Pioneer 2

For this third Air Force launch of a lunar orbiter, engineers introduced a number of changes to the Thor-Able launcher. Image Credit: NASA/JPL

Launch Date November 8, 1958 | 07:30 UT
Launch Site Cape Canaveral, Florida, USA | Launch Complex 17A
Destination Earth's Moon
Type Orbiter
Status Unsuccessful
Nation United States
Alternate Names Able 3

Goals

Study electromagnetic radiation in interplanetary space, photograph and orbit the Moon.

Accomplishments

A malfunction left Pioneer 2 stranded in Earth orbit. Scientists managed to gather data about energy flux and micrometeoroids before the spacecraft fell back to Earth after only 45 minutes in orbit.

In Depth

For this third Air Force launch of a lunar orbiter, engineers introduced a number of changes to the Thor-Able launcher.

The probe included a new TV scanner and a new type of battery, as well as a new cosmic-ray telescope to study the Cherenkov Effect.

Pioneer 2, like its predecessors, never reached its target. A signal from the ground shut down the Thor launch vehicles stage 2 earlier than planned. Additionally, when the X-248 third stage engine separated, it failed to fire. As a result, the probe burned up in Earth’s atmosphere only 45 minutes after launch.

During its brief mission, it reached an altitude of 1,550 kilometers and sent back data that suggested that Earth’s equatorial region had higher flux and energy levels than previously thought. The information also indicated that micrometeoroid density was higher near Earth than in space.

Investigators concluded that the third-stage engine had failed to fire because of a broken wire.

Spacecraft

Launch Vehicle: Thor-Able I (no. 2 / Thor no. 129 / DM-1812-6)

Spacecraft Mass: 87 pounds (39.6 kg)

Spacecraft Instruments:

  1. ionization chamber
  2. Magnetometer
  3. temperature sensor
  4. micrometeoroid sensor
  5. proportional counter
  6. imaging system

Additional Resources

National Space Science Data Center Master Catalog: Pioneer 2

Selected References

Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.​

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