Ref edit
- Kepler orbit: F=G(m1m2/r^2)
- Equations of motion
- Specific orbital energy
- Orbital period
- Orbital_speed: v=2pi(a/T) : v^2=u/a
- Escape velocity: =(2u/r)^0.5
- G = Gravitational constant 6.67e-11 m^3 kg^-1 s^-2
- F = Force
- m, m1, m2: mass
- v = velocity
- u = GM = Standard gravitational parameter
- r = Radius