Norton had travelled only a few metres when he came across an interruption in the smooth, apparently metallic wall. At first, he thought it was some peculiar decoration, for it seemed to serve no useful function. Six radial grooves, or slots, were deeply recessed in the metal, and lying in them were six crossed bars like the spokes of a rimless wheel, with a small hub at the centre. But there was no way in which the wheel could be turned, as it was embedded in the wall. Then he noticed, with growing excitement, that there were deeper recesses at the ends of the spokes, nicely shaped to accept a clutching hand (claw? tentacle?). If one stood so, bracing against the wall, and pulled on the spoke so…

Smooth as silk, the wheel slid out of the wall. To his utter astonishment—for he had been virtually certain that any moving parts would have become vacuum-welded ages ago—Norton found himself holding a spoked wheel. He might have been the captain of some old windjammer standing at the helm of his ship. He was glad that his helmet sunshade did not allow Mercer to read his expression. He was startled, but also angry with himself; perhaps he had already made his first mistake. Were alarms now sounding inside Rama, and had his thoughtless action already triggered some implacable mechanism?

But Endeavour reported no change; its sensors still detected nothing but faint thermal crepitations and his own movements.

“Well, Skipper—are you going to turn it?”

Norton thought once more of his instructions. “Use your own discretion, but proceed with caution.” If he checked every single move with Mission Control, he would never get anywhere.

“What’s your diagnosis, Karl?” he asked Mercer. “It’s obviously a manual control for an airlock—probably an emergency back-up system in case of power failure. I can’t imagine any technology, however advanced, that wouldn’t take such precautions.”

“And it would be fail-safe,” Norton told himself. “It could only be operated if there was no possible danger to the system…”