Ralph Belknap Baldwin (June 6, 1912 – October 23, 2010)[1] was an American planetary scientist known for his work on lunar craters, beginning in the late 1940s.

[2] His book, The Face of the Moon[3] made the case for the impact nature of lunar craters.

[6] The photographs at the Adler Planetarium, where he lectured to earn extra money, sparked his interest in lunar craters.

[8] During World War II Baldwin helped to develop the radar proximity fuze.

[1][2] The Ralph B. Baldwin Award by the Wood Machinery Manufacturers of America was established in his honor.