public static bool RaytracePos(Vessel vessel, Vector3d vessel_pos, Vector3d target, out Vector3d dir, out double dist)
        {
            CelestialBody mainbody = vessel.mainBody;
            CelestialBody refbody = mainbody.referenceBody;

            dir = target - vessel_pos;
            dist = dir.magnitude;
            dir /= dist;

            return Raytrace(vessel_pos, dir, dist, mainbody) && Raytrace(target, dir, dist, mainbody);
        }