Swiss company Astrostrom GMBH, headed by astronautical artist and researcher Arthur R. Woods, has presented an ambitious and extensive plan to provide power from space. The company’s report, running a lengthy 269 pages, details its vision of a grand, decades-long project to create a constellation of satellites that would beam free renewable power to Earth, with solar cells and infrastructure materials largely mined and refined from lunar regolith.
Published in SPACEREF: August 15, 2023 by Craig Bamford
Link to article:
https://spaceref.com/newspace-and-tech/astrostrom-releases-extensive-plan-space-based-power-built-lunar-resources/
The report was written in response to a European Space Agency (ESA) research challenge made in July of this year. The challenge was part of its SOLARIS initiative, which was “inviting researchers to help advance our knowledge of key aspects of collecting solar power in space and wirelessly transmitting it to Earth.” As the ESA notes, traditional, ground-based solar power’s effectiveness is significantly affected by the atmosphere, clouds, and the day/night cycle—to which you could add seasonal variations in much of both the United States and Europe—so collecting power in space using Space Power Satellites (SPS) orbiting high above any cloud cover and beaming it to Earth is a tempting idea. This is a particularly pressing issue for Europe, which aims to become carbon-neutral by 2050, but has a number of member nations that are unlikely to embrace nuclear power and may not be able to rely on renewables for baseline power.
However, it’s also a daunting challenge. As Astrostrom noted in the (still-extensive) executive summary of its report, it would face “the enormous logistical effort needed to launch the many gigawatt-scale SPSs from the surface of Earth into geostationary orbit.” This would require thousands of launches. Europe doesn’t have that kind of capability, and even if SpaceX succeeds in all their plans for building a fleet of Starships capable of repeated launches, Astrostrom estimated that it “would require 362 Starship launches per SPS or 9,050 Starship launches for 25 SPSs.” 9,000 Starship launches for one project seems impractical, even for something as groundbreaking as space-based power, and far exceeds the number of successful launches in human history.
Astrostrom’s study, which it named “GE⊕-LPS,” proposes a different solution. Astrostrom advocates “manufacturing a substantial portion of the SPSs from lunar materials and robotically assembling these in lunar orbit.” So instead of assembling the satellites on Earth—or even manufacturing their parts—the materials will be acquired on the Moon, processed there, sent into lunar orbit, then used for manufacturing the space power satellites which will be moved down to Geosynchronous orbit. This process is generally referred to as in situ resource utilization (ISRU).
For the GE⊕-LPS satellites, Astrostrom proposed the use of monograin layer (MGL) single-crystalline solar cells in a 3-dimensional “butterfly” shape. The MGL solar cells are a type of solar cell based on a microcrystalline powder developed by scientists at Estonia’s Tallinn University of Technology. A key component for the solar cells would be pyrite. Pyrite can be processed from troilite, which makes up over 1 percent of lunar regolith, so it is comparatively plentiful on the Moon and, the report says, comparatively easy to acquire. The solar panels wouldn’t be as efficient as traditional silicon, but Astrostrom believes that it wouldn’t be a problem because it can make up for the deficit by building larger panels than would be practical on Earth.
The “butterfly” shape, with helix-based wings that form a “V” shape from the satellite’s center, is designed to be able to generate power from any direction, “no matter how the inclination to the sun changes,” the report says, while also staying out of the way of the beamforming antenna that would send power to Earth.
Lunar assembly lines
Astrostrom’s proposal emphasizes relying on Lunar ISRU wherever possible, taking advantage of the comparative ease of transporting lunar materials into space. The company envisions lunar production facilities dedicated to producing enormous rolls of pyrite to be turned into power-beaming satellites, moving at up to 600 meters per minute.
Basalt fibers and cast basalt, easily made from lunar regolith, could be used in everything from the structural components of the power satellites to the manufacturing infrastructure, to components on the power antennas. In its report, Astrostrom points to studies suggesting that “[basalt] fibers produced in the lunar environment … may have better mechanical properties than basalt fibers produced on Earth.” The ESA’s Advanced Concepts Team also notes that lunar basalt fiber has “high strength and high modulus with excellent shock resistance,” along with comparative ease of production.
Aside from the pyrite and basalt, ilmenite (also found in lunar regolith) could be used for semiconductors, along with elements found in regolith like aluminum, titanium, and silicon.
But not all of the materials can be gathered on the Moon. Some materials for the satellites or their production facilities would need to be brought from Earth, especially during early ramp-up and experimental phases. There’s also still research to be done on the materials and various manufacturing processes, especially regarding the MGL panels and perfecting the basalt fibers. But Astrostrom believes it is achievable using current scientific and engineering techniques, and concludes that intensive use of lunar ISRU is key to making the project efficient and profitable.
Orbital manufacturing and a lunar space elevator
The project would also require a vast logistical setup and some yet-undeveloped technology in order to handle the ferrying of materials and components to and from orbit. For example, Astrostrom said that actual satellite and infrastructure manufacturing wouldn’t happen on the Moon. Instead, it would happen at the main operations hub, which would be a space station at or near the EM-L1 Lagrange point. The manufacturing would be robotic, but Astrostrom envisions the satellite as a crewed hub for both satellite manufacturing and transferring supplies within cislunar space.
Astrostrom also envisions that the hub could eventually be connected to the Moon via a space elevator. While a terrestrial space elevator is still very much distant science fiction, Astrostrom believes that it is a workable project on the Moon, even using current materials, owing to the lower gravity and lack of significant atmosphere. The company acknowledges that the terrestrial side will still require a crew-ready European reusable heavy-lift launcher, which may be a significant barrier, meaning the project would need to rely on American launch companies. It will also need a cislunar cargo shuttle.
While appearing expensive, GE⊕-LPS could ultimately end up saving Europe an enormous amount of money. Astrostrom projects that the infrastructure investment involved in getting all this working would “cost less than €100 billion” ($109.2 billion), which is a tiny fraction of the European energy transition budget of 5 trillion Euros. Astrostrom estimated that, when finished, electricity from the lunar-sourced satellites would be significantly cheaper than terrestrially-made ones, costing €74/MWh ($80.1) compared to €156/MWh ($170.5). With 78 power sats, Astrostrom estimates “a potential net profit of approximately €1.4 trillion over a 30-year period”, providing 886 TWh of clean baseload electricity per year.
Whether any of this will come to pass is unclear; putting technological hurdles aside, Astrostrom claims that “the geopolitical challenges may be the most difficult to overcome.” The report says that the Ukraine conflict has highlighted the importance of fossil fuel control in geopolitical conflict, and that any energy-focused project this size is going to have a huge geopolitical impact. The company grants that “international legal cooperative arrangements and agreements will be a prerequisite for its eventual success, and that the satellites and hub will be politically or physically vulnerable if “only one nation or even if a small group of politically aligned nations takes the initiative.” While it may be unlikely that this particular proposal is brought to life, it does demonstrate the possibilities that come with expansion into cislunar space, the return to the Moon, and the exploitation of Lunar ISRU.
Nevertheless, assuming there’s political will, Astrostrom does provide a timeline and set of milestones. This includes early R&D and organizing over the next few years, ramping up in 2025-2026. The efforts to build the project begin in earnest starting in 2027, scaling up over the next decade. The first power satellites would be produced in 2037, with the constellation up and running by 2050—the year when Europe is slated to make its transition.
