The least successful lunar spacecraft; none even achieved orbit in four attempts.

Mass: 172 kg (379 lb).

• 1959 November 26 - Pioneer (P 3) - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC14. Launch Vehicle: Atlas. FAILURE: Payload shroud failed after 45 sec, broke away prematurely. Mass: 168 kg (370 lb). Apogee: 1,000 km (600 mi).
  An intended lunar probe launched from the Atlantic Missile Range by an Atlas-Able booster disintegrated about 45 seconds later when the protective sheath covering the payload detached prematurely. The probe was sponsored by NASA, developed by the Jet Propulsion Laboratory, and launched by the Air Force Ballistic Missile Division.

• 1960 February 15 - Pioneer (P 31) - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC13. Launch Vehicle: Atlas. FAILURE: Vehicle exploded in static firing.
  

• 1960 September 25 - Pioneer (P 30) - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC12. Launch Vehicle: Atlas. FAILURE: Second stage exploded. Mass: 175 kg (385 lb). Apogee: 1,290 km (800 mi).
  An attempt to launch a Pioneer satellite into lunar orbit failed when one of the upper stages of the Atlas- Able rocket malfunctioned.

• 1960 December 15 - Pioneer (P 31) - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC12. Launch Vehicle: Atlas. FAILURE: Atlas exploded 70 seconds after liftoff. Mass: 175 kg (385 lb). Apogee: 13 km (8 mi).
  The final launch in the Pioneer lunar probe program was unsuccessful; the Atlas-Able booster rocket went out of control and exploded at an altitude of 12,200 m off Cape Canaveral.