Author Topic: Mariner 6 & 7 Mars Mission: "Mariner Mars '69" 1969 NASA JPL  (Read 425 times)

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Mariner 6 & 7 Mars Mission: "Mariner Mars '69" 1969 NASA JPL; Martian Probe Spacecraft

Jeff Quitney
Published on Sep 13, 2017


As part of NASA's wider Mariner program, Mariner 6 and Mariner 7 (Mariner Mars 69A and Mariner Mars 69B) completed the first dual mission to Mars in 1969. Mariner 6 was launched from Launch Complex 36B at Cape Canaveral Air Force Station and Mariner 7 from Launch Complex 36A at Cape Kennedy. The craft flew over the equator and south polar regions, analyzing the atmosphere and the surface with remote sensors, and recording and relaying hundreds of pictures. The mission's goals were to study the surface and atmosphere of Mars during close flybys, in order 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. Mariner 6 also had the objective of providing experience and data which would be useful in programming the Mariner 7 encounter five days later.

Mariner 6 lifted from LC-36B at Cape Canaveral on February 25, 1969, using Atlas-Centaur AC-20 and Mariner 7, from LC-36A on March 27, using AC-19.

Spaceflight

On July 29, 1969, less than a week before closest approach, Jet Propulsion Laboratory (JPL) lost contact with Mariner 7. The center regained the signal via the backup low-gain antenna and regained use of the high gain antenna again shortly after Mariner 6's close encounter. Leaking gases from a battery (which later failed) were thought to have caused the anomaly. Based on the observations that Mariner 6 made, Mariner 7 was reprogrammed in flight to take further observations of areas of interest and actually returned more pictures than Mariner 6, despite the battery's failure.

Closest approach for Mariner 6 occurred July 31, 1969, at 05:19:07 UT at a distance of 3,431 kilometres (2,132 mi) above the martian surface. Closest approach for Mariner 7 occurred August 5, 1969 at 05:00:49 UT[2] at a distance of 3,430 kilometres (2,130 mi) above the martian surface. This was less than half of the distance used by Mariner 4 on the previous US Mars flyby mission.

Both spacecraft are now defunct in heliocentric orbits.

By chance, both spacecraft flew over cratered regions and missed both the giant northern volcanoes and the equatorial grand canyon discovered later. Their approach pictures did, however, photograph about 20 percent of the planet's surface, showing the dark features long seen from Earth, but none of the canals mistakenly observed by ground-based astronomers. In total 201 photos were taken and transmitted back to Earth, adding more detail than the earlier mission, Mariner 4. Both craft also studied the atmosphere of Mars.

Coming a week after Apollo 11, Mariner 6 and 7's flyby of Mars received less than the normal amount of media coverage for a mission of this significance.

The Mariner 6 and 7 spacecraft were identical, consisting of an octagonal magnesium frame base, 138.4 cm (54.5 in) diagonally and 45.7 cm (18.0 in) 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 (35 in), 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 (127 lb). The total height of the spacecraft was 3.35 m.

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Originally a public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://www.youtube.com/watch?v=9415uzNKQXA?t=001

Tony De La Rosa

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