## About SpaceWorks Software

SpaceWorks Software develops technical and educational applications for the aerospace field and beyond. Our unique products and services are valued by government agencies, commercial companies, academic institutions, and private individuals around the world.

## Atmospheric Models

**1962/1976 U.S. Standard Atmosphere**
- At the altitudes covered by this calculator, the 1962 and 1976 U.S. Standard Atmospheres are identical. They are generally considered representative of mean conditions at 45° N latitude, and therefore are not the most accurate models possible for other locations.
**1963 Patrick AFB**
- This is a model that is adjusted from the U.S. Standard models to be directly representative of Cape Kennedy, Florida. Compared to the standard atmosphere, the Cape Kennedy temperatures are warmer in the troposphere and colder in the stratosphere.
**1971 Vandenberg AFB**
- This is a model that is directly applicable to Vandenberg Air Force Base. Compared to the standard atmosphere, the Vandenberg temperatures are warmer through most of the troposphere, become colder in the lower stratosphere, and then become warmer again in the rest of the stratosphere.

## Parameter Definitions

**Altitude**
- The height above mean sea level (MSL).

[ft or m]
**Calibrated Airspeed**
- Airspeed adjusted for pressure-altitude effect. Calibrated Airspeed gradually deviates from True Airspeed as altitude increases. Airspeed is typically measured using a pressure differential device called a pitot tube, and therefore is susceptible to variation at different altitudes.

[knots or m/s]
**Density**
- Ambient density value. Decreases as altitude increases.

[slugs/ft^{3} or kg/m^{3}]
**Dynamic Pressure**
- Pressure quantity equal to the product of one-half the density and the square of the velocity.

[lbs/ft^{2} or Pa]
**Mach Number**
- A non-dimensional parameter equal to the velocity divided by the local speed of sound. Named after Ernst Mach.

[no units]
**Temperature**
- Ambient temperature value. Decreases with altitude through the troposphere, remains constant through the lower stratosphere, and then increases through the remainder of the stratosphere. Additional changes in slope occur at higher altitudes beyond the range of this calculator.

[°R or K]
**Velocity**
- The rate of change of distance with respect to time. In this calculator, velocity is equivalent to True Airspeed.

[ft/s or m/s]

## Version Information

Version 2.0

Released in October 2020