Before microchips, before electronic calculation, before nanosecond data processing, the human brain deciphered the most difficult numeric equations. In NASA's early years that meant flesh-and-blood computers, mathematically gifted individuals tasked with analysis and verification of complex aerospace data. Among NASA's human computers, one of the most recognized is Katherine Johnson. In 1953 she was hired at NASA_Langley's all-Black West Area Computing Section, headed by fellow West Virginian Dorothy Vaughan. Johnson would become an integral part of the Space Task Group, a core group of researchers who made American crewed space travel a reality. She did trajectory analysis for Alan Shepard's May 1961 mission, Freedom 7, America's first human spaceflight. Johnson verified the orbital equations controlling the trajectory of the capsule in John Glenn's Friendship 7 mission, from blastoff to splashdown — calculations that would help to sync Project Apollo's Lunar Lander with the Moon-...