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Image credit: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

Origin of name
The Romans named the planet after their god of war.

Naming convention
Large craters: scientists who have contributed to the study of Mars, writers and others who have contributed to the lore of Mars. Large valleys: name for Mars or star in various languages.

ESA Mission
Mars Express


Mars Express
Mars Express, so called because of the rapid and streamlined development time, represents ESA's first visit to another planet in the Solar System. Borrowing technology from the Mars 96 mission and ESA's Rosetta mission, Mars Express is helping to answer fundamental questions about the geology, atmosphere, surface environment, history of water and potential for life on Mars.




Physical Properties


Property Unit Value Earth = 1
Equatorial radius km 3397 0.533
Polar radius km 3375 0.531
Core radius km 1700 0.488
Flattening   0.00648 1.934
Mass  (x1024) kg 0.64185 0.107
Volume  (x1010) km3 16.318 0.151
Mean density kgm-3 3933 0.713
Surface gravity at equator ms-2 3.71 0.379
Escape velocity kms-1 5.03 0.450
Magnetic dipole field at equator T < 10-8  
Number of natural satellites   2  


Orbital Parameters


Property Unit Value
Perihelion  (x106) km 206.62
Aphelion  (x106) km 249.23
Mean distance from the Sun  (x106) km 227.92
Mean distance from the Sun AU 1.524
Eccentricity   0.0935
Sidereal orbit period d 686.980
Sidereal rotation period h 24.6229
Length of day h 24.6597
Orbit inclination to Eliptic ° 1.850
Mean orbital velocity kms-1 24.13
Maximum orbital velocity kms-1 26.50
Minimum orbital velocity kms-1 21.97
Axial tilt ° 25.19


  • Sidereal orbit period
    The time taken by the planet to complete exactly one orbit around the Sun with respect to the celestial sphere.
  • Sidereal rotation period
    The time in which the planet rotates around its axis exactly 360° with respect to the celestial sphere.
  • Length of a day
    Defined as the time between two successive sunrises over the meridian.
  • Magnetic dipole moment
    Calculated as the ratio of the magnetic field strength at the equator divided by the cube of the equatorial radius.


Last Update: 1 September 2019
23-Jun-2024 01:01 UT

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