McAfee was a mathematician and physicist who first calculated the speed of the moon. He was part of the Project Diana team at Camp Evans, part of Fort Monmouth. Project Diana aimed to prove that a high frequency radio signal could pierce the ionosphere by bouncing a radio wave off the moon. In order to do so, the US Army needed to determine the speed of the moon. According to Dr. Henry Louis Gates, "Official news of this scientific breakthrough did not include McAfee's name, nor was there any recognition of the essential role he played. But Americans could not have walked on the moon had it not been for Walter S. McAfee and his calculations." McAfee died in 1995 in his South Belmar, New Jersey home.