The Secret of the Ninth Planet — Donald A. Wollheim

From Pulpville Press. On the day that the theft of the solar system's light begins, Burl Denning is with an archaeological expedition in the Andes. Within hours the U.S. Air Force has ordered the expedition to investigate the strange phenomenon that is causing a dimness and a drop in temperature throughout the world. This is the start of a fantastic adventure that takes Burl on the first circumnavigation of the solar system on the Magellan. Each planet-fall brings unexpected hazards, as the ship draws closer and closer to solving the mystery of the thest.