Getting up, he clambered over the mail sacks and headed toward the rear of the ship, hunting for the auxiliary fuel-tanks.
Working rapidly, he lugged one out and strapped it into an empty gun turret, making sure he could get it loose again when he'd need it.
He wiped away sweat and checked the angle at which the fuel-tank would face the ground when he came down for a landing. Satisfied, he knocked a hole in the side of the fuel-tank.
"Okay, Ganymede," he radioed. "I'm coming down."
He blasted loose from the tight orbit and rocked the ship down on manual. The forbidding surface of Ganymede grew closer and closer. Now he could see the iceworms plainly.
Hideous, thick creatures, lying coiled in masses around the Dome. Preston checked his spacesuit, making sure it was sealed. The instruments told him he was a bare ten miles above Ganymede now. One more swing around the poles would do it.
He peered out as the Dome came below and once again snapped on the radio.
"I'm going to come down and burn a path through those worms of yours. Watch me carefully, and jump to it when you see me land. I want that airlock open, or else."
"But—"