Orbital Mechanics
a = -GM * r_hat / r² -- real inverse-square gravity, symplectic integration.
v_circular = sqrt(GM/r0) = 150.0
v_escape = sqrt(2GM/r0) = 212.1
speed = 150.0 r = 200.0
epsilon = 0.00
parabolic (near escape threshold)
a = -GM * r_hat / r² -- real inverse-square gravity, symplectic integration.