&gt; As you extend the not inconsiderable mass of the cable towards the earth, your centre of gravity will move inward with it<p>What I&#x27;m saying is that without firing rockets, there&#x27;s nothing you <i>can</i> do to change the trajectory of your centre of mass. When you &quot;extend&quot; the cable towards earth, presumably you are pushing on it in some way, and there will be an equal and opposite reaction. You don&#x27;t have to &quot;carefully move the ship outwards&quot; - the ship (which is inherently &quot;massy&quot;, as it has the rest of the cable as cargo) will move outwards by itself, exactly the right amount for the centre of gravity of the ship-cable system to <i>remain</i> in geostationary.<p>So I still don&#x27;t see what two cables gets you apart from keeping the ship itself exactly at geostationary, which strikes me as unimportant.