MARS, RETURN TO THE RED PLANET

The whole disc of Mars photographed by the Viking probe. (JPEG, 282 K)  (NASA-JPL)

The temperatures measured by the landing modules of the Viking probes are comparable with those of Antarctic, between -80 and -30 degrees. The polar regions are covered with caps of ice, while large amounts of dust are carried by winds that can reach 200 km/h. A complex of canyons crosses about one quarter of the circumference of the planet, reaching the depth of 6 km, while the highest mountain of the Solar System, Mount Olympus, is 24 km high. Nontheless Mars is the planet whose environmental conditions are the most similar to those of the Earth, and some futurist projects suggest the possibility of massive interventions in order to modify such conditions for a possible colonization.
 

Some structures of the surface, interpreted as ancient river beds, allow to speculate over a past in which Mars maybe had a more dense atmosphere, milder temperatures and water in the liquid phase. Will it be possible, for the future missions, to find traces, even fossil ones, of martian life?
 

The two Viking probes were launched from the Kennedy Space Center in Florida in 1975. Their goal was to study Mars in orbit, and to disembark two landing modules on the surface of the planet to study its composition and to look for any form of life. The landing modules, here you can see one of them, touched the Martian soil in 1976, in two flat areas. The probes sent to Earth a total of 56,000 photos. The last transmission dates back to 1982. due sonde Viking furono lanciate dal Kennedy Space Center in Florida nel 1975. (JPEG, 419 K) (NASA-JPL)

 

Mars in opposition photographed by Hubble Space Telescope in 1995. Spots of clouds and the large quantity of ozone detected in the atmosphere indicate that the climate has changed considerably in the last two decades. (JPEG, 192 K) (NASA-STScI)

 

The Utopia Planitia region of the planet photographed by Viking II. You can see desolate expanses of sand covered with stones and rocks of various size. There is a dominant reddish colour not only in the soil but also in the martian sky, due to the suspension of dust. (JPEG, 121 K) (NASA-JPL)

 

The northern hemisphere of the planet in a picture of the Viking that shows in the centre the complex of canyons called Valles Marineris, and on the left two large vulcanos of the Tharsis region. (JPEG, 50 K) (NASA-JPL)

 

Mount Olympus, with the peak covered with snow, is a vulcano that reaches a height that is three times that of our Everest. It is the major mountain formation known in the entire Solar System. It has the same structure as the shield vulcanos of the Hawaii, although it is much larger. (JPEG, 71 K) (NASA-JPL)

 

Close-up of Phobos, one of the two satellites of Mars. They are both small rocky bodies, with a radius of a few kilometres, maybe asteroids that travelled in the vicinity of the planet and were captured. Their surface is covered with craters. (JPEG, 29 K) (NASA-JPL)

 

Winter vision of the martian surface, photographed by the landing module of Viking II. On Mars, as on the Earth, the seasons alternate due to the inclination of the rotation axis of the planet. Their duration though is twice that of the Earth. The coat of ice that covers the soil is solified carbon dioxide. Water ice is very scarce and is concentrated in the polar caps. (JPEG, 347 K) (NASA-JPL)

 

The Viking landing module dug grooves in the ground, that are visible on the right, to collect samples of martian soil to be analyzed. The experiments carried out to search for forms of life, at least of the bacterial type, were disappointing, although the results were not completely clear. We expect more precise and maybe enthusiastic answers from the future missions on Mars. (JPEG, 76 K) (NASA-JPL)

 

Sunset on Mars. The day here lasts 24 hours and 37 minutes, and is therefore very similar to the terrestrial day. The martian sky is almost always clear, with rare cloud formations, although sometimes it becomes turbid due to the sand raised by the wind. The atmosphere is very thin with a pressure on the ground of 5 millibars approximately (1013 millibars on the Earth) and water does not remain in the liquid phase on the surface, but it freezes or it evaporates, depending on the temperature. (JPEG, 45 K) (NASA-JPL)

 
 

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