Editing Solar sail (section)

==History of concept==
[[Johannes Kepler]] observed that [[comet]] tails point away from the [[Sun]] and suggested that the Sun caused the effect. In a letter to Galileo in 1610, he wrote, "Provide ships or sails adapted to the heavenly breezes, and there will be some who will brave even that void."<ref>"Da naves aut vela coelesti aurae accommoda, eruntqui ne ab illa quidem vastitate sibi metuant." - ''Dissertatio cum Nuncio Sidereo''</ref> He might have had the comet tail phenomenon in mind when he wrote those words, although his publications on comet tails came several years later.<ref>Johannes Kepler (1604) ''Ad vitellionem parali pomena'', Frankfort; (1619) ''De cometis liballi tres '', Augsburg</ref>

The theory of [[electromagnetic field]]s and radiation, first published by [[James Clerk Maxwell]] in 1861–1864, shows that light has [[momentum]] and thus can exert pressure on objects. [[Maxwell's equations]] provide the theoretical foundation for sailing with light pressure. So by 1864, the physics community and beyond knew [[sunlight]] carried momentum that would exert a pressure on objects.

[[Jules Verne]], in ''From the Earth to the Moon'',<ref name="Verne1865">Jules Verne (1865) ''De la Terre à la Lune'' (''From the Earth to the Moon'')</ref> published in 1865, wrote "there will some day appear velocities far greater than these [of the planets and the projectile], of which light or electricity will probably be the mechanical agent ... we shall one day travel to the moon, the planets, and the stars."<ref name="Impey">Chris Impey, ''Beyond: Our Future in Space,'' W. W. Norton & Company (2015)</ref> This is possibly the first published recognition that light could move ships through space.

[[Pyotr Lebedev]] was first to successfully demonstrate light pressure, which he did in 1899 with a torsional balance;<ref>P. Lebedev, 1901, "Untersuchungen über die Druckkräfte des Lichtes", ''Annalen der Physik'', 1901</ref> Ernest Nichols and Gordon Hull conducted a similar independent experiment in 1901 using a [[Nichols radiometer]].<ref>{{cite web|url=http://dujs.dartmouth.edu/spring-2008-10th-anniversary-edition/what-else-has-happened-a-celebration-of-the-legacy-of-physics-at-dartmouth|title=A Celebration of the Legacy of Physics at Dartmouth |last=Lee|first=Dillon |year=2008|work=Dartmouth Undergraduate Journal of Science|publisher=Dartmouth College|access-date=2009-06-11}}</ref>

[[Svante Arrhenius]] predicted in 1908 the possibility of solar radiation pressure distributing life spores across interstellar distances, providing one means to explain the concept of [[panspermia]]. He was apparently the first scientist to state that light could move objects between stars.<ref>Svante Arrhenius (1908) ''Worlds in the Making''</ref>

[[Konstantin Tsiolkovsky]] first proposed using the pressure of sunlight to propel spacecraft through space in 1921<ref>{{Cite web |last=Hollerman |first=William Andrew |orig-date=April 1, 2003 |title=The Physics of Solar Sails |url=https://ntrs.nasa.gov/api/citations/20030093608/downloads/20030093608.pdf |url-status=bot: unknown |archive-url=https://web.archive.org/web/20241112105705/https://ntrs.nasa.gov/api/citations/20030093608/downloads/20030093608.pdf |archive-date=November 12, 2024 |access-date=May 16, 2025 |website=[[NASA_STI_Program|NASA  Scientific and Technical Information Repository]] }}</ref> and suggested "using tremendous mirrors of very thin sheets to utilize the pressure of sunlight to attain cosmic velocities".<ref>Urbanczyk, Mgr., "Solar Sails-A Realistic Propulsion for Space Craft", Translation Branch Redstone Scientific Information Center Research and Development Directorate U.S. Army Missile Command Redstone Arsenal, Alabama, 1965.</ref>

[[Friedrich Zander]] (Tsander) published a technical paper in 1925 that included technical analysis of solar sailing. Zander wrote of "applying small forces" using "light pressure or transmission of light energy to distances by means of very thin mirrors".<ref>Friedrich Zander's 1925 paper, "Problems of flight by jet propulsion: interplanetary flights", was translated by NASA. See NASA Technical Translation F-147 (1964), p. 230.</ref>

[[JBS Haldane]] speculated in 1927 about the invention of tubular spaceships that would take humanity to space and how "wings of metallic foil of a square kilometre or more in area are spread out to catch the Sun's radiation pressure".<ref>JBS Haldane, ''The Last Judgement'', New York and London, Harper & Brothers, 1927.</ref>

[[J. D. Bernal]] wrote in 1929, "A form of space sailing might be developed which used the repulsive effect of the Sun's rays instead of wind. A space vessel spreading its large, metallic wings, acres in extent, to the full, might be blown to the limit of Neptune's orbit. Then, [[Gravity assist|to increase its speed]], it would tack, close-hauled, down the gravitational field, spreading full sail again as it rushed past the Sun."<ref>J. D. Bernal (1929) ''The World, the Flesh & the Devil: An Enquiry into the Future of the Three Enemies of the Rational Soul''</ref>

[[Arthur C. Clarke]] wrote ''[[Sunjammer]]'', a [[science fiction]] [[short story]] originally published in the March 1964 issue of ''[[Boys' Life]]'' <ref name=Arthurcclarke>[http://www.arthurcclarke.net/?scifi=1&type=4 Short Stories] {{Webarchive|url=https://web.archive.org/web/20111002023436/http://www.arthurcclarke.net/?scifi=1&type=4 |date=2011-10-02 }}. ''Arthurcclarke.net'', 2007-2011, retrieved June 22, 2011</ref> depicting a yacht race between solar sail spacecraft. 

[[Carl Sagan]], in the 1970s, popularized the idea of sailing on light using a giant structure which would reflect [[photons]] in one direction, creating momentum. He brought up his ideas in college lectures, books, and television shows. He was fixated on quickly launching this spacecraft in time to perform a rendezvous with [[Halley's Comet]]. Unfortunately, the mission didn't take place in time and he would never live to finally see it through.<ref>{{cite web | url=https://www.centauri-dreams.org/2017/05/05/remembering-the-sail-mission-to-halleys-comet/ | title=Remembering the Sail Mission to Halley's Comet | author=Paul Gilster |date=May 5, 2017}}</ref>

The first formal technology and design effort for a solar sail began in 1976 at [[Jet Propulsion Laboratory]] for a proposed mission to rendezvous with [[Halley's Comet]].<ref name="Wright " />