Some discussion was going on in science circles about what had happened. Speculation centered on the possible success of other types of prober rockets, but it was universally agreed that the time had not come when a manned rocket could safely undertake the difficult trip to Venus and return. The years of space flight since the orbiting of Sputnik I back in 1957 had produced many fascinating results, but they had also brought a realization of the many problems that surrounded the use of rockets for space flight. It was generally believed that no one should risk a manned flight until absolutely everything possible that could be learned by robot and radio-controlled missiles had been learned. It now looked as if Venus and Mars trips were still a dozen years away. Burl Denning was keenly interested in all of this. As a senior in high school, the newly expanding frontiers of the universe represented something special to his generation. It would be men of his own age who would eventually man those first full-scale expeditions to neighbor worlds. By the time he was out of college, with an engineering degree, he might himself hope to be among those adventurers of space. Burl was torn between two interests. Archaeology was both a profession and a hobby in the Denning family. His grandfather had been among the first to explore the jungle ruins of Indochina. His father, although a businessman and industrial engineer, made annual vacation pilgrimages to the ruins of the old Indian civilizations of the Americas. Burl had been with him once before, when they had trekked through the chicle forests of Guatemala in search of a lost Mayan city. And now they were again on a quest, this time for the long-forgotten treasure of the Incas. Burl was thoroughly familiar with the techniques of tracking down the ancient records of mankind. He got along well with natives and primitive people; he knew the arts of wilderness survival; he knew the delicate techniques of sifting sand and dirt to turn up those priceless bits of pottery and chipped stone that could supply pages of the forgotten epics of human history. However, later in the day it seemed as if their particular camp had petered out. There were ruins there--a broken-down wall, a dry well and a bit of eroded bas-relief lying on its side. Burl's father looked at him thoughtfully. The tall, sandy-haired youth was sitting astraddle a pile of dust, methodically sifting it through a wide-mesh strainer. A large pile of sifted sand gave evidence of the length of his efforts, and one broken bit of clay was the only result he had obtained. Two of the Indian guides sat patiently in the shade, watching them. One was digging slowly, turning up more dirt to be sifted.