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What did Voyager 2 learn about Triton’s size?
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Triton
Image of Triton, Neptune's largest satellite, captured by a camera aboard Voyager 2, 1989.
During its 1989 flyby, the Voyager 2 spacecraft provided precise measurements of Triton, revealing that the moon is approximately 2,706 km (1,681 miles) across.1
Prior to this encounter, estimates of Triton’s size were inaccurate because they relied on an erroneously high mass determination and an assumption of low surface reflectivity. Voyager 2’s observations corrected these misconceptions, establishing that Triton is nearly the diameter of Earth’s Moon and possesses a highly reflective, icy surface.12