Project Mariner Chapter 2 - Mariner Spacecraft to Mars (1)

After the two launches to Venus, NASA directed the next Mariner spacecraft to Mars, the project started with a malfunction, the first of many, but this did not stop them from continuing. In this episode we will tell the story of the Mariner 3,4,6,7 spaceships

Mars from the perspective of a hot air balloon
On March 1, 1963, a hot air balloon was launched from Texas to a height of 22.47 km. The purpose of the launch was to find signs of life on Mars. The balloon had two telescopes with a diameter of 91.44 cm each and they found that there are signs of water and CO2 on the surface of Mars. 12 hours after the launch on March 2, the ball landed.

Mariner 3
After two launches to Venus, the third spacecraft in the Mariner series, Mariner 3, was launched to Mars. The launch was on November 5, 1964 and the duration of the flight was eight and a half months. 30 minutes before passing by it, 13,840 km from Mars, the spacecraft was supposed to transmit 22 images of it to Israel. The spacecraft weighs 261 kg and was launched by the Atlas Agena D launcher. In addition to the cameras, the spacecraft had other research instruments that were supposed to find out if there was life on it. The mission failed when the spacecraft's solar arrays did not deploy. The power source was lost and as a result contact with the spaceship was lost.
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Mariner 4
The spacecraft was launched on November 28, 1964 and had three objectives:
A. Broadcast 22 photographs of the surface of Mars.
B. Measure the atmospheric pressure of Mars.
third. To obtain information about the interstellar space between Mars and Earth.
The spacecraft is built from a central octahedral magnesium body and around it are four solar racks that provide energy for its computer. The spacecraft contains a TV camera, a cosmic ray telescope and more. The main engine is powered by hydrazine. Her weight is 260 kg. The launcher was Atlas Agena D. The spacecraft traveled 523 million km.
The spacecraft's engineers estimated that there would be deviations from the flight path and they were indeed corrected. A few days after the launch an unsuccessful navigation maneuver was made. The reference star by which the spacecraft steers itself is Canopus. Upon receiving the first command, the spaceship turned on its axis and another star was discovered that is less powerful. To correct the deviation a new instruction was given, one hour and 40 minutes after the deviation was discovered, the spacecraft returned to its reference star. The spacecraft has two antennas. One is aimed at Canopus and the other at Earth. The information was broadcast to Israel when both antennas were in place.
In March 1965, additional minor repairs were made. An electronic measuring device was activated to measure the hot gases emitted from the sun. No significant malfunctions were discovered during the flight. However, two of the seven instruments intended for scientific observations stopped working. One of them is designed to measure the energy supply in the spacecraft. Even without these instruments, the spacecraft could have completed its main task, photographing Mars.

On July 14, 1965, the spacecraft received a signal to activate the mechanism that allows the cameras to search for targets, 10 minutes after the spacecraft passed the surface of Mars. The incoming signals were contradictory and there was concern that the recording tapes were not working properly. The conflicting signals were received for 40 minutes and alternately announced regular and irregular operations of the devices. It was feared that the spacecraft had failed in its mission. It was a false fear. All 22 planned pictures were broadcast to Israel.

The spacecraft cameras took pictures when the spacecraft was at a distance of 9,846 km from the ground of Mars. Decoding each photograph required many hours of transmission and reception. Only when all the signals carrying the parts of each photograph were captured and decoded, could its nature be determined. Each photograph is decomposed into 40,000 points. At each point, the range of error in the light intensity is calculated according to the data of the camera lens. The corrected light intensity data was recorded on magnetic tape and transferred to a computer for processing. According to the instructions given to him, he created photographs for various needs. In some photographs, the contrast of black and white was increased and thus the shape of the objects on the surface was highlighted. With the help of these methods they were able to distinguish details that were not clearly visible before. For example, 100 craters of volcanoes were visible in the original photographs, while after the further development, 300 craters similar to those found on the surface of the moon are visible, although the progressive effect of erosion is evident in them. The slope of the slopes of the mouths is less steep and the height of the margins is also not great. Probably under the influence of the Martian atmosphere which causes the gradual erosion of prominent objects in the area. The photographs show lines 300-150 km long that look like ridges or valleys. These are probably fracture zones in the outer crust of Mars.

On the edges of the craters located near the edge of the South Pole are rings that are bright white in color. These rings are incomplete in their northwestern part. It was assumed that the white color was a thin coating of dry ice. By combining the first three photographs, a picture of a vast desert area was obtained, bathed in the bright light of the midday sun in the cloudless Martian sky. In the photographs, craters and valley-like depressions were discovered instead of the expected canals. In the second photo, taken during the 25 minutes that the spacecraft passed the surface of Mars, you can see depressions casting shadows similar to canyons on Earth and they are surrounded by sharp peaks. In the third photo you notice a depression, probably a crater with a diameter of 20 km. The first three photographs cover a strip of land 1,000 km long.

The original plan was not prepared with the calculation that all the photographs would overlap. The line of thought was to get photos in pairs. One photo was taken with a green filter and the other with a red filter. Due to errors in estimating the spacecraft's flight path compared to the orbit of Mars, the spacecraft was at a distance that differed by 800 km from the point set in the original plan. This may be the reason for the inclusion of wider areas in all the images, and because of this they would have overlapped with the photographs taken and received up to that time. The error in the estimate was attributed to poor knowledge of the size of the solar system. They also caused some to make a mistake regarding the orbit of Mars that had been discovered until then. Not a single photograph from this series of photographs showed a straight line when looking at the Earth, they assumed it was a configuration of canals.

The rest of the photographs show 70 craters of various diameters, starting with those with a diameter of 5 km and ending with those with a diameter of 120 km. From all the photographs you can see that the surface of Mars is tattooed with craters to a large extent reminiscent of the surface of the moon. The areas subject to the green color changes are particularly rich in craters. All the photographs taken by Mariner 4 were broadcast in Israel from July 5 to 14. The spacecraft covered 1% of the surface of Mars in its photographs. Based on the photographs, it was determined that the number of craters with a diameter of 5-120 km can reach 30,000, almost as many as the number of craters on the moon. Geologically, Mars is inactive. The changes applied to its surface are the result of meteorite bombardment only. Atmospheric pressure is very small, 1/30 that of the Earth. The atmosphere is mainly made of 2 CO with very little oxygen, hydrogen and very little water. The radiation belts surrounding Mars are much weaker than the Van Allen belts. Mars has a small magnetic field. On its way to Mars, the spacecraft tested magnetic fields, the solar wind, cosmic radiation and micro meteorites.

Mariner 4 has proven very reliable. Two and a half years after it completed its mission when it was 90 million km from Earth, in the months of August - October 1967, its engines and systems were activated again. It was at a time when the sun's activity was strong. This was once Mariner 4, Mariner 5 and Earth were in an imaginary straight line leading to the Sun. The distance between the spacecraft was 110 million km. This situation made it possible to simultaneously perform measurements at three points of the movement of the solar wind and of the sun's magnetic field lines. Mariner 4 retransmitted the photographs of Mars recorded on its magnetic film.
Mariner 6, Mariner 7
Two spacecraft launched by the United States in 1969 to Mars, these were Mariner 6 and Mariner 7. The goal was to study the surface of Mars and its atmosphere in order to create a basis for future experiments regarding the search for life outside the Earth. The researchers wanted to know if there is water on Mars in the form of ice and if the seasonal changes on its surface moving from the poles to the equator are related to the melting of the ice and can stimulate primitive vegetation. Another goal was to develop technology that would enable missions that include launching spacecraft to alternate near Mars, and more advanced spacecraft to land on its surface.

Mariner 6 and Mariner 7 were more sophisticated than Mariner 4 and more capable. Each spacecraft weighed 413 kg. Each one was constructed from a central octahedral magnesium body with eight compartments containing electronic equipment, a base for television cameras and four sun racks each 2.13 meters long. At the ends of the shelves there are navigation engines. The height of the spacecraft is 3.35 meters. The launcher used for this purpose is Atlas Centauri.
The investigation of Mars was done on several levels:

1. Photography - each spacecraft has two cameras that operate alternately to photograph small and large areas of Mars in low and high resolutions. The cameras are equipped with filters designed to show the color differences in different details of the surface. The cameras have a resolution of 27 and 100 meters and are mounted on a rotating surface.

The two spacecraft broadcast over 100 photographs to Israel. The transmission speed was greater than that of Mariner 4. While Mariner 4 transmitted eight items per second, the transmission speed of these spacecraft was 16,000. Since the television cameras could pick up details with great resolution, they were 16 times more detailed than those of Mariner 4. The photographs arrived in Israel every 5 minutes. As soon as a photograph was received by the spacecraft's television equipment, it was quickly translated into electronic signals of varying intensity that represented 64 shades from white to black. These signals were broadcast to Israel in the binary language of the computers. To complete one photograph, the spacecraft's instruments had to scan 665,208 points of light or darkness, each of which was converted into six data marks for the computer. The Mariner 4 equipment needed 8.5 hours to create a less detailed photograph. After the signals were picked up by the NASA antenna at Goldstone (Mohabbi Desert), they were translated back into points of light or darkness by the Unibek 1219 computer, line by line.

2. Spectroscopic analysis
A. Each spacecraft had an infrared spectrometer designed to check if there is evidence of the existence of molecules of significance in biochemical processes at the bottom of the atmosphere.
B. An ultraviolet spectrometer for identifying the components of the atmosphere at an altitude of 90-160 km from the ground.
third. An infrared radiometer for measuring the different temperatures on the surface of the ground, drawing infrared maps and comparing them with the photographs. Such a comparison helped clarify the question of whether the ice caps contain water or 2CO.
d. A device for testing the deviations of radio signals transmitted from the spacecraft during their passage on the other side of Mars. These tests also helped in measuring the pressures and density of the atmosphere.

The spacecraft tracking data was used to determine the mass of Mars, to determine the ratio between the mass of Mars and that of the Moon, to determine the exact distance between the Earth and Mars and to determine the astronomical unit more precisely. The spacecraft's instruments could detect the existence of chemical substances such as water, 2CO, ethylene and acetylene down to tiny concentrations of 1,000,000 /2. The atmospheric pressure measured was 1/200 that of Earth. 98% of the content of the atmosphere is 2CO. Mariner 6 and Mariner 7 covered 20% of the surface of Mars in their photographs. The craters of Mars differ from those of the Moon due to the influence of the wind and dust that cause their wear.

The truth of relativity

The theory of relativity says that the speed of light decreases when it passes through the sphere of influence of the Sun's gravity. It was decided to use these flights to test its authenticity. The instruments of the spacecraft were used to test this claim. After completing their mission, they were put into orbit around the sun. When they were on the other side of the sun and their distance from the earth was 400 million km from the earth, signals from the earth were transmitted to them. These signals activated several instruments on the spacecraft that transmitted them back to the tracking station on Earth. Measurements made in relation to their speed proved that the Sun's gravity has an effect on the radio waves, and indeed the speed of these waves slowed down when they entered the Sun's gravitational field.

Mariner 6

Mariner 6 was launched on February 24, 1969 and arrived there on July 28, the date it made its transit flight. The spacecraft traveled a distance of 387.8 million km in 156 days.

The spacecraft transmitted 74 photographs in two sequences:
First sequence - in this sequence photographs were broadcast for 20 minutes. The first photograph was taken from a distance of 1.25 million km from Mars and the last from a distance of 104,000 km from it. In this photograph the surface and the ice poles are clearly visible. The photos are less bright than they hoped. However, it is possible to clearly distinguish two spots that look like clouds as well as a row of deep grooves in the South Pole.
Second sequence - this sequence is done when the spacecraft flies parallel to the equator and at a distance of 3,428 km from the ground.
Photo number 1 - an unidentified stain is visible. Because of the bright polar ice cap on the right, the spot looks like the pupil of the eye.
Photo number 3 - the Cyrene Sea
Photo number 4 - Narcissus Peak
Photo number 6 - between the equator and the South Pole a dark spot is visible. It was suggested that there is vegetation in this area.
Photo number 7 - Paintuntis desert. Due to malfunctions in the reception equipment on Earth, photograph number 11 and part of photograph number 12 were initially received. After the malfunction was repaired, the photographs were broadcast once more.
Photo number 11 - you can see a light spot on the western side. This spot was identified as the "cloud of Mars".
Photo number 20 - after it was enlarged 4 times it became clear that the lips of the South Pole dome are dismembered. Without magnification, the lips look like a sharp circle.

In other photographs, new indistinct formations are visible. These formations were assumed to be clouds. The equatorial region is similar to the moon. It turned out that Nix Olympia is not a huge crater as thought until now, but a volcano that rises to a height of 27 km and the diameter of the crater at its summit is 64 km. In one of the photographs we can see a straight route. No signs of canals were found in some places on the ground. The surface of the ground is different from those of the Earth and the Moon. In an area of ​​750,000 square kilometers, the ground surface is similar to places after an earthquake. The spacecraft findings showed some evidence of ice and water vapor in the atmosphere. The atmosphere is thin and has no nitrogen. The ground is constantly bombarded with ultraviolet radiation. The temperature on the ground ranges from 73 degrees below zero to 24 degrees.

Mariner 7
The spacecraft was launched on March 27, 1969 and was also intended to pass by Mars. During its flight it deviated several times from its course and by signals from the earth it was returned to the planned flight route. On July 30, a meteorite hit her. Some devices were indeed damaged, but this did not prevent her from fulfilling her mission to the best of her ability. The photos were of the highest quality. Mariner 7 traveled 317 million km in 130 days.

After one of the signals was lost, another instruction was broadcast to activate the antenna. The relationship was renewed. It turned out that the meteorite impact caused the loss of several telemetry channels. A slight change in flight speed resulted in a 10 second delay of the transition flight. While Mariner 6 passed over the equator, Mariner 7 focused on the Southern Hemisphere and part of the polar ice cap. The crossing distance was 3,540 km.

The spacecraft began filming on July 2 from a distance of 1,126,540 km. These photographs were broadcast on the same day. On July 4, 32 photographs were broadcast, eight times more than planned. Initially, the photographs show a black line in the center as well as gray areas, due to the fact that the computer operations were not completed until then. On July 6, the broadcast of the photographs stopped from time to time. The spacecraft transmitted 126 photographs.

The advantage of these photographs was due to the fact that the temperature inside the spaceship was several degrees higher, which allowed the signals transmitted from it to be stronger. In the photographs you can see ice-filled craters on the edge of the South Pole dome. The ice cap is mostly dry ice with a small water content. Near the pole is an orange colored desert area with craters. Geological formations similar to human footprints were also discovered. Methane and ammonia, which are the source of the development of the chain of life on Earth, were discovered above the pole.

• Project Mariner Chapter 1: Mariner spacecraft launched to Venus
• Mars exploration in Russia 1962-1974

In the next episode - Mariner 8 and 9 and in the episode after that - Mariner spacecraft to the planet Hema