Upgrading from:

Miscellaneous`StandardAtmosphere`

All the functionality of Miscellaneous`StandardAtmosphere`is now available in the newly created Standard Atmosphere Package.

To access functionality from the new Standard Atmosphere Package, load StandardAtmosphere`:

Version 5.2 << Miscellaneous`StandardAtmosphere`;
MeanParticleSpeed[5000 Meter]
Standard Atmosphere Package

Many functions from Miscellaneous`StandardAtmosphere` are now found in the Standard Atmosphere Package:

AtmosphericPlot
CollisionFrequency
DynamicViscosity
GravityAcceleration
KinematicViscosity
KineticTemperature
MeanDensity
MeanFreePath
MeanMolecularWeight
MeanParticleSpeed
NumberDensity
Pressure
PressureScaleHeight
SoundSpeed
ThermalConductivityCoefficient