"I'll make it," he said aloud, with nobody else to listen on all Pluto. "I'll make it!"
Faster he urged the engine's rhythm, and faster. He clocked its speed by the indicators on the housing. A hundred and fifty miles an hour. A hundred and sixty; not enough. Whipping the boom line tight around his waist to hold his course steady, he sighted between the upcurve of the runner forward. There was level, smooth-frozen country, mile upon mile. He speeded up to one hundred and seventy-five miles an hour. More. The sled hummed at every joining.
At noon, he had done a good thousand miles. At mid-afternoon, sixteen hundred. Two and a half hours of visibility left, and more than four hundred miles to go.
"I can do those on my head," muttered Wofforth to himself, and then, far in the distance, the flat rim of the horizon was flat no longer.
It had sprung up jagged, full of points and bulges. Speeding toward it, he steered by the line around his waist while he cut his engine. He came close at fifty miles an hour, almost a crawl.
Some ancient volcanic action had thrown up those mountains, like a rank of close-drawn sentries. The sled could not cross them anywhere. Still reducing speed, Wofforth drew close to a notch, but the notch gave into a crater, a great shallow saucer two miles in diameter and filled with shadows below, so that Wofforth could not gauge its depth. Opposite, another notch—perhaps once the crater had been a lake, with water running in and out. If he had come there at noon, he could have seen the bottom, and perhaps—
"But it isn't noon." Wofforth was talking to himself again. His voice sounded thin and petulant in his own ears. "By noon tomorrow, the heat will be out of this suit."
He stopped the sled, unlashed himself and trudged to the notch. He stood in it, looking down, then across.
The little bright jewel of the sun, sagging toward the horizon, showed him the upper reaches of the crater's interior, pitched at an angle of perhaps fifty degrees.
Even if it had been noon, it would have been no use. The sled could never climb a slope like that.