18 September 1959: At 12:20:07 a.m., Eastern Standard Time (05:20:07 UTC), a three-stage Vanguard Satellite Launch Vehicle lifted off from Launch Complex 18A at the Cape Canaveral Air Force Station on the eastern coast of Florida. The rocket placed a 50 pound (22.7 kilogram) scientific satellite, Vanguard 3 (also known as Vanguard III) into Earth orbit. Orbital injection occurred at 05:29:49, 9 minutes, 35 seconds after launch, at 27,195 feet per second (98,239 meters per second). The orbit was inclined 33.350°. The satellite’s perigee, the closest point in its orbit to Earth, was 512.00 kilometers (318.142 statute miles), and its apogee, 3,750.00 kilometers (2,330.142 statute miles). The orbital period was 2 hours, 10 minutes, 9 seconds.

Contained inside the satellite’s 1 foot, 8.0 inch (50.8 centimeter) diameter magnesium spherical outer shell were sensors and transmitters. The satellite collected data on the Earth’s magnetic field, the Van Allen Radiation Belt, micrometeorite impacts on the satellite, and measured drag acting to slow the satellite in its orbit. The 2 foot, 2 inch (0.66 meter) cone-shaped structure at the top of the satellite contains a magnetometer.

Vanguard 3 transmitted data for 84 days before its batteries failed. It is estimated that it will remain in orbit around the Earth for 300 years.

The Vanguard Satellite Launch Vehicle was a three-stage rocket, using liquid fuel for the first and second stages, while the third stage used a solid fuel rocket motor. It was built by the Glenn L. Martin Company at Baltimore, Maryland. The rocket had a total length of 71 feet, 6.721 inches (21.8115 meters), including the payload fairing. SLV-7 (also known as TV-4BU) was an unused test article. The all-up vehicle weighed 23,143 pounds (10,497.488 kilograms) at the time of the firing signal.

The Vanguard first stage was powered by a General Electric Hermes X-405 (LR50-GE-1) engine, fueled by liquid oxygen and Shell Oil Company Jet B (a naptha-kerosene fuel used for turbojet engines in cold weather conditions). The propellant system was pressurized with helium. Hydrogen peroxide was used to drive the engine’s turbopump. The X-405 weighed 425 pounds (192.8 kilograms) and produced 27,835 pounds of thrust (123.816 kilonewtons) at Sea Level. The first stage was 39 feet, 7.243 inches (12.0712 meters) long and 3 feet, 9 inches (1,143 meters) in diameter. Its empty weight was 1,599 pounds (725.29 kilograms). The stage had a burn time of 2 minutes, 30 seconds.

The second stage was 18 feet, 7.54 inches (5.6779 meters) long and 2 feet, 8 inches (0.8128 meters) diameter, and had an empty weight 1,013 pounds (459.49 kilograms). It was powered by an Aerojet General AJ10-37 engine, fueled by a hypergolic mixture of white inhibited fuming nitric acid (WIFNA) and unsymmetrical dimethylhydrazine (UDMH). The engine weighed 386 pounds (175.09 kilograms). It produced 7,500 pounds (33.362 kilonewtons) thrust in vacuum. It had a burn time of 2 minutes.

The Vanguard SLV-7 third stage was 5 feet, 10.29 inches (1.7854 meters) long and 2 feet, 8 inches (0.8128 meters) in diameter. It weighed 50.9 pounds (23.09 kilograms) burn time 37 seconds. The engine was a solid fuel Allegany Ballistic Laboratory ¹ JATO X-248 A2, originally designed for rocket assisted takeoff for fixed wing aircraft. The engine was 4 feet, 10.2 inches (1.478 meters) long, 1 foot, 6.0 inches (0.457 meters) in diameter, and weighed 203 pounds (92.1 kilograms). It produced 3,070 pounds (13.656 kilonewtons) of thrust and had a burn time of 37 seconds.

The satellite was enclosed in a conical phenolic plastic fairing, which had a titanium tip.. The fairing was 12 feet, 6.72 inches (3.8283 meters) long. The cone angled 20° from its axis.

Third stage was left attached to the satellite. The total mass placed in orbit was 94.6 pounds (42.91 kilograms).

¹ Allegany Ballistics Laboratory was a Naval Sea Systems Command (NAVSEA) facility, operated by the Hercules Powder Company.

© 2024, Bryan R. Swopes