The tunnel, by necessity, couldn’t be too close to the Boojum entry bay or someone would inevitably spot activity. And we’d had to be extremely careful about cleaning up after ourselves during excavation. The Heaven’s River maintenance ecosystem included scavengers that patrolled the space between the shells, looking for detritus. So we had a significant hike from the tunnel to the elevator assembly. Most of the mechanism was sunk into the outer shell—the inner shell was still only thirty feet away, but a rail system just ahead of us would accelerate a container to mate with the inner shell when going in, or decelerate the container to mate with the outer shell when coming out.