The Pioneer series of spacecraft performed the first US exploration of the solar system. While the craft and their missions had few similarities, they all paved the way for future exploration. The program spanned 20 years and included the stunning successes of Pioneer 10 and 11.

Pioneer 0
Vehicle: Thor Able
Launch Date: 8/17/58 (by USAF, all others launched by NASA)
Mission: radiation survey of earth-moon space
Outcome: Destroyed 77 seconds after launch when first stage exploded.

Pioneer 1
Vehicle: Thor Able
Launch Date: 10/11/58
Mission: radiation survey of earth-moon space
Outcome: A programming error in its upper stage caused it to fall short of its goal. It reached an altitude of 113854 km above the Earth's surface, but fell back into the Pacific ocean two days later. It did map the extent of some of the Earth's radiation belts.

Pioneer 2
Vehicle: Thor Able
Launch Date: 11/8/58
Mission: radiation survey of earth-moon space
Outcome: The upper stage failed to ignite, causing it to reenter the atmosphere about six hours after launch.

Pioneer 3
Vehicle: Juno 2
Launch Date: 12/6/58
Mission: radiation survey of earth-moon space
Outcome: The first stage boosters cut out prematurely, but it did reach an altitude of 102,332 km and was able to return significant scientific data.

Pioneer 4
Vehicle: Juno 2
Launch Date: 3/3/59
Mission: radiation survey of earth-moon space
Outcome: Successful flyby of the Moon at a distance of 58,983 km (twice the planned altitude).

Pioneer 5
Vehicle: Thor Able
Launch Date: 3/11/60
Mission: map interplanetary magnetic fields
Outcome: Returned good data for 106 days (design life was one month), communicating from as far away as 36.2 million km. Still in solar orbit, but no longer communicating.

Pioneer 6
Vehicle: Delta E
Launch Date: 12/16/65
Mission: measure solar wind, solar magnetic field and cosmic rays
Outcome: Successfully achieved solar orbit and returned significant scientific data. There was a successful contact of Pioneer 6 for about two hours on 8 December 2000 to commemorate its 35th anniversary!.

Pioneer 7
Vehicle: Delta E
Launch Date: 8/17/66
Mission: measure solar wind, solar magnetic field and cosmic rays
Outcome: Successfully achieved solar orbit and returned significant scientific data. Transmitted data until September 1995, not quite 30 years.

Pioneer 8
Vehicle: Delta E
Launch Date: 12/13/67
Mission: measure solar wind, solar magnetic field and cosmic rays
Outcome: Successfully achieved solar orbit and returned significant scientific data. Still in solar orbit, no longer functional.

Pioneer 9
Vehicle: Delta E
Launch Date: 11/8/68
Mission: measure solar wind, solar magnetic field and cosmic rays
Outcome: Successfully achieved solar orbit and returned significant scientific data. Still in solar orbit, no longer functional.

Pioneer E
Vehicle: Delta L
Launch Date: 8/27/69
Mission: solar radiation measurements
Outcome: Hydraulics failure on launch, destroyed by range saftey officer.

Pioneer 10
Vehicle: Atlas Centaur
Launch Date: 3/3/72
Mission: Jupiter flyby
Outcome: Approached within 200000 km on December 3, 1973, returning a great deal of scientific data. First vehicle ot leave the solar system. Still alive after more than 30 years! As of this writing, last contact with the craft was 12/5/02.

Pioneer 11
Vehicle: Atlas Centaur
Launch Date: 4/6/73
Mission: Jupiter and Saturn flyby
Outcome: Approached within 34000 km of Saturn on December 4, 1974 and approached within 21000 km of Saturn on September 1, 1979. Also left the solar system.

Pioneer 12
Vehicle: Atlas Centaur
Launch Date: 5/20/78
Mission: Venus orbiter
Outcome: Successfully orbited Venus: mapped clouds, atmosphere and ionisphere and radar mapped 93 percent of the planet's surface.

Pioneer 13
Vehicle: Atlas Centaur
Launch Date: 8/8/78
Mission: Venus multiprobe
Outcome: Successfully delivered four atmospheric probes (one large, three small) to Venus. Although not designed to survive impact, one of the small probes did and it sent back measurements from the surface for 67 minutes. The carrier vehicle burned up on entry into the atmosphere.

Source: http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html