Lunar dreams, powered by atom

A little over 50 years after Apollo 17 astronauts set foot on the moon, multiple countries and companies are joining an ever-intensifying race to stake claims to the lunar surface. At least three countries — the US, China, and Russia — have announced plans to put humans there by the end of this decade. India is also gearing up to launch its Chandrayaan 3 mission comprising three modules, propulsion, lander and rover, in the second week of July this year — a stepping stone in its quest of sending humans there.

There are plans to eventually establish research stations there which may serve as staging posts to future missions to Mars — all powered by nuclear energy. Why? Because, according to Thomas Zurbuchen, associate administrator for Nasa’s Science Mission Directorate, “Future nuclear power and propulsion systems will help revolutionise our understanding of the solar system and beyond and play a crucial role in enabling long-term human missions to the moon and Mars (www.nasa.gov).”

Last year, Nasa and the US Department of Energy selected three concept proposals for a fission power system design “that could be ready to launch by the end of the decade for a demonstration on the moon”. The fission surface power project focuses on a 10-kilowatt class lunar demonstration.

The US’ biggest rival in space exploration, China, too, is banking on nuclear energy to power its moon base. According to Wu Weiren, chief designer of the Chinese lunar exploration programme, the country’s research station at the south pole — expected to be up and running from 2028 — will be powered by nuclear energy. The reactor will generate 1 megawatt of electric power.

In March this year, Rolls-Royce secured £2.9 million, or $3.5 million, from the UK Space Agency to develop a nuclear reactor for a moon base. 

Rolls-Royce engineers are working on a micro modular reactor programme. If all goes as planned, by 2029, Rolls-Royce will have a reactor ready to be launched. “It is a very small reactor which we can absolutely launch into space. It’s about the size of a car,” said Abi Clayton, director, future programmes, Rolls-Royce Submarines, in a video release. “It absolutely allows people to live on the moon… you gotta be able to create oxygen, water for people to live on, heating, lighting and then you probably got things like rovers or machines that you want to use on the moon’s surface and they’ll need charging with something.”  

Nasa believes the first lunar inhabitants will need around 40 kilowatts of power. For exploration on the sunlit side of the lunar surface, we can depend on solar energy. It is noteworthy that 6 trillion kg of frozen water is estimated on the moon but most of this section lies in the darkest areas — the poles, and to study the dark side, which receives little to no sunlight, fission reactors can provide constant power. 

But how are the US, China, and Rolls-Royce planning to set up nuclear reactors? While all these programmes are in the nascent stage and specifications remain sketchy, the lab collaborating with Nasa to put a fission reactor on the moon has suggested it be uranium-powered, weighing no more than 6,000 kg. It must fit into a rocket within specified dimensions and have temperature controls to withstand over 1000C fluctuations in day and night temperatures.

The US is not new to sending nuclear batteries into the space — its crowning glory being the radioisotope thermoelectric generator (RTG) units on Voyager 1 & 2, which have reached “interstellar space”, and New Horizons, which conducted a flyby study of Pluto and its moons in 2015.

Launched in 1965, the US’ SNAP-10A was the world’s first nuclear reactor in space. It was operational for just 43 days and produced 500 watts of power. 

The same cannot be said for China. The only publicly known nuclear device it has sent into space is a small radioactive battery on Yutu 2, the rover that landed on the moon’s far side in 2019. The battery could generate only a few watts of heat.  

Keeping in mind how crucial nuclear fission power is for the future of space explorations, the U R Rao Satellite Centre (Isro’s lead centre for design, development, fabrication and testing of all Indian made satellites), two years ago, invited proposals for the three-phase development of a 100-watt RTG. 

Russia is planning a huge spacecraft powered by a megawatt-sized nuclear reactor, before 2030. This will allow the spacecraft to operate for over a decade in the Earth’s lower orbit, carrying out additional missions to the moon or beyond. The European Space Agency has launched a similar project, Democritos, with a 200-kilowatt space reactor.

It’s ironic that while nuclear power plant construction is shrinking worldwide, the power of the atom will be fuelling our dream to become an extraterrestrial species — first Lunar, then Martian, and so on.