We often take electricity for granted on Earth. But in space or on the Moon, there are no power lines, no sunlight at night and no backup grid. Every system — from life support and communication to heat, lights and research tools — runs on power. For astronauts, power keeps them alive by running machines that provide air to breathe, water to drink and a safe temperature to live in. For robots and landers, power is what allows them to move, think (process data) and send information back to Earth.
And as we start planning long-term stays on the Moon, power becomes even more important. It’ll be needed to build habitats, run labs, grow food, mine local resources and stay in touch with Earth — especially during the long, cold two-week lunar nights when the Sun doesn’t shine. This article will discuss the different ways power can be generated in space and on the Moon.
Solar power in space and on the Moon
Spacecraft: Solar panels are the predominant power source for spacecraft operating within the inner solar system. They convert sunlight into electricity, powering onboard systems and instruments. Solar panels in geostationary orbits can receive sunlight 24/7, unlike on Earth or the Moon. For instance, NASA's Juno spacecraft, despite being at Jupiter's distance where sunlight is only about 4% as intense as at Earth, utilizes large solar panels to meet its energy needs.
Lunar surface: On the Moon, solar panels are effective during the lunar day, which lasts approximately 14 Earth days. However, the subsequent 14-day lunar night poses challenges for solar energy use. To mitigate this, solar arrays are often combined with energy storage systems, such as batteries, to provide power during periods without sunlight.
Nuclear power in space and on the Moon
Spacecraft: For missions venturing beyond the inner solar system, where sunlight is insufficient, nuclear power becomes essential. Radioisotope thermoelectric generators (RTGs) have been employed to provide reliable, long-duration power for spacecraft like Voyager and New Horizons. An RTG is a nuclear battery that converts heat released from the natural radioactive decay of certain isotopes — typically plutonium-238 — into electricity using thermoelectric materials. It has no moving parts, which makes it extremely reliable for long-duration missions. The heat flows through thermoelectric materials, which convert heat directly into electricity using the Seebeck effect (a temperature difference between two materials creates an electric voltage).
[See also: Harnessing nuclear heat to warm lunar missions]
Lunar surface: To ensure continuous power supply, especially during the prolonged lunar night or in permanently shadowed regions, nuclear fission reactors are being developed. NASA's Fission Surface Power project aims to deploy a 40-kilowatt-class fission power system on the Moon by the early 2030s, providing a consistent energy source for lunar habitats. Similarly, China and Russia have announced plans to construct a nuclear power plant on the Moon's surface to support their International Lunar Research Station, targeting completion between 2033 and 2035.
In-situ solar cell production from lunar regolith
Researchers have successfully created solar cells using simulated Moon dust (regolith). These cells are efficient in converting sunlight into energy, resistant to radiation damage, and reduce the need to transport heavy materials from Earth, offering a sustainable solution for lunar energy needs.
Optical power beaming (OPB)
Studies are exploring optical power beaming as a method to transmit energy via lasers to lunar bases. This approach could provide power during lunar nights or in permanently shadowed regions. Unlike Earth, where the atmosphere can scatter and absorb light, space and the Moon have little to no atmosphere. This means the laser beam can travel with very low loss or distortion, improving efficiency and range. However, challenges such as attenuation due to lunar dust are being investigated to optimize system design.
Space-based solar power stations
The British company Space Solar is advancing the concept of space-based solar power by developing technology to construct large-scale solar power stations in Earth's orbit. These stations would collect solar energy and transmit it to Earth via radio waves. A prototype is expected to launch within four years, utilizing autonomous robots for assembly.
Honda's regenerative fuel cell system
Honda is developing a regenerative fuel cell system designed to produce electricity, oxygen and hydrogen on the Moon. Powered by solar energy, this system aims to support future lunar settlements by creating a closed-loop energy cycle, with water as the only byproduct. Components are being tested aboard the International Space Station. When the Moon will not be getting enough sunlight, a portion of the oxygen will be needed for astronaut’s breathing during lunar night. To power its fuel cell technology, Honda will utilize remaining oxygen and hydrogen created on lunar day. In a closed-loop energy cycle, the sole byproduct of the fuel cells after generating electricity is water, which is then recycled into the water electrolysis system.
Conclusion
All these innovations represent significant strides toward establishing sustainable and continuous power sources for space missions and lunar habitation. Energy supply in extraterrestrial habitats is a key challenge that space organizations and commercial enterprises are working to address this using nuclear technology, in-situ resource exploitation and enhanced energy transmission systems.
