Launch Date December 15, 1960 | 09:10 UT
Launch Site Cape Canaveral, Florida, USA | Launch Complex 12 ​
Destination Earth's Moon
Type Orbiter
Status Unsuccessful
Nation United States
Alternate Names Atlas-Able VB, Pioneer-Z


Pioneer P-31, or Able VB, was another attempt to place a heavily-instrumented spacecraft into lunar orbit. The spacecraft was equipped to study radiation and magnetic fields at the Moon and measure the number of micrometeoroids.


None. The spacecraft's booster rocket exploded 68 seconds after launch, scattering debris into the Atlantic Ocean.

In Depth

The mission of Able VB, as with its two unsuccessful predecessors, was to enter lunar orbit. Scientific objectives included studying radiation near the Moon, recording the incidence of micrometeoroids, and detecting a lunar magnetic field. Planned lunar orbital parameters were about 2,700 x 1,500 miles (4,300 x 2,400) kilometers with a period of 9 to 10 hours.

The spacecraft had a slightly different scientific instrument complement from that of its predecessors. This was third and last attempt by NASA to launch a probe to orbit the Moon in the 1959-60 period.

Unfortunately, the Atlas-Able booster exploded 68 seconds after launch at an altitude of about 7.6 miles (12.2 kilometers). Later investigation indicated that the cause was premature Able stage ignition while the first stage was still firing.


Launch Vehicle: Atlas-Able (no. 3 / Atlas D no. 91)

Spacecraft Mass: 388 pounds (176 kilograms)

Spacecraft Instruments:

  1. micrometeoroid detector
  2. high-energy radiation counter
  3. ionization chamber
  4. Geiger-Mueller tube
  5. low-energy radiation counter
  6. two magnetometers
  7. Sun scanner
  8. plasma probe
  9. scintillation spectrometer
  10. solid state detector

Additional Resources

National Space Science Data Center Master Catalog: Pioneer P-31

Selected References

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

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