I heard that on the moon there is a substance such as helium-3. They say that it will have a lot of cheap energy. Maybe it's true?
It's false. Science fiction is not real life. Helium-3 does not exist in commercially useful quantities on the Moon, nor is it a source of energy (cheap or otherwise) without a fusion power plant.
Materials on the Moon's surface contain helium-3 at concentrations on the order of between 1.4 and 15 ppb in sunlit areas,[49][50] and may contain concentrations as much as 50 ppb in permanently shadowed regions.[5] A number of people, starting with Gerald Kulcinski in 1986,[51] have proposed to explore the moon, mine lunar regolith and use the helium-3 for fusion. Because of the low concentrations of helium-3, any mining equipment would need to process extremely large amounts of regolith (over 150 million tonnes of regolith to obtain one ton of helium 3),[52] and some proposals have suggested that helium-3 extraction be piggybacked onto a larger mining and development operation.[citation needed]
The primary objective of Indian Space Research Organisation's first lunar probe called Chandrayaan-I, launched on October 22, 2008, was reported in some sources to be mapping the Moon's surface for helium-3-containing minerals.[53] However, this is debatable; no such objective is mentioned in the project's official list of goals, while at the same time, many of its scientific payloads have noted helium-3-related applications.[54][55]
Cosmochemist and geochemist Ouyang Ziyuan from the Chinese Academy of Sciences who is now in charge of the Chinese Lunar Exploration Program has already stated on many occasions that one of the main goals of the program would be the mining of helium-3, from which operation "each year three space shuttle missions could bring enough fuel for all human beings across the world."[56] To "bring enough fuel for all human beings across the world",[57] more than one Space Shuttle load (and the processing of 4 million tonnes of regolith) per week, at least 52 per year, would be necessary.[citation needed][dubious – discuss]
In January 2006, the Russian space company RKK Energiya announced that it considers lunar helium-3 a potential economic resource to be mined by 2020,[58] if funding can be found.[59][60]
Mining gas giants for helium-3 has also been proposed.[61] The British Interplanetary Society's hypothetical Project Daedalus interstellar probe design was fueled by helium-3 mines in the atmosphere of Jupiter, for example. Jupiter's high gravity makes this a less energetically favorable operation than extracting helium-3 from the other gas giants of the solar system, however.
Not all authors feel the extraterrestrial extraction of helium-3 is feasible. Dwayne Day, writing in The Space Review, identifies some major obstacles to helium-3 extraction from extraterrestrial sources for use in fusion, and questions the feasibility of extraterrestrial extraction when compared to production on Earth.[62]
Several science fiction works have featured helium-3 extraction on the moon, including the films Moon (2009) and Iron Sky (2012), the video game Anno 2205 (2015) and the novel Luna: New Moon (2015). The novel Morning Star (Pierce Brown, 2016) features helium-3 mining on Phobos (a moon of Mars), while his novel Red Rising (2014) features helium-3 extraction from Mars itself.
https://en.wikipedia.org/wiki/Helium-3