They went down and down and down. A dizzy catwalk took them through the engine room where power was generated for the giant rocket ship, then down again, past passenger compartments into the waist hold, where the fantastic struggle against atomic degeneration was going on. The microphone in Failles' helmet distorted his speech. "I don't think we can hold out much longer," he said. "The walls are so hot they're buckling and beginning to split." "I don't understand all this," Norman said. "What's going on exactly?" "Free radiation got into the fuel tanks," Failles explained. "You know that, of course. It started a chain reaction in the liquified fuel. The stuff degenerates slowly until it reaches a critical stage, then goes all at once. About a billionth of a second. Worse than that, it spreads through the rest of the metal parts. They begin to break down slowly, releasing energy in the form of heat or light, sometimes both. The light radiation kills, the heat corrupts the metal until it gives way, melting or crumbling depending upon its nature. Unless it hits a certain isotope first. In which case, blooey." The scene was an inferno. Dark figures stumbled back and forth in the murk, armored men clumsily struggling with hoses and hand-pumping apparatus. The atomic-powered pumps had long since failed due to wild radiation. The threatened bulkhead was a mighty backdrop of pinkish coppery metal. An eery radiance played over the surface of the laminated plates. The men worked like maniacs deluging the walls and floor with liquified Rayburn's Isotope (a stabilizer) to damp out the degeneration, but already the plates were so hot that the stabilizer vaporized and was instantly dispersed through the room in sparkling clouds. Even filtered by the Conklin glass of his helmet face-plate, the murky glare of the hold made Norman's eyes ache. "How long do we have?" he asked. The speaker in Failles' helmet rattled with a grunt. "That depends. The degeneration period varies according to the route it takes. There are three, possibly four routes in this case. I don't know which it will take. At the outside, five hours." "We'll need at least three hours to reach Hidalgo," mused Norman. "What good will it do to reach Hidalgo? We're taking an atomic bomb with us. If we land with this ship, it'll go with enough power to wipe Hidalgo out of existence and blow a hole in space to boot." Norman frowned. "I thought of that. We won't try to land the ship. We'll have to abandon her and work our way down with the jet cartridges in our space suits." Failles grimaced inside his helmet. "You can get awfully hungry in a space-suit, even if we can take enough spare tanks of air to hold out." Norman nodded.