Sun gun#History
{{short description |Theoretical orbital weapon}}
{{Distinguish |Stun gun (disambiguation){{!}}Stun gun}}
The sun gun or heliobeam (German: Sonnengewehr) is a theoretical orbital weapon, which makes use of a concave mirror mounted on a satellite, to concentrate sunlight onto a small area at the Earth's surface, destroying targets or killing through heat.
History
In 1929, the German physicist Hermann Oberth developed plans for a space station from which a 100-metre-wide concave mirror could be used to reflect sunlight onto a concentrated point on the earth.{{cite journal |title=Science: Sun Gun |date=July 9, 1945 |journal=Time Magazine |url=https://content.time.com/time/subscriber/article/0,33009,852344-1,00.html}}
Later, during World War II, a group of German scientists at the German Army Artillery proving grounds at Hillersleben began to expand on Oberth's idea of creating a superweapon that could utilize the sun's energy.{{Cite web |last=Burke |first=Myles |date=February 3, 2025 |title='It could illuminate an area the size of a football stadium': How Russia launched a giant space mirror in 1993 |url=https://www.bbc.com/culture/article/20250130-how-russia-launched-a-giant-space-mirror-in-1993 |website=www.bbc.com}} This so-called "sun gun" (Sonnengewehr) would be part of a space station {{convert |8200 |km}} above Earth. The scientists calculated that a huge reflector, made of metallic sodium and with an area of {{convert |9 |sqkm |ha mi2}}, could produce enough focused heat to make an ocean boil or burn a city. After being questioned by American officers, the Germans claimed that the sun gun could be completed within 50 or 100 years.{{cite journal |title=The German Space Mirror |date=July 23, 1945 |journal=Life Magazine |page=78 |url=https://books.google.com/books?id=30kEAAAAMBAJ&pg=PA78}} Evidence that Japan was also attempting to develop a death ray was uncovered by American forces.{{Cite news |date=1945-10-07 |title=Japanese Had 'Death Ray' In Stage of Development |url=https://www.nytimes.com/1945/10/07/archives/japanese-had-death-ray-in-stage-of-development.html |access-date=2025-02-05 |work=The New York Times |language=en-US |issn=0362-4331}}{{Cite journal |last=Fanning |first=William J. |date=2010 |title=The Historical Death Ray and Science Fiction in the 1920s and 1930s |url=https://www.jstor.org/stable/25746409 |journal=Science Fiction Studies |volume=37 |issue=2 |pages=253–274 |issn=0091-7729}}{{Cite book |last=Grunden |first=Walter E. |title=Secret weapons and World War II: Japan in the shadow of big science |date=2005 |publisher=University Press of Kansas |isbn=978-0-7006-1383-0 |series=Modern war studies |location=Lawrence, Kan |pages=110-116}}
With the deployment and validation of satellite mega-constellations, their use as a sun gun has also been proposed. Instead of a vast individual mirror, hundreds of low cost reflectors could in theory be synchronized to concentrate solar irradiance and aim it at a target.{{cite web |last=Shiga |first=David |title=Space mirrors could create Earth-like haven on Mars |website=New Scientist |language=en-US |url=https://www.newscientist.com/article/dn10573-space-mirrors-could-create-earth-like-haven-on-mars/ |access-date=April 23, 2023 |url-status=live |archive-url=https://web.archive.org/web/20230423052858/https://www.newscientist.com/article/dn10573-space-mirrors-could-create-earth-like-haven-on-mars/ |archive-date=April 23, 2023}}
See also
- Archimedes' heat ray, a purported device from antiquity which weaponized the sun's rays
- 20 Fenchurch Street, a skyscraper in London whose concave reflecting face generated extremely high temperatures - hot enough to melt plastic - by reflecting the sun's rays
- Concentrated solar power
- Solar furnace
- Space-based solar power
- Space mirror (climate engineering)
- Znamya (satellite) (Not intended for use as a weapon, but similar concept of "mirrors in space" )