A retired naval mathematician, West spearheaded a mathematical model of the Earth’s size and shape (a.k.a., a geoid), which is an essential layer underpinning today’s GPS networks. Since their launch in 1978, satellite navigation systems have touched nearly every aspect of both private and public life on Earth—from emergency response and power grid systems to turn-by-turn navigation and stock exchange timing. West’s contributions, however, were unknown to the public for nearly 40 years