Actually I'm off by a couple of days, I'm referring to Dec. 6, 1958. Oh well.
Pioneer 3 was a plucky step forward for the USA. It was originally meant to be a lunar probe. Its job was to fly close enough to the moon to have the lunar light activate a photosensor which would trigger a camera. This probe did not include the camera, but was meant to test the trigger device. In the actual event, the satellite did not reach escape velocity and did not go into a solar orbit.
After reaching almost 110,000 kilometers from the Earth, the little probe began to fall back in Earth's gravity. Revised objectives allowed scientists to use the probe to investigate the Van Allen radiation belt which had been discovered by our first satellite to orbit, Explorer 1. The data from Pioneer 3 helped Dr. Van Allen to eventually discover a second belt of radiation around the planet.
The photo shows scientists assembling the probe. The launch was conducted by both NASA and the US Army Ballistic Agency (where good old Dr. Von Braun was working).
