Back in the past - relief and climate.
Evidence for liquid water activity on Mars
Atmospheric composition Terraforming Mars


Results from exploration of Mars relief and climate
Exploration of the planet, give direction in hypothesis what the Mars climate was. ̉he present trend is climate to become drier. In contrast with present conditions a variety observations support the thesis that earlier the environment was much warmer, with higher temperatures and a major climatic change on Mars. Dispersed on the surface pebbles and cobbles, evidence for abundant sand-size particles observed at the Pathfinder landing site convince the scientist for former fluvial environment with liquid water in equilibrium with the environment. The newest data received June 22, was that there are evidences for underground flowing water 500 meters deep in the surface layer (more in part 2.). Dunes composite sand-size particles are formed on planet. Everyone knows very well generating of Earth sand, which is realized via fluvial processes. Other evidences are valleys, dry lakebeds found on Mars.
Martian surface layer is composite sand and dust. It is several tens of meters thick. Its particles are moved and deposited very fast - by 20mm/yr.Some areas are covered with huge piles of dust and they are very high. Others, like the Pathfinder landing site, characterize with smooth, open relief, evidence for wind erosion. Craters 46 high can be found.

The target is Mars!
Many of the key physical properties of Mars are remarkably similar to those of Earth. On both planets the length of day is about 24 hours --an important consideration for plants that have adapted to photosynthesize when the sun shines. Mars also experiences seasons, as the planet's axis is tilted to a similar degree as Earth's. Because Mars is farther from the sun, a Martian year is almost twice the length of an Earth year, but plants should be able to adapt to such a difference. One unalterable difference between Earth and Mars is gravity: Martian gravity is about one third that of Earth's. How life would adapt to reduced gravity is unknown. It is likely, however, that microbes and plants would adjust easily to Martian gravity, and some animals might cope just as well.


Mars/Earth Comparison

Bulk parameters

                                   Mars           Earth     Ratio (Mars/Earth)
Mass (1024 kg)                     0.64185         5.9736         0.107
Volume (1010 km3)                 16.318         108.321          0.151  
Equatorial radius (km)	           3397           6378.1          0.533
Polar radius (km)                  3375           6356.8          0.531
Volumetric mean radius (km)        3390           6371.0          0.532
Core radius (km)                   1700           3485            0.488
Ellipticity (Flattening)           0.00648         0.00335        1.93
Mean density (kg/m3)               3933           5515            0.713 
Surface gravity (m/s2)             3.69            9.78           0.377
Escape velocity (km/s)             5.03           11.19           0.450 
GM (x 106 km3/s2)                  0.04283         0.3986         0.107
Bond albedo                        0.250           0.306          0.817
Visual geometric albedo            0.150           0.367          0.409
Visual magnitude V(1,0)           -1.52           -3.86             -
Solar irradiance (W/m2)          589.2          1367.6            0.431
Black-body temperature (K)       210.1           254.3            0.826
Topographic range (km)               30             20            1.500
Moment of inertia (I/MR2)          0.366           0.3308         1.106
J2 (x 10-6)                     1960.45         1082.63           1.811 
Number of natural satellites          2              1
Planetary ring system                No             No

Orbital parameters

                                   Mars           Earth     Ratio (Mars/Earth)
Semimajor axis (106 km)          227.92          149.60           1.524
Sidereal orbit period (days)     686.980         365.256          1.881
Tropical orbit period (days)     686.973         365.242          1.881
Perihelion (106 km)              206.62          147.09           1.405       
Aphelion (106 km)                249.23          152.10           1.639
Synodic period (days)            779.94             -               -
Mean orbital velocity (km/s)      24.13           29.78           0.810 
Max. orbital velocity (km/s)      26.50           30.29           0.875
Min. orbital velocity (km/s)      21.97           29.29           0.750
Orbit inclination (deg)            1.850           0.000            -
Orbit eccentricity                 0.0935          0.0167         5.599
Sidereal rotation period (hrs)    24.6229         23.9345         1.029
Length of day (hrs)               24.6597         24.0000         1.027
Obliquity to orbit (deg)          25.19           23.45           1.074

Mars Observational Parameters

Discoverer:      Unknown
Discovery Date:  Prehistoric

Distance from Earth
        Minimum (106 km)           54.5
        Maximum (106 km)          401.3
Apparent diameter from Earth
        Maximum (seconds of arc)   25.7
        Minimum (seconds of arc)    3.5
Mean values at opposition from Earth
        Distance from Earth (106 km)         78.39    
        Apparent diameter (seconds of arc)   17.9
        Apparent visual magnitude            -2.0
Maximum apparent visual magnitude            -2.91

Mars Mean Orbital Elements (J2000)

Semimajor axis (AU)                  1.52366231  
Orbital eccentricity                 0.09341233   
Orbital inclination (deg)            1.85061   
Longitude of ascending node (deg)   49.57854  
Longitude of perihelion (deg)      336.04084   
Mean Longitude (deg)               355.45332

Martian Atmosphere

Surface Pressure:  ~6.1 mb (variable) [6.9 mb to 9 mb (Viking 1 Lander site)]
Surface Density: ~0.020 kg/m3
Scale height:  11.1 km
Average temperature:  ~210 K
Diurnal temperature range: 184 K to 242 K (Viking 1 Lander site)
Wind speeds:  2-7 m/s (summer), 5-10 m/s (fall), 17-30 m/s (dust storm) (Viking Lander sites)
Mean molecular weight: 43.34 g/mole 
Atmospheric composition (by volume): 
    Major      : Carbon Dioxide (CO2) - 95.32% ; Nitrogen (N2) - 2.7%
                 Argon (Ar) - 1.6%; Oxygen (O2) - 0.13%; Carbon Monoxide (CO) - 0.08% 
    Minor (ppm): Water (H2O) - 210; Nitrogen Oxide (NO) - 100; Neon (Ne) - 2.5;
                 Hydrogen-Deuterium-Oxygen (HDO) - 0.85; Krypton (Kr) - 0.3; 
		 Xenon (Xe) - 0.08

Satellites of Mars

                                    Phobos         Deimos
Semi-major axis* (km)                9378          23459
Sidereal orbit period (days)        0.31891        1.26244
Sidereal rotation period (days)     0.31891        1.26244
Orbital inclination (deg)            1.08           1.79
Orbital eccentricity                0.0151         0.0005
Major axis radius (km)                13.4            7.5
Median axis radius (km)               11.2            6.1
Minor axis radius (km)                 9.2            5.2
Mass (1015 kg)                       10.6            2.4
Mean density (kg/m3)                 1900           1750 
Geometric albedo                      0.07           0.08
Visual magnitude V(1,0)             +11.8          +12.89     
Apparent visual magnitude (V0)        11.3           12.40      

*Mean orbital distance from the center of Mars.


Back in the past - relief and climate.
Evidence for liquid water activity on Mars
Atmospheric composition Terraforming Mars