The Lunar Stairway: An Orbital-Platform-First Paradigm for Lunar Development and Its Engineering Rationale
This paper argues that establishing a distributed network of circumlunar orbital platforms, termed the "Lunar Stairway," is an engineering superior alternative to surface-based lunar development due to significant advantages in energy efficiency, safety from seismic and radiation hazards, environmental stability, and logistics capabilities, while utilizing ballistic delivery systems to maintain a functional connection with the lunar surface.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For decades, the dream of living on the Moon has been visualized as a colony of domes and habitats resting directly on the dusty, gray surface. This vision assumes that to build a future there, humanity must first conquer the difficult, dangerous task of landing heavy machinery and people safely on the ground. The prevailing strategy involves building permanent bases on the lunar soil, treating the surface as the primary stage for all future activity. However, this approach faces a fundamental physical hurdle: the Moon lacks an atmosphere to slow down falling objects, meaning every piece of cargo must carry enough fuel to fire its engines and brake itself to a gentle stop. Once there, it must also carry enough fuel to take off again if it ever needs to leave. This cycle of landing and taking off consumes a massive amount of energy and requires complex, fragile machinery that has failed roughly half the time in history.
A new perspective challenges this surface-first mindset by proposing that the true foundation of lunar development should be built in the space surrounding the Moon, not on the ground itself. This concept, termed the "Lunar Stairway," envisions a network of large, rotating stations orbiting the Moon, acting as a floating harbor for people, factories, and supplies. Instead of landing everything directly, these orbital platforms would act as a transfer point, dropping materials toward the surface using a controlled, high-speed delivery system that relies on the Moon's own gravity and massive, pre-built cushioning systems on the ground to stop the cargo. This approach shifts the heavy engineering burden from the fragile, high-risk act of landing a spacecraft to the more manageable task of building a permanent, reusable receiving infrastructure on the lunar surface.
The paper argues that staying in orbit is not just a temporary stopover but a superior long-term strategy for human presence. The author calculated that the energy required to land on the Moon and then take off again is so high that it consumes nearly three-quarters of a spacecraft's total mass in fuel. In contrast, keeping a station in a stable orbit requires very little fuel to maintain its position, especially if the station uses efficient electric thrusters. The data shows that maintaining a low orbit around the Moon costs about the same amount of fuel per ton of mass as keeping a station in orbit around the Earth, a feat humanity has mastered for decades. By moving the center of human activity to this orbital ring, the need for constant, expensive, and risky landings is drastically reduced.
The risks of living on the surface are another major factor driving this proposal. The lunar ground is a harsh environment where dust behaves like tiny, sharp shards of glass that cling to everything due to static electricity, damaging equipment and harming human lungs. The surface is also exposed to unfiltered radiation from the sun and deep space, and it is subject to "moonquakes" that can last for hours, shaking structures far longer than earthquakes on Earth. An orbital platform avoids these problems entirely. It is free from the abrasive dust, can maneuver to avoid meteoroid impacts, and can use the Moon itself as a shield against radiation when necessary. Furthermore, an orbital station offers a much better view of the universe, free from the horizon limits and dust interference that plague telescopes on the ground.
The core of the "Lunar Stairway" system is a method of delivering cargo from the sky to the ground without using expensive landing engines. The process begins with a cargo container being ejected from an orbital platform. Instead of firing engines to slow down, the container is simply dropped, allowing it to fall freely toward a pre-selected crater on the Moon. As it falls, it accelerates to high speeds, reaching about 1.7 kilometers per second by the time it hits the ground. To stop this fast-moving object without destroying it, the plan relies on a "sponge lake" built inside a lunar crater. This facility would consist of layers of energy-absorbing materials, such as specialized foams, airbags, and nets, designed to crush and dissipate the impact energy over a long distance. The author suggests that by increasing the surface area of the falling cargo—perhaps by wrapping it in a large, parachute-like airbag—the force of the impact can be spread out enough to allow even heavy tonne-scale cargo to land safely.
This system creates a continuous loop of logistics. While cargo falls from the platform to the surface, materials mined on the Moon could be shot back up to the platform using electromagnetic launchers, which use electricity rather than chemical fuel to accelerate payloads. This exchange allows the orbital station to maintain its position without needing to burn large amounts of fuel. The momentum of the falling cargo and the rising cargo can balance each other out, keeping the station stable in its orbit. The paper also proposes a novel way to handle the metal hulls of spacecraft that arrive from Earth. Instead of returning these heavy steel shells to Earth, which wastes fuel, they could be left in orbit to serve as a reserve of raw metal, ready to be used for future construction or as shielding for the stations.
The author acknowledges that this system requires significant upfront investment in building the receiving facilities on the Moon and the orbital platforms themselves. They performed a detailed analysis to find the point where this method becomes cheaper than traditional landing methods. Their calculations suggest that once the total amount of cargo delivered reaches a certain threshold—roughly a few hundred tonnes—the savings in fuel and the elimination of landing failures make the orbital approach the more economical choice. For small, one-off missions, traditional landing might still be better, but for the large-scale, continuous development needed to build a lasting lunar presence, the orbital platform offers a sustainable path.
The paper outlines a phased timeline for bringing this vision to life, starting with small-scale tests to verify that the "sponge lake" can safely stop falling objects and that the orbital mechanics work as predicted. If these initial steps succeed, the next phase would involve building the first permanent orbital ports and establishing a routine flow of materials between the sky and the surface. This would eventually lead to a network of stations capable of supporting human life, manufacturing, and scientific research, with the lunar surface serving as a resource hub rather than the primary home for humanity. The ultimate goal is to create a system where the Moon is not a destination to be conquered by landing, but a neighborhood to be inhabited from the sky, with the surface acting as a convenient, accessible workshop below.
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