Editing Luna 1 (section)

==Experiment results==
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| image1 = [http://mentallandscape.com/L_Sodium2.jpg Image of sodium cloud]<ref name="o999">{{cite web | last=Mitchell | first=Don P. | title=Lunar Impact | website=Don P. Mitchell | date=1959-01-02 | url=http://mentallandscape.com/L_Luna2.htm | access-date=2024-07-17}}</ref>{{Image requested inline |date=July 2024}}
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At 00:57 GMT on 3 January 1959, at a distance of {{convert|113000|km}} from Earth,{{sfn|Siddiqi|2018|p=11}} {{convert|1|kg}} of [[sodium]] gas was released by the spacecraft, forming a cloud behind it to serve as an artificial [[comet]]. The cloud was released for two purposes: to allow visual tracking of the spacecraft's trajectory<ref>{{cite news |url=https://www.newspapers.com/clip/38763128/st_louis_postdispatch/|title=Soviet Moon Rocket Releases Sodium Cloud as 'Tail Light'|newspaper=St. Louis Post Dispatch|location=St. Louis, Missouri|date=3 January 1959|page=2|agency=Associated Press|last1=Carey|first1=Frank E.|via=Newspapers.com}}</ref> and to observe the behavior of gas in space.<ref name=nssdc/> This glowing orange trail of gas, visible over the [[Indian Ocean]] with the brightness of a sixth-magnitude star for a few minutes, was photographed by Mstislav Gnevyshev at the Mountain Station of the Main Astronomical Observatory of the [[Academy of Sciences of the USSR]] near [[Kislovodsk]].<ref name="BSE59"/>

While traveling through the outer [[Van Allen radiation belt]], the spacecraft's [[scintillator]] made observations indicating that a small number of high-energy [[Subatomic particle|particle]]s exist in the outer belt. The measurements obtained during this mission provided new data on the Earth's radiation belt and [[outer space]]. The craft was unable to detect a lunar [[magnetic field]] which placed an upper limit on its strength of 1/10,000th of Earth's.<ref name=nssdc/><ref name=Huntress235>{{cite book|last1=Huntress Jr|first1=Wesley T.|last2=Marov|first2=Mikhail Ya|date=2011|title=Soviet Robots in the Solar System Mission Technologies and Discoveries|url=https://archive.org/details/sovietrobotssola00jrwe|url-access=limited|publisher=Springer-Praxis|page=[https://archive.org/details/sovietrobotssola00jrwe/page/n255 235]|isbn=978-1-4419-7897-4}}</ref> The first-ever direct observations and measurements of [[solar wind]],{{sfn|Harvey|2007a|p=26}}<ref name=nssdc/> a strong flow of [[Plasma (physics)|ionized plasma]] emanating from the Sun and streaming through interplanetary space, were performed.<ref name=nssdc/> The ionized plasma concentration was measured to be some 700 particles per cm<sup>3</sup> at altitudes of 20,000–25,000&nbsp;km and 300 to 400 particles per cm<sup>3</sup> at altitudes of 100,000–150,000&nbsp;km.<ref name="BSE59">{{cite book |trans-title=Yearbook of the [[Great Soviet Encyclopedia]] |year=1959 |publisher=Sovetskaya Enciklopediya |location=Moscow |language=ru |issn=0523-9613 |chapter=Soviet Space Rocket |title=Ežegodnik Bolʹšoj Sovetskoj Ėnciklopedii | chapter-url=http://epizodsspace.testpilot.ru/bibl/ejeg/1959/59.html#l1|url-status=dead|archive-url=https://web.archive.org/web/20080118033153/http://epizodsspace.testpilot.ru/bibl/ejeg/1959/59.html#l1| archive-date=2008-01-18}}</ref> The spacecraft also marked the first instance of radio communication at the half-million-kilometer distance.