Mission controllers destroyed this spacecraft after a rocket booster malfunction prevented it from reaching orbit. It was the last in a series of spacecraft designed to explore interplanetary space from a wide orbit around the Sun.


During launch of this Pioneer probe, at T+31 seconds, the hydraulics system of the first stage of the booster malfunctioned, eventually causing complete loss of pressure at T+213 seconds, only 4 seconds prior to main engine cutoff of the first stage. Although second stage performance was nominal, there was no way to compensate for the large pointing error introduced by the malfunctions in the first stage.

With the booster veering off course, ground control sent a command to destroy the vehicle at T+484 seconds.

Pioneer-E was the last in a series of probes intended for studying interplanetary space from heliocentric orbit. An additional payload on the Thor Delta L was a Test and Training Satellite (TETR C) to test the Apollo ground tracking network.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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