Chronology of Sun Exploration
Pioneer 5 - USA Solar Monitor - (March 11, 1959)
Space probe is now in a solar orbit.
Pioneer 6 - USA Solar Probe - 63.4 kg - (December 16,1965 - Present)
The Probe is still transmitting from solar orbit.
Pioneer 7 - USA Solar Probe - 63 kg - (August 17, 1966- ?)
Solar-orbiting probe was recently turned off.
Pioneer 8 - USA Solar Probe - 63 kg - (December 13,1967 - Present)
Solar probe is still transmitting from solar orbit.
Pioneer 9 - USA Solar Probe - 63 kg - (November 8, 1968- March 3, 1987)
This probe stopped functioning on March 3, 1987. It is still in solar orbit.
Skylab - USA Space Station - 91,000 kg - (May 14, 1973)
Skylab, which was America’s first space station, was manned for 171 days by three crews during 1973 and 1974. The space station included the Apollo Telescope Mount (ATM), which astronauts used to take more than 150,000 images of the Sun. Skylab was abandoned in February 1974 and re-entered the Earth’s atmosphere in 1979.
Explorer 49 - USA Solar Probe - 328 kg - (June 10, 1973)
Solar physics probe placed in lunar orbit.
Helios 1 - USA & West Germany Solar Probe - 370kg - (December 10, 1974 - 1975)
Solar probe is in a solar orbit; came within 47 million kilometers of the Sun.
Solar Maximum Mission - USA Solar Probe - (February14, 1980)
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 the Earth’s atmosphere on Dec. 2, 1989.
Helios 2 - USA & West Germany Solar Probe - (January16, 1976)
Solar probe came within 43 million kilometers of the Sun.
Ulysses - Europe & USA Solar Flyby - 370 kg - (October6, 1990)
The Ulysses spacecraft is an international project to study the poles of the Sun and interstellar space above and below the poles. It used Jupiter as a gravity assist to swing out of the ecliptic plane and onward to the poles of the Sun. The Jupiter flyby was on February 8, 1992. The first solar polar passage was in June 1994. The spacecraft passed the solar equator in February 1995 and passed over the north pole in June 1995.
Yohkoh - Japan Solar Probe - (August 31, 1991)
This spacecraft studied high-energy radiation from solar flares. The Japanese are undertaking this project in cooperation with the United States and Great Britain.
SOHO - Europe & USA Solar Probe - (December 12,1995)
The main scientific purpose of SOHO (Solar and Heliospheric Observatory) is to study the Sun’s internal structure, by observing velocity oscillations and radiance variations, and to look at the physical processes that form and heat the Sun’s corona and that give rise to the solar wind, using imaging and spectroscopic diagnosis of the plasma in the Sun’s outer regions coupled with in-situ measurements of the solar wind. SOHO will be put into a “halo orbit” around the L1 Lagrange point-the point 1.5 million kilometers away from us at which the gravitational pull of the Earth balances that of the Sun.