The U.S. Navy's Naval Research Laboratory (NRL) was chosen to direct the satellite project in part due to their success with the Viking sounding rocket program.

On 6 December 1957, the first complete Vanguard rocket (TV-3), with three live stages and carrying a minimal satellite with no scientific experiments, blew up two seconds after liftoff.

Two months later, on 5 February 1958, the identically configured TV-3BU broke up when a control system malfunction, after 57 seconds of normal flight, caused the Vanguard rocket to exceed a 45° angle of attack.

[3]: 223 Vanguard TV5's satellite was a 9.75 kg (21.5 lb), 50.8 cm (20 inches) diameter sphere whose shell was composed of magnesium coated with highly polished silicon monoxide.

A 108.00 MHz transmitter at 80 milliwatts was designed to provide tracking and telemetry, transmitting and receiving using four protruding metal rod antennas.

Following this, however, two electric relays malfunctioned and failed to transmit the signal to arm the coasting flight control system, preventing the third stage from separating and firing.