“If we had such an advanced design,” said Redell, “and I just don’t believe it possible—would we gamble on a remote-control system? No such system is perfect. Suppose it went wrong. At that speed, over fifteen thousand miles an hour, your precious missile or strato ship could be halfway around the globe in about forty-five minutes. That is, if the fuel held out. Before you could regain control, you might lose it in the sea. Or it might come down behind the Iron Curtain. Even if it were I smashed to bits, it would tip off the Soviets. They might claim it was a guided-missile attack. Almost anything could hap pen.” “It could have a time bomb in it,” I suggested. “if it got off course or out of control, it would blow itself up.” Redell emphatically shook his head. “I’ve heard that idea before, but it won’t hold up. What if your ship’s controls went haywire and the thing blew up over a crowded city? Imagine the panic, even if no actual damage was done. No, sir—nobody in his right mind is going to let a huge ship like that go barging around unpiloted. It would be criminal negligence. “If the White Sands calculations were correct, then this particular saucer was no earth-made device. Perhaps in coming years, we could produce such a ship, with atomic power to drive it. But not now.” Redell went over several other cases. “Take the Godman Field saucer. At one time, it was seen at places one hundred and seventy-five miles apart, as you know. Even to have been seen at all from both places, it would. have to have been huge—much larger than two hundred and fifty feet in diameter. The human eye wouldn’t resolve an object that size, at such a distance and height.” It was an odd thing; I had, gone over the Mantell case a dozen times. I knew the object was huge. But I had never tried to figure out the object’s exact size. “How big do you think it was?” I asked quickly. This could be the key I had tried to find. “I haven’t worked it out,” said Redell. “But I can give you a rough idea. The human eye can’t resolve any object that subtends less than three minutes of arc. For instance, a plane with a hundred-foot wing span would only be a speck twenty miles away, if you saw it at all.” “But this thing was seen clearly eighty-seven miles away—or even more, if it wasn’t midway between the two cities. Why, it would have to be a thousand feet in diameter.” “Even larger.” Redell was silent a moment. “What was the word Mantell used—‘tremendous’?” I tried to visualize the thing, but my mind balked. One thing was certain now. It was utterly impossible that any nation on earth could have built such an enormous airborne machine. just to think of the force required to hold it in the sky was enough to stagger any engineer. We were years away—perhaps centuries—from any such possibility. As if he had read my thoughts, Redell said soberly, “There’s no other possible answer. It was a huge space ship—perhaps the largest ever to come into our atmosphere.”