An artist's rendering of NASA's Pioneer spacecraft. Credit: NASA

What was Pioneer-E?

NASA's Pioneer-E was the last in a series of probes designed to study interplanetary space from heliocentric orbit. Mission controllers had to destroy the spacecraft after a rocket booster malfunction prevented it from reaching orbit.

Nation United States of America (USA)
Objective(s) Solar Orbit
Spacecraft Pioneer-E
Spacecraft Mass 144 pounds (65.4 kilograms)
Mission Design and Management NASA / ARC
Launch Vehicle Thrust-Augmented Improved Thor-Delta (Thor Delta L no. D73 / Thor no. 540)
Launch Date and Tim Aug. 27, 1969 / 21:59:00 UT
Launch Site Cape Canaveral, Fla. / Launch Complex 17A
Scientific Instruments 1. Three-Axis Magnetometer
2. Cosmic Ray Telescope
3. Radio Propagation Detector
4. Electric Field Detector
5. Quadrispherical Plasma Analyzer
6. Cosmic Ray Anisotropy Detector
7. Cosmic Dust Detector
8. Celestial Mechanics Experiment

Key Dates

Aug. 27, 1969: Launch

Aug. 27, 1969: Spacecraft destroyed

In Depth: Pioneer-E

During the 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.

Key Source

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

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