Planetary Properties

Orbital Properties

Mass (10²⁴ kg)

0.64185

Semi-major axis (10⁶ km)

227.92

Volume (10¹⁰ km³)

16.318

Sidereal orbit period (days)

686.980

Equatorial radius (km)

3397

Tropical orbit period (days)

686.973

Polar radius (km)

3375

Perihelion (10⁶ km)

206.62

Volumetric mean radius (km)

3390

Aphelion (10⁶ km)

249.23

Core radius (km)

1700

Synodic period (days)

779.94

Ellipticity (Flattening)

0.00648

Mean orbital velocity (km/s)

24.13

Mean density (kg/m³)

3933

Max. orbital velocity (km/s)

26.50

Surface gravity (m/s²)

3.69

Min. orbital velocity (km/s)

21.97

Escape velocity (km/s)

5.03

Orbit inclination (deg)

1.850

Solar irradiance (W/m²)

589.2

Orbit eccentricity

0.0935

Black-body temperature (K)

210.1

Sidereal rotation period (hrs)

24.6229

Topographic range (km)

30

Length of day (hrs)

24.6597

Number of natural satellites

2

Obliquity to orbit (deg)

25.19

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 centre of Mars.