Accelerating the Lunar Economy: DARPA’s Vision and the Six Hypotheses for Revolutionary Advancements

The Moon, once a distant celestial body, is rapidly becoming the next frontier for human exploration and economic activity. The Defense Advanced Research Projects Agency (DARPA) is at the forefront of this lunar renaissance, with its LunA-10 program aiming to accelerate the development of a sustainable lunar economy.

The recent Request for Information (RFI) issued by the Defense Advanced Research Projects Agency (DARPA), is an ambitious step towards transforming the lunar landscape into a thriving economy. Titled “Six Hypotheses for Accelerating the Lunar Economy (SHALE),” this initiative aims to catalyze revolutionary advancements that could significantly propel the establishment of a commercial-driven lunar economy.

Background and Vision

DARPA’s vision for the lunar economy aligns with broader United States Government civil space goals, particularly those outlined in the National Cislunar Science & Technology Strategy (2022) and NASA’s Moon to Mars Infrastructure Objectives. DARPA envisions a future where lunar exploration and commerce are underpinned by a robust, integrated lunar infrastructure framework. This framework is intended to replace the current paradigm of isolated, self-sufficient lunar activities with a network of shareable, scalable systems capable of joint operation. An integrated framework would upend the current technical paradigm, whereby each lunar lander or activity must organically support all required resources for survival such as power, communications, and data storage.

In November 2023, DARPA launched the 10-Year Lunar Architecture (LunA-10) study, which explored the business and technical viability of non-terrestrial technologies aimed at creating a sustainable and monetizable lunar infrastructure.  LunA-10 focused on creating monetizable services for future lunar users in a mass-efficient manner, while complementing existing NASA and its international partners’ lunar investments.

From analysis performed under LunA-10, six areas of study have emerged as having potential for revolutionary breakthroughs that could enable a future commercial-driven lunar economy, which this RFI is centered around.

The Six Hypotheses for Accelerating the Lunar Economy

The study’s findings have identified six key areas of focus, which DARPA believes hold the potential for revolutionary breakthroughs that could directly accelerate the development of a lunar economy. DARPA’s SHALE initiative focuses on six critical areas where disruptive advancements could drive the rapid fielding of a commercial-driven lunar economy. These areas are:

1. Centralized Thermal Rejection and Generation as a Service
2. Widespread Orbital Lunar Prospecting and Surveying
3. Creating Large Silicon Wafers for Microsystems on the Moon
4. Biomanufacturing to Accelerate Lunar Construction
5. New Concepts to Increase Refinement Rates in Low Gravity
6. New Concepts for Lunar Position, Navigation, and Timing

Each of these focus areas represents a distinct challenge in lunar exploration and infrastructure development. DARPA is seeking actionable technical insights and innovative methods that can deliver order-of-magnitude improvements over the current state-of-the-art in these areas.

1. Centralized Thermal Rejection and Generation as a Service

The lunar environment presents extreme thermal challenges, with significant temperature fluctuations between the lunar day and night. Current lunar systems must include mechanisms for both thermal rejection (during the lunar day) and thermal generation (for lunar night survival), leading to heavy, mass-inefficient systems.

For instance, the mass required for thermal systems can constitute up to 60% of the total system mass in optical-wavelength power beaming systems, 45% in In-Situ Resource Utilization (ISRU) plants, and 25% in surface fission plants. Proton exchange membrane fuel cells (PEMFCs) can generate up to 45% of their output as heat, while thermoelectric devices like radioisotope thermoelectric generators (RTGs) exhibit electrical conversion efficiencies between 5% and 20%, with the potential to produce continuous heat levels as high as 4-5 kWt from 300 W of generated electrical power. The hardware required to reject this waste heat significantly impacts the overall mass efficiency of systems relying on RTGs or PEMFCs for power generation.

DARPA’s hypothesis is that by centralizing thermal rejection and generation into a single hub, similar to a commercial building’s HVAC system, mass efficiency could be drastically improved. This would allow lunar users to offload their thermal needs to a centralized service, reducing the mass and cost of individual systems. DARPA seeks innovative methods to enhance thermal rejection and storage per unit mass, and explore the feasibility of extracting electrical energy from excess heat.

A future thermal hub is envisioned to work analogously to a heating, ventilation and air conditioning (HVAC) system in a commercial building. Each floor in a commercial building might have its own heating or cooling requirements, but all are managed by a single building-wide HVAC unit. The centralized thermal rejection/generation hub would establish connections to an arbitrary number of nearby users – during the lunar day, the hub would push cooling fluid and use its heat pumps to draw heat away from users, and during the lunar night,
release stored or generated heat to those same users for survival needs.

2. Widespread Orbital Lunar Prospecting and Surveying

The potential of the lunar economy is closely tied to the resources available on the Moon. However, the distribution and accessibility of these resources, particularly at the subsurface level, remain largely unknown.

Current knowledge points to water and oxygen extractable from cold traps close to the lunar poles, but other resources, to include those that may be present beneath the top meter of lunar regolith, are unknown. Data of sufficient fidelity are not available to understand the distribution of resources across the Moon at the near sub-surface level (defined as the top 3-10 meters of the Moon). Once those areas are identified, then reserves of economically recoverable material could be evaluated for mining and processing operations, and galvanize the economics behind a future lunar economy

DARPA aims to revolutionize lunar resource prospecting by enabling low-altitude orbital campaigns that can perform detailed surveys and identify resource-rich areas. FA2 aims to explore highly innovative methods for dramatically improving low-altitude orbital station-keeping and maneuvering to enable comprehensive coverage of the lunar surface. This involves a comparative analysis with current state-of-the-art technologies to highlight the challenging advancements sought. Additionally, FA2 seeks to identify the most effective sensing modalities for prospecting and surveying activities and develop a comprehensive system capable of rapidly capturing, disseminating, and processing large data sets. The focus is also on determining the relevant data accuracy required to justify further prospecting efforts and specifying the sensing modalities and resolution necessary for a photogrammetry mission on the lunar surface. Furthermore, FA2 will address anticipated technical difficulties associated with implementing potential solutions.

The ability to maneuver at very low altitudes with minimal propellant consumption, combined with advanced sensing modalities, could provide the high-fidelity data needed to unlock the commercial value of lunar resources.

3. Creating Large Silicon Wafers for Microsystems on the Moon

Silicon wafers are fundamental to modern technology, and the unique conditions of the lunar environment offer an opportunity to produce larger and higher-quality wafers than is possible on Earth. The reduced gravity on the Moon could facilitate the growth of larger, more uniform crystals, paving the way for advanced microsystems and semiconductors that are essential for a post-Moore’s law future.

Crystals grown in microgravity (0 g) exhibit significant improvements over those produced on Earth, including up to 60% larger sizes, up to 75% higher quality, and up to 80% more uniformity. A comprehensive literature review reveals that 90% of crystals grown in microgravity show enhancements in size, structure, uniformity, resolution limit, and mosaicity. These advancements can be harnessed through in-space manufacturing to develop growth systems for silicon wafers and, eventually, commercial-scale wide bandgap and ultra-wide bandgap semiconductors of unparalleled size and quality. In a microgravity environment, the absence of hydrostatic pressure eliminates the need for gas flow systems or infrastructure to support liquid melts, while the lack of thermal convection prevents inhomogeneous composition defects, leading to superior crystal properties.

Nonetheless, manufacturing in zero-gravity presents complex challenges, as some level of gravity can be beneficial for certain processes. The Moon, with its 1/6g environment, may offer an optimal compromise by combining the advantages of low gravity with minimally modified, gravity-fed processes that are more compatible with Earth-based methods. This lunar environment could enable advancements beyond Moore’s Law and address critical needs for silicon-based microsystems, which are essential to modern technological infrastructure on Earth.

DARPA is interested in exploring the feasibility of manufacturing large silicon wafers on the Moon, including the potential integration with other in-situ resource utilization (ISRU) processes. FA3 seeks to explore the feasibility of manufacturing large silicon wafers (greater than 400 mm) on the lunar surface. Key considerations include identifying innovative methods for lunar-based silicon wafer production and comparing these methods to state-of-the-art techniques to highlight the advanced nature of the proposed solutions. This involves understanding the specific hardware required for microgravity crystal growth and the primary processes needed to achieve high-quality lunar-manufactured silicon wafers, including power and thermal supply assumptions.

Additionally, it is essential to evaluate the potential for co-designing silicon wafer manufacturing with ISRU (In-Situ Resource Utilization) plants, which may operate at temperatures around 1425°C—similar to those used for carbothermal reduction of lunar regolith. This includes examining the use of pure silicon from Earth, purified lunar regolith, or utilizing waste heat from other processes. The analysis should also compare the advantages of lunar manufacturing in terms of wafer size, purity, structure, and uniformity with those achieved in microgravity and Earth gravity environments. Understanding the growth speed and defect rates of lunar-manufactured silicon wafers compared to those produced on Earth will be critical, along with developing complementary modeling and simulation capabilities to validate feasibility and addressing anticipated technical challenges, particularly in terms of system efficiency and production rates.

4. Biomanufacturing to Accelerate Lunar Construction

Biomanufacturing offers a promising approach to creating materials and structures on the Moon using locally available resources, such as lunar regolith. This approach could be key to establishing a sustainable lunar presence by reducing the need for resupply missions from Earth.

Microbial biomanufacturing offers a transformative approach for developing integrated solutions in remote or austere environments, particularly in space settings. Unlike traditional mechanical or chemical methods, biotechnologies leverage microorganisms to enable sustainable, long-term operations. By utilizing local resources and focusing on closed-loop systems, this approach not only enhances efficiency but also addresses the ethical and practical challenges of space waste management. The recycling and reuse of materials, central to a circular economy, minimize the need for costly resupply missions from Earth and support environmental preservation.

In-space biomanufacturing is increasingly seen as a viable strategy for producing bioenabled structures from lunar regolith, creating industrial fuels and lubricants from Earth-sourced materials, and even biomining rare earth elements in trace amounts. This approach is particularly promising for developing modular, autonomous systems that can operate within closed-loop lunar environments. FA4 seeks to explore the feasibility of these advanced biomanufacturing techniques, focusing on their potential to establish sustainable, self-sufficient systems on the Moon and their impact on space resource management.

DARPA is seeking innovative biomanufacturing methods that can produce construction materials, pharmaceuticals, fuels, and other essential products in a closed-loop system. This could include using engineered microorganisms to convert lunar materials into usable products, potentially transforming waste streams into valuable resources.

5. New Concepts to Increase Refinement Rates in Low Gravity

The refinement of lunar resources is essential for the development of a self-sustaining lunar economy. However, the low-gravity environment of the Moon presents unique challenges for traditional refining processes.

Several elements found on the lunar surface and asteroids hold substantial economic promise, yet their trace concentrations often render extraction impractical with current technologies. For instance, the Procellarum KREEP terrane on the Moon contains uranium and thorium at concentrations of just 2 ppm and 7-10 ppm, respectively, which are too low for efficient extraction. In contrast, Platinum Group Metals (PGMs) on asteroids, with concentrations ranging from 100 to 250 ppm, present a more viable extraction scenario. However, even with these higher concentrations, the cost of launching and returning substantial quantities to Earth makes the endeavor economically challenging. For economic feasibility, a mission would need to return at least one metric ton of material, requiring the processing of around 4 million kilograms of raw material—an arduous task in the low-gravity environments of the Moon or asteroids and a process that could span approximately a decade with current technologies.

FA5 is focused on identifying innovative mining methods and system designs that can significantly enhance the throughput, beneficiation, and refinement of regolith, whether lunar or asteroidal, for extracting elements present in concentrations less than 100 ppm. Specifically, FA5 seeks solutions that can achieve mining and refining rates substantially greater than the current benchmark of 3 kg/minute per watt of power provided. This includes exploring novel approaches to increase efficiency in both extraction and processing to make the exploitation of these low-abundance resources economically viable.

DARPA is looking for new concepts that can increase the efficiency of resource refinement in low gravity, potentially leveraging novel physical, chemical, or biological processes. These advancements could significantly reduce the time and energy required to process lunar materials, making resource extraction and utilization more economically viable.

6. New Concepts for Lunar Position, Navigation, and Timing

As lunar activities expand, reliable position, navigation, and timing (PNT) systems will be crucial for ensuring safe and efficient operations. Current PNT solutions designed for Earth may not be directly applicable to the lunar environment, where factors such as signal delay, interference, and lunar surface conditions pose significant challenges.

If one were to design the Global Positioning System (GPS) today, the choice between a space-based system and a ground-based system with localized corrections would be influenced by the specific requirements of the environment. Space-based systems, like the current GPS, provide global coverage, which is crucial for remote areas that lack dense population centers. However, for lunar commercial activities, which are expected to be concentrated in a few resource-rich regions, the extensive global coverage provided by space-based systems may be unnecessary. The Moon’s environment, with its limited operational areas, suggests that an Earth-like GPS approach might not be the most efficient solution for lunar navigation and positioning.

FA6 seeks to explore radically innovative concepts for Positioning, Navigation, and Timing (PNT) systems tailored specifically to the lunar domain. The focus is on developing new methodologies that address the unique challenges and constraints of the lunar surface, potentially involving localized solutions that could be more practical and cost-effective than the traditional global systems used on Earth.

Exploring very low-power solutions for generating, maintaining, and sharing timing signals on the Moon presents unique challenges. The aim is to develop systems that operate independently of Earth-based signals, ensuring reliable timing and synchronization in the lunar environment. These solutions must also address the need for extremely low Size, Weight, and Power (SWaP) concepts to support position and navigation on the lunar surface with approximately 10-meter accuracy, even when out of line-of-sight of orbital or ground-based assets.

Innovative methods are needed to share, update, and synchronize Positioning, Navigation, and Timing (PNT) signals among mobile users who may be beyond each other’s line of sight. For example, utilizing low-frequency radio waves for data transmission via ground waves could offer a potential solution. Additionally, understanding the specific requirements for lunar PNT in the context of near-future commercial operations is crucial. The focus is on identifying and overcoming technical difficulties while excluding solutions reliant on direct Earth-based PNT, NASA LunaNet, Earth-like multi-satellite constellations, or relay schemes.

DARPA is interested in new PNT concepts that can provide accurate and reliable data for lunar missions, potentially leveraging new technologies or adapting existing ones for the unique conditions of the Moon.

Conclusion

The SHALE initiative represents a bold step towards realizing a future where the Moon is not just a destination for exploration, but a hub of economic activity. By focusing on key areas with the potential for revolutionary breakthroughs, DARPA aims to accelerate the development of a commercial-driven lunar economy that could benefit the United States, its allies, and the global space community.