An unsuccessful attempt to place an unnamed satellite, Vanguard 1B, into orbit, the rocket was launched on 5 February 1958.

The skinny second stage broke in half from aerodynamic stress, causing the Vanguard to tumble end-over-end before a range safety officer sent the destruct command.

The program objectives for the satellite were to conduct micrometeorite impact and geodetic measurements from Earth orbit.

[11] The launch took place on 5 February 1958 at 07:33 GMT from the Atlantic Missile Range, from LC-18A in Cape Canaveral Air Force Station, Florida.

It contained a set of mercury-batteries, a 10 mW, 108 MHz telemetry transmitter powered by the batteries, and a 5 mW, 108.03 MHz Minitrack beacon transmitter, which was powered by six square (roughly 5 cm on a side) solar cells, manufactured by Bell Laboratories, mounted on the body of the satellite.

The transmitters were primarily for engineering and tracking data, but were also to determine the total electron content between the spacecraft and ground stations.

Vanguard also carried two thermistors which could measure the interior temperature to track the effectiveness of the thermal protection.

[11] The first stage of the three-stage Vanguard Test vehicle was powered by a General Electric GE X-405 liquid rocket engine, of 125,000 N (28,000 lbf) of thrust, propelled by 7,200 kg (15,900 lb) of kerosene (RP-1) and LOX, with helium pressurant.

[11] The second stage was a 5.8 m (19 ft) high, 0.8 m (2 ft 7 in) diameter Aerojet General AJ-10 liquid engine burning 1,520 kg (3,350 lb) Unsymmetrical Dimethylhydrazine (UDMH) and White Inhibited Fuming Nitric Acid (WIFNA) with a helium pressurant tank.