Mariner 2 spacecraft
Mariner 10 spacecraft
Mariner 2 spacecraft

Mariner 2 spacecraft

Courtesy of NASA

http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1962-041A



Overview
The Mariner program consisted of a series of 10 unmanned flyby missions launched by NASA between 1962 and 1973. These missions were designed to be the first to travel to other planets, specifically Venus, Mars, and Mercury. Seven were successful; three were lost. In summary:


Spacecraft

Destination

Launch year

Status

Mariner 1

Venus

1962

destroyed

Mariner 2

Venus

1962

flyby

Mariner 3

Mars

1964

lost

Mariner 4

Mars

1964

flyby

Mariner 5

Venus

1967

flyby

Mariner 6

Mars

1969

flyby

Mariner 7

Mars

1969

flyby

Mariner 8

Mars

1971

lost

Mariner 9

Mars

1971

flyby

Mariner 10

Venus, Mercury

1973

flyby


Goals
Fly by Venus and return data on the planet's atmosphere, magnetic field, charged particle environment, and mass. Make measurements of the interplanetary medium during the cruise to Venus and after the flyby.


Launch
August 27, 1962


Arrival
December 14, 1962 (closest approach)


End of Mission
January 3, 1963 (last communication)


Findings
Mariner 2 was the first spacecraft to successfully encounter another planet. Found Venus has a slow retrograde rotation rate, hot surface temperatures and high surface pressures, a predominantly carbon dioxide atmosphere, continuous cloud cover with a top altitude of about 60 km, and no detectable magnetic field. It was also shown that in interplanetary space the solar wind streams continuously and the cosmic dust density is much lower than the near-Earth region. Mariner 2 made improved estimates of Venus' mass and the value of the astronomical unit.