Epic Games’ Twinmotion, and Dimension 5’s D5 Render. A variety of other simulation and computation tools are also used, along with AI for image enhancement.
Bridging the Gap
The off-Earth construction landscape is continually changing as new information is obtained and design concepts are tested. Earth-based research is often conducted as a precursor to further testing on the Moon, which can then lead to future missions to Mars and beyond.
Some experts view the journey to Mars as a leap-frog process that will require adjustments along the way. “The goal is to get to the Moon, then find resources available to get us to Mars,” said Patrick Suermann, interim dean of the School of Architecture at Texas A&M University, a key NASA research partner. “Much like the first moonshot, there are definitely some technological gaps that we’ll need to jump.”
And along with the technical challenges, political and environmental questions are emerging. Potential mining of resources in space offers numerous benefits, such as reducing the dependency on transporting materials from Earth for future missions and developing advanced technologies for both Earth and space applications. On the flip side, questions remain about ownership of off-Earth resources, environmental impacts, and related topics. In addition to the U.S., several other nations are eyeing the Moon and Mars as destinations, which makes space exploration a hot topic globally. The journey to building in space promises to be an interesting ride.
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