Phobos and Deimos, the moons of Mars - summary of findings

Mars has two very small moons. These are not library entities. These are bodies whose diameter is less than 30 km each, and if we use a figurative language, they are essentially flying mountains. In this respect they resemble asteroids and moons of this size that orbit the gaseous planets

introduction

Mars has two very small moons. These are not library entities. These are bodies whose diameter is less than 30 km each, and if we use a figurative language, they are essentially flying mountains. In this respect they resemble asteroids and moons of this size that orbit the gaseous planets.

Phobos

The dimensions of Phobos are 19 X 22 X 27 km, its distance from Mars is 5989 km and it orbits Mars once every 8 hours. An extremely unusual phenomenon since the duration of its orbit around Mars is less than the time it takes for Mars to rotate around its axis (24 hours and 37 minutes). The moon was photographed by spacecraft launched to Mars. These photographs were taken by taking advantage of the high eccentric point of their orbit around Mars, although often special maneuvers were performed to take these photographs. The spacecraft that photographed Mars are Mariner 7, Mariner 9, the Vikings, the Mars Global Surveyor. The Mars Express, the MRO and the Russian spacecraft Phobos 2. The combination of these photographs allowed the production of maps of the Moon. For comparison the first asteroid to be mapped is Eros imaged by the NEAR spacecraft entered orbit around it. This asteroid is slightly larger than Phobos. Its length is 33 km. The photos taken by the Mars Express on the 9th reached a particularly high resolution. 1. 2011. When this spacecraft passed at a distance of 100 km from it, it transmitted photographs to Israel with a resolution of 3 meters per pixel (7).

Measurements made by Mars Express showed that its density is 0 ± 02 g/cm1. A density lower than that of meteors and the meaning is that the moon is spongy with voids at a rate of 86% - 40% of the total volume of the moon (25). In this context, it is worth noting that already in 2 the astronomers Shkolovsky and Carl Sagan suggested that the moon is a hollow body (1960).

Phobos reflects 7-5% of the sunlight hitting it and its color is red (4). The large crater of the moon Stickney is dotted with many craters, although most of them are tens and hundreds of meters in size. A section of his language is blue (5). The number of craters that are larger than 1 km in diameter is 15 and the largest of them, Stickney, is 9 km in diameter (6). Considering the dimensions of Phobos, this is a very large crater. On the sides of the crater you can see dark and light stripes, which indicates rockfalls. At the bottom of the crater are partially buried rocks (7). Another phenomenon is a crater that lies on one of the sides of a Stickney crater and also has dark and light stripes. The surface of the moon is covered with a layer of dust 1 meter deep, probably due to the incessant bombardment of meteors (8). The thickness of this layer can be clearly seen in a number of craters adjacent to the Stickney crater.

There are many grooves on the moon in relation to its size. Their counterparts have not been found on any asteroid that has been photographed, nor on small moons of Saturn and Jupiter that have been photographed by spacecraft. Due to the dimensions of the moon it is hard to believe that these are tectonic processes. They can reach hundreds of meters and even kilometers in length. Some are parallel to each other and some go in and out of craters. The center of one of the grooves is filled with a layer of dust (9). The width of some of them reaches hundreds of meters (3).

Heat measurements made by the Mars Global Surveyor show that the temperatures depend on the slopes and the particle size and range from - 4 C to - 112 C in the shaded areas (10).

Phyllosilicate minerals were discovered northeast of Stikni Crater. The presence of this mineral raises a key question. These minerals interact with water and Phobos cannot have liquid water. The conclusion is required that the mother's body from which Phobos was detached contained water. Another possibility to explain the phenomenon, although on the face of it it is unlikely, is that the interior of the moon is warm enough to allow a long-term and stable presence of liquid water (2). So how did this mineral form on Phobos?

3 possibilities have been put forward to explain the origin of Phobos. According to one possibility it was originally an asteroid captured by the gravity of Mars. According to a second possibility, Phobos was formed at the same time as Mars. According to a third possibility, Phobos is the product of a giant meteorite impact on Mars. Rock fragments were thrown into space and stuck together (11).

In 1988, the Russians launched two spacecraft to Mars, Phobos 1 and Phobos 2. In April 1989, Phobos 2 was supposed to reach a distance of 30-80 meters from the moon and perform a formation flight with it for 15-20 minutes. The resolution of the cameras had to be 6 cm per pixel. Two landings were to be released later. One lander was static and intended to perform ground checks. The second landing was a hooper. It was designed to move from place to place by jumping while sampling the ground. The missions of both spacecraft failed. Phobos 1 managed to transmit several photographs of Mars and Phobos to Israel before losing contact with it (12, 13).

For a long time the Russians abandoned the exploration of Mars. This year, after several postponements, a Russian spacecraft will set off for Phobos. This spacecraft is called Phobos Grunt. This is a Russian Chinese European cooperation. Two spaceships will be launched to Mars next to each other. One spacecraft is Russian and the other spacecraft is Chinese and its purpose is to enter orbit around Mars and explore it. The Russian spacecraft will land on the moon and return soil samples to Israel. Choosing a suitable landing site will be based on the photos of the Mars Express. The landing should be in the area between W ° 235 – W ° 230 – N ° 5- S °5 (9, 14).

Demos

Demus is the small moon of Mars. Its dimensions are 12 x 16, its density is 1 grams cc and it orbits Mars once every 47 hours and 30. 17 minutes. It does not have prominent and unusual characteristics like the grooves of Phobos. The number of craters on its surface is very small and the diameter of the largest of them is Walter crater which is 9 km in diameter. Like Phobos it is also red and covered with a lot of dust. Its surface is smoother than that of Phobos and its origin is unclear (1). Its highest-resolution photo was taken by the Hawking spacecraft about 9. 15. 15. The spacecraft passed at a distance of 10 km from it and transmitted to Israel photographs with a resolution of 1977 meters per pixel. This required a complex series of maneuvers (48).

Sources

1 "The southern hemisphere of Phobos, up close" 24.1.2011
http://www.marsdaily.com/reports/ The_ Southern_ Hemisphere _Of _Phobos _Up_ Close_999.html

2."Martian moon Phobos may have formed by catastrophic blast" 23.9.2010
http://www.marsdaily.com/reports/ Martian_ Moon _Phobos_ May_ Have_ Formed_ By_ Catastrophic_ blast_999.html

3. Wilford JN-Mars Beckons p.76-78 Vintage Books 1969

4. New views of Martian moons
http://www.physorg.com/printnews.php?newaid=115483748

5. Phobos images by HiRISE (PSP_007769_9010)
http://huruse.lpl.arizona/edu/phobos.php

6. Gazetteer of planetary nomenclature. Phobos nomenclature craters

7.” Martian moon Phobos hip-deep in powder” 11.0.1998
http://mars.jpl.nasa.gov/mgs/images/mgsphotos.html

8. "Close inspection for Phobos" 1.5.2009
http://sci.esa.int/science-e/www/objectindex.cfm/objectid=31031

9. "Mars express acquires sharpest images of Martian moon Phobos" 30.7.2008
http://www.esa.int/esaMI/Mars_Express/SEM5H48N9JF_2.html

10. Mars Global Surveyor Mars Orbiter Camera
http://www.msss.com/mars/global-surv-images/9_11_98_photos_rel/index.html

11. "Phobos flyby season starts again" 17.10.2010
http://www.marsdaily.com/reports/ Phobos_ Flyby _Season_ Starts _Again_999.html

12. Zakharov AV–“Close encounters with Phobos” Sky and Telescope p.17 7/1988

13. Covault C.-"Soviet probe enters Mars orbit' landers to descend on Phobos"
Aviation Week and Space Technology p.24-25 13.2.1989

14. Covault C. – "Joint Russian and Chinese mission to Mars slips to 2011" 20.9.2009
http://www.spaceflightnow.com/news/n0909/19phobos/

15.Jones M.-"Don't forget Deimos" 13.9.2010
http://www.marsdaily.com/reports/ Don’t_ Forget _Deimos_999.html

16.http://antwrp.gsfc.nasa.gov/apod/images/9612/deimos_vik2_log.jpg