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Lunar Starship
SpaceX’s Starship could be useful not just for transporting cargo to the Moon but also for providing infrastructure. (credit: SpaceX)

SpaceX Starship in lunar development

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The November 18 test flight of Elon Musk’s Starship that was launched from Boca Chica on the Texas Gulf Coast suggests the day is ever closer this mega-rocket, in its future iterations, will be available for missions to the Moon. Already selected by NASA for the Human Landing System (HLS) program, the lunar variant of the Starship will open up the Moon to both exploration and industrialization. That said, even SpaceX itself may not yet recognize the extent to which Starship will revolutionize lunar surface operations.

Ever since the 1990s I have been exploring and analyzing business models for lunar economic development and two basic problems have always emerged:

  1. The inability of launch providers to send cargo to the Moon in the necessary quantities and at a cost economically viable for both exploration and industrialization.
  2. The challenge of remotely building facilities on the lunar surface.

The lunar variant of the Starship promises to solve such problems as well as others that logically present themselves in any pioneering endeavor.

Already selected by NASA for the HLS program, the lunar variant of the Starship will open up the Moon to both exploration and industrialization.

The HLS variant of the Starship is designed to deliver large payloads cheaply to the lunar surface. More significantly, SpaceX’s mega-rocket is sufficiently powerful to carry even full-size mining and construction equipment intact: such cargo weighs from 40 to 60 tons on Earth. Equipment of that size range is critical for establishing the infrastructure crucial for economic development of the Moon and its quintessential commerce. Even more vital to lunar development is that Starship variants will enable constructing facilities to promote rapid growth of an economy on this resource-rich natural satellite.

So far, business models for lunar development suggest the traffic flowing between the Earth and the Moon will be unbalanced if one considers the amount of mass sent to the Moon from the Earth is greater than the mass returning to our home planet. Assuming that the SpaceX Starship will serve the vast majority of lunar logistic needs, as many as nine out of ten Starships under some scenarios will logically be returning empty to the Earth, a massive waste of fuel and resources. Abandoning such rockets on the Moon would also be wasteful. Instead of Starships returning to the Earth empty, is it not more cost-effective, creative, and dynamic to modify them for use as permanent facilities and integrate them into the lunar infrastructure?

A review of the requirements for such infrastructure means we need two variants of these one- way lunar Starships. The first will be a version of the HLS designed to create permanent facilities on the lunar surface. In this variant, the interior of the cargo section is reconfigured during its construction to serve as a horizonal lunar habitat, vehicle service facility, lunar agriculture facility, or for some other purpose. The estimated pressurized volume of 1,000 cubic meters is as large as the pressurized volume of the ISS. Once on the Moon and after the cargo has been unloaded, the cargo section can be separated from the tankage section of the HLS Starship by a mobile crane brought to the Moon on an earlier flight. The cargo portion of the Starship is then placed on a lunar version of the crawler SpaceX uses at Boca Chica to transport the Starship. On the Moon this lunar crawler will deliver the cargo section to a predetermined location at the facility where the mobile crane will lower the cargo section horizontally onto the Moon’s surface, to either stand alone or be connected to other HLS cargo sections. Once in place, the cargo section will be covered with lunar regolith to shield it from radiation and micrometeorites.

Instead of Starships returning to the Earth empty, is it not more cost-effective, creative, and dynamic to modify them for use as permanent facilities and integrate them into the lunar infrastructure?

The lower section of this HLS Starship, which contains the fuel tanks, will then have its Raptor engines removed for shipment to Earth to be reused on future Starships. After the Raptors are removed, the HLS lower section is transported to a suitable location to be repurposed as part of a storage tank farm for the facility. Once in the desired location, this HLS lower section is either placed horizontally and covered with regolith to insulate the fuel tanks from the Sun or remains upright. If remaining upright, a canopy can be erected over the HLS lower section to shield the tankage from direct sunlight to reduce the boiloff of the cryogenic liquids stored within the tankage unit. The lower gravity of the Moon will make such construction and manipulation much easier than on Earth. In this way, instead of wasting these surplus lunar Starships they are put to productive use to create habitats, lunar farms, or other components of a successful infrastructure.

The second variant of the one-way lunar Starship is based on the tanker variant designed to service the fuel depots in Earth orbit. Lunar facilities will need a large mass of volatiles to support their operations, especially if those include agriculture and industrial activities. The primary volatiles required are hydrogen, methane, nitrogen, and water. Hydrogen is used for fuel or to produce water through combination with oxygen that is generated from the lunar regolith. Methane is used for fuel serving the Starships that return to Earth. Nitrogen is as fundamental to agriculture on the Moon as it is on Earth and also has many industrial applications. If there is no source of water near the lunar facilities, water can also be transported to the Moon by these tanker Starships to meet the needs of lunar development. The lunar variant of the tanker Starship will be modified to make the one-way trip by removing the heat shield titles and steering fins, reducing its launch mass. This choice also increases the potential payload delivered to the lunar surface. Once on the Moon, the tanker Starship and its payload of volatiles will be integrated into the lunar facilities’ tank farm. Once transferred to the tank farm, the Starship’s Raptor engines and any unnecessary flight control systems would be removed for eventual return to the Earth and used on future Starship missions.

There are several reasons why Starship-derived lunar facilities should significantly lower the cost of creating infrastructure. First, most of the labor for constructing lunar facilities will take place on the Earth rather than on the Moon itself. Second, SpaceX can mass produce Starships on an assembly line. Therefore, the costs of the one-way Starships will in all probability be far lower than other options for building infrastructures on the Moon. Finally, the Starship-based components—the building blocks of lunar facilities—could be fully outfitted and tested on Earth before launch, making them available for occupation by astronauts or used as storage tanks within days after delivery on the Moon.

The use of the Starship to create facilities on the Moon will put lunar commerce on the fast track and accelerate the emergence of a lunar economy.

It follows that lunar facilities constructed from Starship spacecraft could generate additional revenue for SpaceX. One approach would be for the rocket company to rapidly recover the costs of their construction by selling the facilities to commercial companies or governments. Another option is that SpaceX would retain ownership of the lunar facilities yet lease them to customers, thereby creating an ongoing revenue stream with SpaceX operating as a lunar landlord. In yet another approach the company retains ownership of the Starship-derived storage tanks and simply charges for the volatiles used on a per-kilogram basis. Moreover, SpaceX could conceivably partner with other corporations in joint ownership of some of the lunar facilities it created. Most likely, SpaceX will employ a combination of these revenue strategies based on the needs of the market for lunar facilities.

This proposed strategy for using surplus Starships as infrastructure will make full use of the potential of the Starship both as a transportation system and for the rapid creation of infrastructure. The use of the Starship to create facilities on the Moon will put lunar commerce on the fast track and accelerate the emergence of a lunar economy. The facilities Starship creates by repurposing surplus spacecraft will save years of labor in the early infrastructure and industrialization of the Moon. Strategies to utilize these aspects of the Starship as a motherlode for construction could also work on Mars quite as effectively. If Starship missions as cargo transport and one-way rockets are recycled as components to build infrastructure, such innovation accelerates the human settlement of the solar system by years.

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