A key tracer used to estimate how much atmosphere Mars lost can change depending on the time of day and the surface temperature on the Red Planet. Earth’s atmosphere contains 400 ppm CO2 (0.04%). The surface pressure is 0.7% of earth's. The atmosphere is quite dusty, containing particulates about 1.5 µm in diameter which give the Martian sky a tawny color when seen from the surface. BUT, the gravity is only about 1/3 of earth. To help spacecraft designers, it is useful to define a mathematical model of the atmosphere to capture the effects of altitude. Atmosphere of Mars. Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is an engineering-level Mars atmosphere model widely used for many Mars mis-sion applications (Justus and Johnson, 2001; Justus et al., 2002a). Previous measurements of this tracer – isotopes of oxygen – have disagreed significantly. But Mars has surface temperatures that are about -75°C colder on average than Earth’s because atmospheric density, or pressure, is the “game changer” largely determining planetary temperatures. This presumably means a bottle of Mars atmosphere brought to earth (conserved at its original temperature and pressure) would weigh 3X as much as on Mars. Mars' spin rate and axial tilt are also Earthlike. The density of air or atmospheric density, denoted ρ (Greek: rho), is the mass per unit volume of Earth's atmosphere.Air density, like air pressure, decreases with increasing altitude. Although Mars' atmosphere used to be thick enough for water to run on the surface, today that water is either scarce or non-existent.

Physical properties of the Martian atmosphere. The information on the Martian atmosphere was gathered by Jonathon … There are intriguing clues that billions of years ago Mars was even more Earth-like than today. Aerodynamic forces directly depend on the gas density. MARTIAN ATMOSPHERE: Surface pressure: 6.36 mb at mean radius (variable from 4.0 to 8.7 mb depending on season) [6.9 mb to 9 mb (Viking 1 Lander site)] Surface density: ~0.020 kg/m 3 Scale height: 11.1 km Total mass of atmosphere: ~2.5 x 10 16 kg Average temperature: ~210 K (-63 C) Diurnal temperature range: 184 K to 242 K (-89 to -31 C) (Viking …

Mars’ modern atmosphere is only 1% the density of Earth‘s, but the planet’s watery phase is believed to have lasted for the first billion of its 4.5 billion years, which means its air must have been around that long too. Mars, fourth planet in the solar system in order of distance from the Sun and seventh in size and mass. Mars Observational Parameters Discoverer: Unknown Discovery Date: Prehistoric Distance from Earth Minimum (10 6 km) 55.7 Maximum (10 6 km) 401.3 Apparent diameter from Earth Maximum (seconds of arc) 25.1 Minimum (seconds of arc) 3.5 Mean values at opposition from Earth Distance from Earth (10 6 km) 78.39 Apparent diameter (seconds of arc) 17.9 Apparent visual magnitude -2.0 Maximum …