The Cow Jumped Over the Moon (1957)
In June 1957, launch of the civilian U.S. Vanguard scientific satellite (image at top of post) was thought imminent. That month, Krafft Ehricke and George Gamow wrote in Scientific American magazine that, after Vanguard reached low-Earth orbit, the moon, 238,000 miles away, would be “the next interesting target in space.” They estimated that, with “luck and sufficient effort,” a U.S. automated probe could reach the moon by 1963.
Ehricke and Gamow proposed a design for such a probe, which they inelegantly dubbed “Cow” in tribute to the moon-jumping nursery rhyme character. Cow would have a mass of between 400 and 800 pounds. A 100-foot-tall, 120-ton rocket would boost it to a speed of 23,827 miles per hour on a path toward the moon. If the Earth existed in isolation, Cow would then enter an elliptical orbit around the Earth taking it 280,000 miles out into space – that is, about 45,000 miles beyond the moon. The gravitational attraction of the moon and Sun meant, however, that Cow would follow a “distorted” path to a point 1281 miles from the moon 75.6 hours after launch. The probe would then swing around the moon, collecting data all the while, and fall back to Earth.
Cow would strike Earth’s atmosphere moving at 25,000 miles per hour 157 hours after launch. Though high-speed reentry would drive Cow’s skin temperature to 5000° C, Ehricke and Gamow maintained that “preventing the capsule from burning up by means of insulation and a cooling system” would not be “technically prohibitive.” This would enable recovery of high-quality photographic film images and other recorded data.
Ehricke and Gamow then proposed an explosive follow-on mission that would employ two probes launched on a “Cow-type” trajectory. The lead probe would drop an atomic bomb on the moon, blasting a debris cloud far into space; then, through “a miracle of electronic guidance,” the trailing probe would “dive into the cloud, collect some of the spray and emerge from its dive by means of an auxiliary jet.” It would then fall to Earth bearing its precious cargo of lunar material. This was one of a host of U.S. and Soviet proposals to explode nuclear weapons on the lunar surface put forward in the late 1950s/early 1960s, none of which reached fruition.
On 4 October 1957, the Soviet Union launched the first Earth satellite. Though the Soviets had announced two years previously that they aimed to launch a satellite, few in the West had taken them seriously. A second satellite, Sputnik 2, reached orbit with the dog Laika on board on 3 November 1957.
The first Vanguard launch attempt, designated TV3, ended in a nationally televised launch pad explosion on 6 December 1957, heaping humiliation upon humiliation. President Dwight Eisenhower, eager to calm American anxiety about Soviet technological prowess, decided not to rely solely on Vanguard. He authorized the U.S. Army rocket team under Wernher von Braun to prepare to launch a satellite as work toward the next Vanguard launch attempt proceeded. Citing technical difficulties (a fault in the Vanguard rocket’s second-stage engine), the Vanguard TV-3BU mission stood down on 26 January 1958, clearing the way for an Army Juno I rocket to launch Explorer 1, the first U.S. Earth satellite, on 31 January 1958.
The first Vanguard satellite to reach orbit left Earth on 17 March 1958. The 3.2-pound satellite, which ceased operating in 1964, remains in Earth orbit. Sputnik 1, Sputnik 2, and Explorer 1 have long since reentered the atmosphere and been destroyed, making Vanguard 1 the oldest artificial object orbiting Earth.
In August 1958, the U.S. and U.S.S.R. began to launch probes toward the moon. The Soviet Luna 2 probe became the first human-made object to strike the moon (13 September 1959) and Luna 3 imaged the moon’s hidden Farside (6 October 1959). No spacecraft would follow Ehricke and Gamow’s Cow-type trajectory until the Soviet Zond 5 (an unmanned test of a manned circumlunar spacecraft) in September 1967, and none would return samples of lunar surface material until the first manned moon landing (Apollo 11, 16-24 July 1969).
A Rocket Around the Moon, K. Ehricke and G. Gamow, Scientific American, Volume 196, Number 6, June 1957, pp. 47-53.