Vanguard TV3 was the first attempt of the United States to launch a satellite into orbit around the Earth. It was a small satellite designed to test the launch capabilities of the three-stage Vanguard rocket and study the effects of the environment on a satellite and its systems in Earth orbit. It was also to be used to obtain geodetic measurements through orbit analysis.
At its launch attempt on December 6, 1957 at Cape Canaveral, the booster ignited and began to rise but about 2 seconds after liftoff, after rising about four feet (1.2 m), the rocket lost thrust and began to settle back down to the launch pad. As it settled against the launch pad the fuel tanks ruptured and exploded, destroying the rocket and severely damaging the launch pad. The Vanguard satellite was thrown clear and landed on the ground a short distance away with its transmitters still sending out a beacon signal. The satellite was damaged, however, and could not be reused. It is now on display at the National Air and Space Museum of the Smithsonian Institution.
The exact cause of the accident was never determined with certainty, but the commonly accepted explanation is that low fuel tank pressure during the start procedure allowed some of the burning fuel in the combustion chamber to leak into the fuel system through the injector head before full propellant pressure was obtained from the turbopump.
The payload was a 1.36 kg aluminum sphere 152 mm in diameter, nearly identical to the later Vanguard 1. It contained a mercury battery powered, 10 mW, 108 MHz transmitter and a 5 mW, 108.03 MHz transmitter powered by six solar cells mounted on the body of the satellite. Six short aerials protruded from the sphere. The transmitters were used primarily for engineering and tracking data, but were also used to determine the total electron content between the satellite and ground stations. Vanguard also carried two thermistors to measure the interior temperatures in order to track the effectiveness of the thermal protection.
Engineers recovered the payload from the launch area, still functioning. It was restored and put on display at the entrance to the Apollo gallery when the National Air and Space Museum opened in 1976. Since then the display has been modified to show TV3 in a condition closer to what it was found in.
Full article ▸