q_abs = (A) (1Sin Ø) (S_c ) (a)

A = Surface Area

1Sin Ø = View Factor = View Factor = View Factor

S_c = Solar Constant (1353 W/m²)

a= Absorptivity (0.90)

Eqn. D1 gives the total thermal absorption due to solar radiation of the exposed surface area when the shuttle is in direct line of sight of the sun.