I just don't get what I'm missing. Since the elements of the object are not connected, they drop out of the problem related to starting and stopping at a doorway. Since no acceleration is specified, it is unlimited. Since a door can be represented by a single drone, the question simply dissolves to "How fast can one drone - with no explicit limit on its acceleration - take to travel one light hour?" And the answer is: a time that approaches zero (given acceleration without bound). There must still be some condition, obvious to you, going unstated. Otherwise, where does my solution go wrong?