Faced with so many imponderables, a well-managed aerospace engineering project would have called a halt to all further work and devoted several years to analyzing the problem down to its minutest detail, exposing pieces of ice to the blast of hypersonic wind tunnels, building simulations, and war-gaming possible alternative strategies. But by the time Markus understood the general shape of the problem, they had twenty-four hours remaining to perigee. The tangerine Earth had grown to the size of an orange. No power wielded by humans could prevent Ymir from passing around it and scraping the atmosphere. They couldn’t even ditch. New Caird, detached from Ymir, didn’t have enough propellant in her tanks to materially change her course and would end up going on the same ride anyway. So Markus made a reasonable guess as to what would be a good angle of attack—the orientation that Ymir would adopt vis-à-vis the atmosphere—and initiated a program of thruster firings that, over the course of half a day, swung the ponderous shard around into the position he deemed best.