January 16, 1976 - Helios 2 - USA & West Germany Solar Probe
Solar probe came within 43 million kilometers of the Sun.

August 9, 1976 - Luna 24 - USSR Lunar Lander - 4,800 kg
The landing site was Mare Crisium at latitude 12°45' N and longitude 60°12' E. Samples amounting to 170 grams were returned from the moon.

August 20, 1977 - Voyager 2 - USA Jupiter/Saturn/Uranus/Neptune Flyby - 800 kg
Voyager 2 flew by Jupiter on July 9, 1979, Saturn on August 26, 1981, Uranus on January 24, 1986, and Neptune on August 24, 1989.

September 5, 1977 - Voyager 1 - USA Jupiter/Saturn Flyby - 800 kg
Voyager 1 flew by Jupiter on March 5, 1979, and Saturn on November 12, 1980.

May 20, 1978 - October 8, 1992 - Pioneer Venus 1 - USA Venus Orbiter - 582 kg
Pioneer Venus 1 (also known as Pioneer 12) arrived at Venus on December 4, 1978. It operated continuously from 1978 until October 8, 1992, when contact was lost with the spacecraft. It was expected to burn up in the Venusian atmosphere 6 days later. The orbiter was the first spacecraft to use radar in mapping the planet's surface. The electron field experiment detected radio bursts presumably caused by lightening. No magnetic field was detected. From 1978 to 1988 the amount of sulfur dioxide in the atmosphere decreased by 10%. The reason for this decrease is unknown. Perhaps a large volcano erupted just before the orbiter arrived and the amount of sulfur dioxide slowly declined.

August 8, 1978 - Pioneer Venus 2 - USA Venus Atmosphere Probe - 904 kg
Pioneer Venus 2 (also know as Pioneer 13) carried four atmospheric probes. One large and three smaller ones. They arrived at Venus on December 9, 1978 and plunged into the atmosphere. The four probes descended through the atmosphere by parachute while the spacecraft burned up high in the atmosphere. At a height of 70-90 kilometers the probes encountered a fine haze layer. Between 10-50 kilometers there was little atmospheric convection and below 30 kilometers the atmosphere was clear.

August 12, 1978 - International Sun-Earth Explorer 3 - USA Interplanetary Monitor - 479 kg
The Internation Sun-Earth Explorer was renamed to International Cometary Explorer (ICE). On September 11, 1985 it passed through the plasma tail of comet Giacobini-Zinner.

September 9, 1978 - Venera 11 - USSR Venus Flyby/Lander - 4,940 kg
Venera 11 landed on Venus on December 25, 1978, and returned data for 95 minutes. The imaging systems failed.

September 14, 1978 - Venera 12 - USSR Venus Flyby/Lander - 4,940 kg
Venera 12 landed on December 21, 1978 and returned data for 110 minutes. Electrical discharges, probably from lightning, were recorded.

February 14, 1980 - Solar Maximum Mission - USA Solar Probe
The Solar Maximum Mission (SMM) was designed to provide coordinated observations of solar activity, in particular solar flares, during a period of maximum solar activity. The spacecraft suffered an on-orbit failure. A repair mission on STS-41C in 1984, during which shuttle astronauts rendezvoused with SMM, was successful. SMM collected data until Nov. 24, 1989, and re-entered on Dec. 2, 1989.