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I have a proposal for a following propellantless maneuver. It is propellantless in sense that no mass is lost from spacecraft. It is not reactionless as spacecraft interacts with planet through gravity field. Also law of conservation of energy stands and spacecraft needs an energy source.
Lets assume spacecraft is orbiting planet on an elliptic orbit(orbit is in plane z=0). Spacecraft consists of ejectable reaction mass and main spacecraft - both are of same mass.
At some place in the orbit spacecraft ejects the reaction mass perpendicular to original orbital plane. As both are of same mass following observations can be made: