Physical Data

Planetary Properties

Orbital Properties

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      

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.