Documentation / @interstellar-tools/equations / atmosphericDragAcceleration

Function: atmosphericDragAcceleration()

function atmosphericDragAcceleration(
  Cd: number,
  A: number,
  m: number,
  rho: number,
  v: number
): number;

Defined in: orbits/atmospheric-drag-acceleration.ts:39

Compute atmospheric drag acceleration magnitude.

Equation:

$$a_D=\frac{1}{2}\frac{C_{D}A}{m}\rho v^2$$

Where:

• $C_D$ is the drag coefficient (dimensionless)
• $A$ is reference area normal to the flow (m²)
• $m$ is spacecraft mass (kg)
• $\rho$ is atmospheric density (kg/m³)
• $v$ is speed relative to the atmosphere (m/s)

Units:

• Returns acceleration magnitude in m/s².

Note:

• This returns the magnitude of drag acceleration. The drag acceleration vector points opposite the velocity direction (i.e., along $-\hat{v}$).

Parameters

Parameter	Type	Description
Cd	number	Drag coefficient $C_D$ (finite, >= 0).
A	number	Reference area $A$ (finite, >= 0), in m².
m	number	Mass $m$ (finite, > 0), in kg.
rho	number	Atmospheric density $\rho$ (finite, >= 0), in kg/m³.
v	number	Speed relative to the atmosphere $v$ (finite, >= 0), in m/s.

Returns

number

Drag acceleration magnitude $a_D$ in m/s².

Throws

If any input is not finite.

Throws

If m <= 0 or any of Cd, A, rho, v is negative.

Example

// Example (rough LEO order-of-magnitude):
const aD = atmosphericDragAcceleration(2.2, 2.0, 500, 1e-12, 7700);