"I can give that to you without calculating," said Timkins. "Telfu is similar to Terra within twenty percent. Terra's attenuation amounts to twenty-nine percent; in other words, the attenuation due to the presence of Terra in the light-line between source and measuring device is twenty-nine percent greater than it would be if Terra were not there and the spacial attenuation only cut the strength." "Thirty percent, roughly, because it's easier to figure," said McBride. He made calculations, set them down linearly as to the magnitudes, and then transferred the vectors to the curve. "That's one large bit closer," he said. "We'll better that, some day. But for now, playmates, I've had my Idea-for-the-Week. Let's cut us another caper around Telfu at right angles to this curve. One side will pass the peak and the opposite side will cut the cusp. Same distance, same speed, same everything. Follow?" "At some distance." "I believe that we will find a place where the cusp really comes down closer to Telfu," said McBride. "How much drive inefficiency can we tolerate and still lift?" "From Telfu? Not enough to keep the breakers from blowing. And don't say wire 'em shut. They're right on the ragged edge now, on account of we know what we're doing and do not want to blow circuit breakers during experiments unless they are really in trouble. But the gravitron-cupralum driving equipment is not our only ace in the bucket. The emergency batteries, though inefficient, can still put us down and get us off. Providing, of course, that your map there gives us a chance." "Not knowing the orbital constants of Soaky; the plane of Soaky's ecliptic: the rotational features of Telfu, we are taking chances. One rotation of Telfu might be plenty safe if we hit it on the nose. Two might put us out here and then we'd have to go through seven years of astronomical investigations before we found the place where that cusp came in again--and we'd probably have to wait anything from sixteen to nine thousand years before Soaky passed overhead again. The latter might get boring. But we can take a chance on one day, plus whatever angular movement Soaky makes with Telfu as center." "Think Soaky's ecliptic is fairly close to Telfu's equator?" "Within twenty or thirty degrees. I'm assuming the old theory of the Planitesimal Hypothesis. Sling out your molten stuff, let it condense, and you'll find everything rotating in the same direction in about the same plane. Might be clockwise or counter-clockwise, but only one way per solar system. One moon in all of the junk that goes around Sol is contrariwise--and they think that was a captured wanderer. The greatest obliquity is somewhere near forty degrees, most of the large planets being less than ten, I think."