August 27, 1962 – Mariner 2 is launched

NASA copy –

Launch (Mariner 2): August 27, 1962
Flyby (Mariner 2): December 14, 1962
Mass: 203 kilograms (447 pounds)
Science instruments: Microwave radiometer, infrared radiometer, flux-gate magnetometer, ion chamber and Geiger-Mueller counters, cosmic dust detector, solar plasma detector


As plans were getting under way to explore the Moon with the Rangers and Surveyors, JPL and NASA also turned their attention to the rest of the solar system. The Mariner series of missions were designed to be the first U.S. spacecraft to other planets, specifically Venus and Mars. Mariner 1 and 2 were nearly identical spacecraft developed to fly by Venus. The rocket carrying Mariner 1 went off-course during launch on July 22, 1962, and was blown up by a range safety officer about 5 minutes into flight.

A month later, Mariner 2 was launched successfully on August 27, 1962, sending it on a 3-1/2-month flight to Venus. On the way it measured for the first time the solar wind, a constant stream of charged particles flowing outward from the Sun. It also measured interplanetary dust, which turned out to be more scarce than predicted. In addition, Mariner 2 detected high-energy charged particles coming from the Sun, including several brief solar flares, as well as cosmic rays from outside the solar system.

As it flew by Venus on December 14, 1962, Mariner 2 scanned the planet with infrared and microwave radiometers, revealing that Venus has cool clouds and an extremely hot surface. (Because the bright, opaque clouds hide the planet�s surface, Mariner 2 was not outfitted with a camera.)

Mariner 2’s signal was tracked until January 3, 1963. The spacecraft remains in orbit around the Sun.


Mariner 2 (Mariner-Venus 1962), a space probe to Venus, was the first successful spacecraft in the NASA Mariner program. The Mariner 1 and 2 spacecraft were simplified versions of the Block I spacecraft of the Ranger program.

The Mariner probe consisted of a 100 cm diameter hexagonal bus, to which solar panels, instrument booms, and antennas were attached. The scientific instruments onboard the Mariner spacecraft were two radiometers (microwave and infrared) mounted on a tilting platform, a micrometeorite sensor, a solar plasma sensor, a charged particle sensor, and a magnetometer. These instruments were designed to measure the temperature distribution on the surface of Venus, as well as making basic measurements of Venus’ atmosphere. Due to the planet’s thick, featureless cloud cover, no cameras were included in the Mariner units. (Mariner 10, a distant cousin of Mariner 2, later discovered that extensive cloud detail was visible in ultra-violet light.)


National Air and Space Museum Image Detail

Mariner 2

On December 14, 1962, useful scientific information was radioed to Earth from the vicinity of another planet for the first time. The unmanned Mariner 2 spacecraft, with its six scientific instruments, passed within 34,800 kilometers (21,600 miles) of Venus. Mariner 2 indicated that Venus is very hot and has no measureable magnetic fields or radiation belts. On the way to Venus, Mariner 2’s instruments detected and measured the radiation, magnetic fields and dust of interplanetary space.

Mariner 2


~ by tellinghistory on August 27, 2007.

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