For the Cloud Ark, of course, there were plans to cover various contingencies. In the easy case where the atmosphere didn’t expand that much and the drag wasn’t too bad, they didn’t have to do much. In the more difficult case—which was apparently the way the experiment was now shaping up—they had no choice other than to raise the orbit of every vessel they had—Izzy herself, and each arklet. The delta vees involved were not that large; three hundred meters per second sufficed to nearly double the orbital altitude and get them well clear of the danger zone. Each arklet had its own engine and enough of a propellant supply to accomplish that. For Izzy, matters were a little more complicated. If they were willing to ditch Amalthea they could get three hundred meters per second pretty easily. Bringing Amalthea along for the ride, however, increased the propellant requirements enormously. All of which had long ago been anticipated by mission planners. This was how the Dump and Run strategy had been dreamed up in the first place.