Mars

## Mars

 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

### Notes

• 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

## ShortUrl Portlet

Shortcut URL

https://sci.esa.int/s/WXmVaX8