Why do we need space-borne nuclear power?

Solar energy has been the go-to option for most space missions, but what could be the future energy source beyond Earth?

In August, NASA's interim administrator Sean Duffy announced plans to install a nuclear reactor on the lunar surface by 2030. This move is framed as part of a new space race with China to secure resource-rich lunar regions.

Meanwhile, China launched the International Lunar Research Station (ILRS) project in 2017. This station, built through global collaboration, will include an energy source likely powered by nuclear energy.

To date, the ILRS has already attracted over 50 international institutions, including those from Africa, Asia, and Europe, reflecting its inclusive "joint construction and shared benefits" philosophy.

How feasible is it to build reactors on the moon, and what could this mean for humanity's deeper space ambitions?

Why do we need a nuclear station on the moon?

The surface area of the moon is approximately 37.9 million square kilometers, comparable to the total land surface area of Earth.

Most of the lunar bases planned to date are located near the poles of the moon, specifically in regions with near-constant sunlight for power and access to craters that contain vital water ice. The poles also offer unique advantages for maintaining stable temperatures. However, there are areas of greater scientific significance.

"From the scientific research, we need to set up base near the equator and in other low-altitude regions," said Yang Yuguang, the chair of the Space Transportation Committee of the International Astronautical Federation.

These areas usually have a high concentration of resources like helium-3 in the lunar soil for mining purposes. It will face the most dramatic shifts between intense heat during the lunar day and extreme cold during the lunar night that lasts for 14 days – solar panels are out of the option.

"But, we have another choice," Yang said, "nuclear power."

He added that it is also much more powerful than the solar panels in terms of energy transmission efficiency, with a power supply of up to a million kilowatts.

Nuclear power in space isn't a new idea. Since the 1960s, the U.S. and the Soviet Union have relied on radioisotope generators that use small amounts of radioactive elements – a type of nuclear fuel – to power satellites, Mars rovers and the Voyager probes.

The United Nations also recognizes that nuclear energy may be essential for missions where solar power is insufficient. This resolution sets guidelines for safety, transparency and international consultation.

The challenges of setting up a nuclear power plant on the moon

Establishing a nuclear power plant on the moon presents daunting safety challenges, especially during the launch, orbital transfer and landing of radioactive materials.

"Until today, no one can say that their rocket is 100 percent reliable," Yang said.

Any failure during these stages could lead to severe radioactive contamination.

History offers sobering reminders. The Soviet Union's Kosmos 367 mission in 1970, which attempted to place a nuclear-powered satellite into orbit, ended in a catastrophic launch failure that destroyed its onboard reactor. Later incidents, including Kosmos 954's uncontrolled reentry over Canada in 1978 and Kosmos 1402's crash in 1983, highlighted the persistent risks of handling nuclear reactors in space.

Nuclear power for future space ambitions

"Space-borne nuclear power is extremely important for our future space ambitions," Yang said.

Apart from the lunar bases, Yang believes we will "sooner or later ... set up permanent base on the Martian surface."

For a long-term stay and scientific exploration on Mars, nuclear power is more ideal, given the weeks-long, planet-wide dust storms that often shroud the gigantic Red Planet.

Other celestial bodies in the outer solar system are worth exploring through orbital missions and landings.

"One important task for our scientists is to find the traces or the evidence of life forms in other celestial bodies in the solar system," Yang said.

Yang notes that the possibility exists on Mars, as well as on Saturn's moon Titan and the moons of Jupiter, which are believed to harbor vast oceans beneath their icy surfaces.

"If we want to explore these celestial bodies, we do need nuclear power," he said.

Yang is also hoping to explore Uranus and Neptune with missions possible within this century.