17 August 1958

Thor-Able 1 Pioneer launch, 17 August 1958. NASA)
Thor-Able 1 Pioneer launch, 17 August 1958. NASA)

17 August 1958: In what was the first attempt to launch a spacecraft beyond Earth orbit, Thor-Able 1 was to place a small instrumented satellite in orbit around the Moon. Called Pioneer, the satellite carried a television camera, a micrometeorite detector and a magnetometer.

The Thor-Able was launched from the Cape Canaveral Air Force Station, Florida, at 12:28:00 UTC, 4 minutes behind schedule.

73.6 seconds into the flight, at an altitude of 9.9 miles (16 kilometers), the first stage of the rocket exploded. Telemetry from the upper stages continued and that was tracked until impact in the Atlantic Ocean. An investigation found the cause to be a turbopump failure.

The Thor Able was a two-stage orbital launch vehicle which was developed from the Douglas Aircraft Company’s SM-75 Thor intermediate-range ballistic missile.

Designated Thor DM-19, the first stage was 60.43 feet (18.42 meters) long and 8 feet (2.44 meters) in diameter. Fully fueled, the first stage had a gross weight of 108,770 pounds (49,337 kilograms). It was powered by a Rocketdyne LR-79-7 engine which burned liquid oxygen and RP-1 (a highly-refined kerosene rocket fuel) and produced 170,565 pounds of thrust (758.711 kilonewtons). This stage had a burn time of 2 minutes, 45 seconds.

The second stage was an Aerojet General Corporation-built Able, a second stage for the U.S. Navy’s Vanguard rocket. It was 21 feet,6.6 inches (6.57 meters) long with a maximum diameter of 2 feet, 9 inches (0.84 meters). The second stage had a gross weight of 5,000 pounds (2,268 kilograms). It used an Aerojet AJ10-101 rocket engine which burned a hypergolic  mixture of nitric acid and UDMH. The second stage produced 7,711 pounds of thrust (34.300 kilonewtons) and burned for 1 minutes, 55 seconds.

© 2017, Bryan R. Swopes

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