/// <summary>
 /// Circularize around Moon
 /// - currently only onRails is implemented
 /// </summary>
 private void CircularizeAroundMoon()
 {
     // check ship is on segment where it near Moon
     if (onRails)
     {
         KeplerSequence keplerSeq = spaceship.GetComponent <KeplerSequence>();
         OrbitUniversal orbitU    = keplerSeq.GetCurrentOrbit();
         if (orbitU.centerNbody == moonBody)
         {
             // in orbit around the moon - do circularization
             OrbitData     orbitData       = new OrbitData(orbitU);
             OrbitTransfer circularizeXfer = new CircularizeXfer(orbitData);
             keplerSeq.RemoveFutureSegments();
             keplerSeq.AddManeuvers(circularizeXfer.GetManeuvers());
         }
     }
     else
     {
         // assume we're in orbit around the moon
         OrbitData orbitData = new OrbitData();
         orbitData.SetOrbitForVelocity(spaceship, moonBody);
         OrbitTransfer circularizeXfer = new CircularizeXfer(orbitData);
         ge.AddManeuvers(circularizeXfer.GetManeuvers());
     }
 }