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Mariner 6-7
Part of Mariner
Mariner 6, 7
Mariner 6, 7
Credit: NASA
American Mars flyby probe. Mariner 6 and 7 comprised a dual-spacecraft mission to Mars. Mars flyby satellite built by Jet Propulsion Laboratory (JPL) for NASA, USA. Launched 1969.

Status: Operational 1969. First Launch: 1969-02-25. Last Launch: 1969-03-27. Number: 2 . Gross mass: 412 kg (908 lb). Height: 3.35 m (10.99 ft).

The primary objectives of the missions were to study the surface and atmosphere of Mars during close flybys to establish the basis for future investigations, particularly those relevant to the search for extraterrestrial life, and to demonstrate and develop technologies required for future Mars missions and other long-duration missions far from the Sun. Each spacecraft carried a wide- and narrow-angle television camera, an infrared spectroscope, an infrared radiometer, and an ultraviolet spectroscope.

The spacecraft were oriented entirely to planetary data acquisition, and no data were obtained during the trip to Mars or beyond Mars. Mariners 6 and 7 were designed to fly over the equator and southern hemisphere of Mars. Mariner 6 encountered Mars on July 31,1969 and was quickly followed by Mariner 7 on August 4, 1969. The two spacecraft returned a combined total of 143 approach pictures of the planet and 55 close-up pictures. These images, from the vehicles' television cameras, included pictures of the northern and southern polar caps as well as Phobos, one of Mars' two moons. The spacecraft also studied the Martian atmosphere and profiled its chemical composition. Closest approach to Mars for both spacecraft was approximately 3,550 kilometers. The cost of the two missions was $148 million.

Spacecraft and Subsystems

The Mariner 6 and 7 spacecraft were identical, consisting of an octagonal magnesium frame base, 138.4 cm diagonally and 45.7 cm deep. A conical superstructure mounted on top of the frame held the high-gain 1 meter diameter parabolic antenna and four solar panels, each measuring 215 x 90 cm, were affixed to the top corners of the frame. The tip-to-tip span of the deployed solar panels was 5.79 m. A low-gain omnidirectional antenna was mounted on a 2.23 m high mast next to the high-gain antenna. Underneath the octagonal frame was a two-axis scan platform which held scientific instruments. Overall science instrument mass was 57.6 kg. The total height of the spacecraft was 3.35 m.

The spacecraft was attitude stabilized in three axes (referenced to the sun and the star, Canopus) through the use of 3 gyros, 2 sets of 6 nitrogen jets mounted on the ends of the solar panels, a Canopus tracker, and two primary and four secondary sun sensors. Propulsion was provided by a 223 N rocket motor mounted within the frame which used monopropellant hydrazine. The nozzle with 4-jet vane vector control protruded from one wall of the octagonal structure. Power was supplied by 17,472 photovoltaic cells covering an area of 7.7 square meters on the four solar panels. These could provide 800 W of power near Earth and 449 W at Mars. The maximum power requirement was 380 W at Mars encounter. A 1200 W-hr rechargeable silver-zinc battery was used to provide backup power. Thermal control was achieved through the use of adjustable louvers on the sides of the main compartment.

Three telemetry channels were available for telecommunications. Channel A carried engineering data at 8 1/3 or 33 1/3 bps, channel B carried scientific data at 66 2/3 or 270 bps and channel C carried science data at 16,200 bps. Communications were accomplished via the high- and low-gain antennas via dual S-band traveling wave tube 10/20 W amplifiers for transmission and a single receiver. An analog tape recorder with a capacity of 195 million bits could store television images for subsequent transmission. Other science data was stored on a digital recorder. The command system, consisting of a central computer and sequencer (CC&S), was designed to actuate specific events at precise times. The CC&S was programmed with a standard mission and a conservative backup mission before launch, but could be commanded and reprogrammed in flight. It could perform 53 direct commands, 5 control commands, and 4 quantitative commands.


The planetary experiments (59 kg) included two television cameras, an infrared radiometer, an infrared spectrometer, and an ultraviolet spectrometer. These sensors took TV pictures of Mars and measured the ratio of refractivity and UV and IR emissions of the atmosphere.

More at: Mariner 6-7.

Family: Mars flyby. Country: USA. Launch Vehicles: Atlas, Mars tactical rocket, Atlas SLV-3C Centaur. Projects: Mariner, Mars. Launch Sites: Cape Canaveral, Cape Canaveral LC36A, Cape Canaveral LC36B. Agency: JPL, NASA. Bibliography: 2, 278, 296, 3905, 6, 12796.
Photo Gallery

Mariner 6Mariner 6
Credit: Manufacturer Image

1969 February 25 - . 01:29 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC36B. LV Family: Atlas. Launch Vehicle: Atlas SLV-3C Centaur.
1969 March 27 - . 22:22 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC36A. LV Family: Atlas. Launch Vehicle: Atlas SLV-3C Centaur.
1969 July 31 - .
1969 July 31 - .
1969 August 4 - .
1969 August 5 - .

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