  ADBSat is a novel software that determines the aerodynamic properties of any
body in free-molecular flow. Its main advantage is the fast approximation of
the aerodynamics of spacecraft in the lower end of the low-Earth orbit altitude
range. It is a novel implementation of a panel method, where the body is
represented as a set of fundamental elements and the sum of their individual
aerodynamic properties makes up the properties of the whole. ADBSat's approach
treats the shape as a set of flat triangular plates. These are read from a CAD
geometry file in the Wavefront format, which can be created with most common
CAD programs. A choice of gas-surface interaction models is available to
represent the physics of free-molecular flow under different conditions. Its
modular design means that other models can be easily and quickly implemented.
It also benefits from a new shading algorithm for fast determination of
elemental flow exposure. The flat plate representation and shading algorithm
are further employed to determine solar coefficients, again with the ability to
easily add further solar radiation pressure models as they become available. An
example case is presented to show the capability and functionality of the
program.
