Launch Failure
Liftoff Time (GMT)
02:49:00
Tuesday April 14, 1959
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A momentary delay in first stage separation caused the second stage engine to ignite while still attached to the first stage. Pressure from the engine exhaust pushed the thrust chamber to the limit of the gimbal stops, breaking them and causing loss of attitude control in flight. The second stage tumbled and the resultant forces caused a premature separation of the third stage and payload. Data was received from them until impact in the Atlantic Ocean eight minutes after liftoff.
The Vanguard SLV5 satellite consisted of a 13in spherical satellite, which contained a precise magnetometer to map the Earth's magnetic field. The satellite was lost together with the Vanguard Balloon, when the Vanguard launch vehicle second stage was damaged during staging. The magnetometer was reflown on the Vanguard 3 satellite.
Medium Earth Orbit
1 Payload
10 kilograms
The Vanguard Balloon Subsatellite was a small balloon satellite to measure air-density. It was launched piggy back with the Vanguard 13in Magnetometer satellite.
Medium Earth Orbit
1 Payload
9th
Mission
2nd
Mission of 1959
6th
Orbital launch attempt