At the beginning of the Fifties a "lunar mission" was studied by a then obscure laboratory that was to built Explorer-1 and most of the American lunar and planetary spacecraft: JPL (Jet Propulsion Laboratory). The laboratory was created at the end of the Thirties by a group of doctoral students of professor Theodore Von Karman of Caltech, led by the first laboratory director Frank J. Malina and by the Chinese born Tsien Hsue-shen (or, according to a more recent transliteration, Qian Xuesen). 

During the Second World War Malina perfected the first modern solid fueled rocket, used on heavy bombers for rocket assisted take-off and after the war the laboratory continued to work for the Army, designing and building a series of liquid fueled missiles that were designated with the military degrees: the first engine was called Private, the next Corporal and the last Sergeant. The most famous JPL product of that time was a small scale prototype of Corporal called WAC Corporal (Without Attitude Control), some of which were used as a second stage of V-2, reaching altitudes of more than 400 km and inaugurating, on 1950, the atlantic coast missile range which becamethe Cape Canaveral "spaceport". While working on this historic project, some laboratory engineers calculated, as a joke, that by using the full scale Corporal missile and a cluster of anti aircraft Loki solid fueled rockets, it was possible to hurl to the Moon... an empty beer can!

At the end of October 1957, JPL proposed the first serious US project of lunar exploration, called "project Red Socks". The project, born in response of Sputnik had three main objectives: to take pictures of the lunar hidden hemisphere, to improve satellite guiding techniques and... to impress the world (sic!).

It was proposed to launch no less than nine different probes: the first would have used a very similar technology to Explorer (built by JPL itself), would have weighted 6.75 kg on Earth and would have orbited the Moon as early as June 1958. The second was to have taken pictures of the hidden side of the Moon and would have returned them to Earth using a re-entry body similar to the one developed for the Jupiter missile. Seven other missions would have put 54 kg mass satellites in orbit around the Moon between January 1959 and the end of 1960.

The objectives of these following missions were still quite unclear, so much so that the laboratory's director, Pickering, proposed to explode a nuclear weapon on the surface of our natural satellite, so as to acquire with a very small effort any lunar rock that would have been hurled to our planet by the explosion and to produce "beneficial psychological results".

Not bad, for a nation that still had to launch an artificial satellite of its own! In the end, while Red Socks cleared the way for Project Able, which produced the first unsuccessful US lunar probes, all of the stunts projected for Red Socks (except for the nuclear bomb, of course!) were accomplished by the Soviets:
1) First picture of the Lunar farside: Luna-3, 1959
2) First Lunar orbiter: Luna-10 1966
3) First Circumlunar mission with Earth re-entry: Zond-5 1968

Bibliography

• Koppes, C: JPL and the American Space Program, Yale University Press, p. 78-85
• Red Socks page at JPL
• Wilson, A.: The Eagle has Wings; London, British Interplanetary Society, p. 18