&quot;Orbital time near the surface doesn’t depend on the size of the object. If two planets or moons, or even asteroids, have density similar to earth, it will take about 90 minutes to get around in low orbit. Size doesn’t matter! (Only density and distance from the surface.)&quot;<p>Density doesn&#x27;t matter either (at least for objects with a mass that is a negligible fraction of the Earth&#x27;s, and even if that is not the case it would be mass that is the primary factor).