Apollo-lendude alguseks oli teadlastel kolm peamist hüpoteesi. Haaramis- ehk abikaasahüpoteesi järgi haaras Maa enda ümber tiirlema juba „valmis“ Kuu, mis lendas temast liiga lähedalt mööda.
The discovery of retrograde satellites gave credibility to the capture hypothesis in which the Moon was formed independently, elsewhere in the solar system, and at some time in the remote past it came close enough to Earth to be captured by it.
