Source: https://ntrs.nasa.gov/api/citations/20110007876/downloads/20110007876.pdf
Theory: Sunlight has momentum. An object absorbing sunlight absorbs the momentum, causing a pressure force. If the sunlight is reflected exactly along its path (i.e. mirror), pressure force is felt twice as much.
Type: Cyclic
Calculation:
Starting estimate, assuming uniform reflectance
$$ T_s=\frac{\Phi}{c}A_s(1+q)(cp_s-cm)\cos{\phi} $$
$T_s$ is SRP torque
$\Phi$ is the solar constant adjusted for actual distance from the Sun (average value: 1367 $W/m^2$
$c$ is the speed of light $(3\times 10^8\space m/s)$
$A_s$ is the sunlit surface area in $m^2$
$q$ is the unitless reflectance factor (0 → perfect absorption; 1 → perfect reflection)
$\phi$ is the angle of incidence of the Sun
$cp_s$ and $cm$ are the centers of solar radiation pressure and mass, respectively
“Solar panels are built to absorb as much light as possible in order to generate the maximum amount of power, and reflect only ~2% of the incoming light at near normal angles. As the angle of incidence increases, slightly more light will be reflected, but generally I think you can treat it as a fully absorptive surface. The type of cell used shouldn’t really have an impact”
From SMAD (2005) Table 11-9A
Type: Cyclic torque on Earth-oriented vehicle, constant for solar-oriented vehicle or platform
Influenced Primarily By: