Atmospheric Properties & Calculators

The design and operation of aerospace vehicles requires an understanding and quantification of the atmosphere and the impact on aircraft systems. The objective of this page is to provide a quick access to atmosphere theory and tools.

Standard Atmosphere at a Glance

The standard atmosphere is a useful tool for aircraft design and performance analysis. Notes are available here.

The atmosphere has not, is not, and never will be equivalent to the standard atmosphere. Non standard atmospheric standards are useful for quantifying flight performance in actual operating conditions. Notes on the canonical non-standard atmosphere is available here.

Airspeed

The atmosphere’s varying properties affect an aerospace vehicle’s flight systems. You can visually estimate the influence of airspeed and altitude with the following figure (pdf available here).

True airspeed [KTAS], calibrated airspeed [KCAS], dynamic pressure [q], temperature [F], total temperature [F], Mach number, and pressure [psi] versus altitude [ft]

Moist Air

The actual atmosphere contains more than just dry air. Water strongly drives micro to macro scale properties and events in the Earth’s atmosphere. A discussion is available here.

The following calculator determines moist air density given pressure, temperature, and relative humidity.

Pressure [psi]
Temperature [F]
Relative Humidity [%]
Density [slug/ft^3]