ESDU 77021 gives properties of a standard atmosphere to 1000 km. Tables give as a function of geopotential altitude in either ft or m up to 250 000 ft (80 km) values of temperature@ speed of sound@ pressure@ density@ kinematic and dynamic viscosities@ and thermal conductivity. Equations that can be readily programmed are also given for those properties as a function of altitude. A third table gives at geometric altitudes in m between 80 and 100 km values of temperature@ pressure@ density@ particle mean speed and mean free path@ and mean molecular mass. Graphs are also given plotting the difference between geopotential and geometric altitude as a function of geometric altitude in ft or m for altitudes to 250 000 ft (80 km) and sketches show the variation of all the properties with geometric height up to 100 km.