Editing Mariner 10 (section)

== Discoveries ==
During its flyby of Venus, ''Mariner 10'' discovered evidence of rotating clouds and a very weak magnetic field. Using a near-[[ultraviolet]] filter, it photographed Venus's [[Cirrus uncinus cloud|chevron clouds]] and performed other [[celestial body's atmosphere|atmospheric]] studies.

The spacecraft flew past Mercury three times. Owing to the geometry of its orbit – its orbital period was almost exactly twice that of Mercury's – the same side of Mercury was sunlit each time, so it was only able to [[map]] 40–45% of Mercury's surface, taking over 2,800 photos. It revealed a more or less Moon-like surface. It contributed enormously to the understanding of Mercury, whose surface had not been successfully resolved through telescopic observation. The regions mapped included most or all of the Shakespeare, Beethoven, Kuiper, Michelangelo, Tolstoj, and Discovery [[list of quadrangles on Mercury |quadrangle]]s, half of Bach and Victoria quadrangles, and small portions of Solitudo Persephones (later Neruda), Liguria (later Raditladi), and Borealis quadrangles.<ref name=h8.pdf/>

''Mariner 10'' also discovered that Mercury has a tenuous [[Atmosphere of Mercury|atmosphere]] consisting primarily of [[helium]], as well as a [[magnetic field]] and a large iron-rich [[planetary core|core]]. Its radiometer readings suggested that Mercury has a nighttime temperature of {{cvt|-183|°C|°F}} and maximum daytime temperatures of {{cvt|187|°C|°F}}.

Planning for ''[[MESSENGER]]'', a spacecraft that surveyed Mercury until 2015, relied extensively on data and information collected by ''Mariner 10''.