In the meantime, though, during these few minutes when they were just inching along, they could work magic. Small changes in velocity out here led to enormous transformations in their orbit down there. Endurance, by dint of enduring for three years and persevering in her plan, had reached Cleft’s distance from Earth. But she’d always been in the wrong plane: the same plane that Izzy had started out in, the plane that had been chosen, seemingly a million years ago, because it was easily reached from the Baikonur Cosmodrome. Down there, deep in the gravity well, changing that plane would have been catastrophically expensive. If they’d had an Earth to go back to, it would have been cheaper to start from scratch and build a new space station than to move Izzy to the plane where the moon had once orbited. Up here, though, by burning the engines at apogee, they could nudge it closer and closer to the desired plane at much lower cost. So they’d been doing little plane change maneuvers at each apogee. It had been going on for months now. It was a thing that had to happen if they were ever to reach Cleft, but it made Doob’s stomach burn, made him wish he hadn’t had a couple of slugs of hoarded single-malt.