Pioneer 6 Credit - NASA

Pioneers 6, 7, 8, and 9 were created to make the first detailed, comprehensive measurements of the solar wind, solar magnetic field and cosmic rays. The vehicles acted as the world's first space-based solar weather network, providing practical data on solar storms which impact communications and power on Earth.

The satellites were designed to measure large scale magnetic phenomena and particles and fields in interplanetary space. Data from the vehicles were used to better understand stellar processes as well as the structure and flow of the solar wind. A fifth spacecraft, Pioneer E, was lost when it failed to orbit due to a launch vehicle failure. The Pioneer 6-9 program was touted as one of the least expensive of all NASA spacecraft programs in terms of scientific results per dollar spent. As of 1996, Pioneer 6 was NASA's oldest operational satellite, having been in orbit over 30 years. The spacecraft was spin stabilized at ~60 rpm. Body mounted solar cells provided 79 watts. The payload consisted of six instruments, including a Plasma Analyzer and Cosmic Ray Detector.

Design Life: 6 months. Typical orbit: Solar orbits, between 0.8 and 1.2 AU. Length: 0.81 m (2.65 ft). Maximum Diameter: 0.94 m (3.08 ft). Mass: 64 kg (141 lb).

• 1965 December 16 - Pioneer 6 - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 63 kg (138 lb).
  Measured solar wind, Sun's magnetic field. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1966 August 17 - Pioneer 7 - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Mass: 63 kg (138 lb). Perigee: 246 km (152 mi). Apogee: 993 km (617 mi). Inclination: 33.00 deg. Period: 97.20 min.
  Monitored solar wind, cosmic rays. SOLAR ORB. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1967 December 13 - Pioneer 8 - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 63 kg (138 lb).
  Solar radiation data. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1968 November 8 - Pioneer 9 - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC17B. Launch Vehicle: Delta. Mass: 63 kg (138 lb).
  Solar radiation data. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1969 August 27 - Pioneer E - Program: Pioneer. Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. FAILURE: First stage hydraulics failure. Vehicle destructed at T+383 seconds. Mass: 67 kg (147 lb).