Could using the gravity of another celestial body allow for something like a bi-elliptic transfer
that uses less delta-v than the theoretical "infinite apogee" delta-v requirement?
If yes, has such a transfer ever actually been performed?
Could using the gravity of another celestial body allow for something like a bi-elliptic transfer
that uses less delta-v than the theoretical "infinite apogee" delta-v requirement?
If yes, has such a transfer ever actually been performed?
Do you mean like this? In that case, a geosynchronous satellite stranded in a 51° inclination orbit used a very high apogee transfer with two lunar flybys at the high apogee to remove 40° of that inclination.