Two-maneuver indirect contingency return from a low lunar orbit

The problem of contingency return from the low lunar orbit is studied.A novel twomaneuver indirect return strategy is proposed.By effectively using the Earth’s gravity to change the orbital plane of the transfer orbit,the second maneuver in the well-known three-maneuver return strategy can be removed,so the total delta-v is reduced.Compared with the singlemaneuver direct return,our strategy has the advantage in that the re-entry epoch for the minimum delta-v cost can be advanced in time,with a minimum delta-v value similar to that of the direct return.The most obvious difference between our strategy and the traditional single-or multiplemaneuver strategies is that the complete transfer orbit is a patch between a two-body conic orbit and a three-body orbit instead of two conic orbits.Our strategy can serve as a useful option for contingency return from a low lunar orbit,especially when the delta-v constraint is stringent for a direct return and the contingency epoch is far away from the return window.