By the time Feldman could settle into the sacklike hammock, the _Navaho_ began to shake faintly, and weight piled up. It was mild compared to that on the shuttle, since the big ships couldn't take high acceleration. Space had been conquered for more than a century, but the ships were still flimsy tubs that took months to reach Mars, using immense amounts of fuel. Only the valuable plant hormones from Mars made commerce possible at the ridiculously high freight rate. Three hours later he began to find out why spacemen didn't seem to fear dying or turning pariah. The tube quarters had grown insufferably hot during the long blast, but the main tube-room was blistering as Ben led the men into it. The chief handed out spacesuits and motioned for Dan. "Greenhorn, aincha? Okay, I'll take you with me. We go out in the tubes and pull the lining. I pry up the stuff, you carry it back here and stack it." They sealed off the tube-room, pumped out the air, and went into the steaming, mildly radioactive tubes, just big enough for a man on hands and knees. Beyond the tube mouth was empty space, waiting for the man who slipped. Ben began ripping out the eroded blocks with a special tool. Feldman carried them back and stacked them along with others. A plasma furnace melted them down into new blocks. The work grew progressively worse as the distance to the tube-room increased. The tube mouth yawned closer and closer. There were no handholds there--only the friction of a man's body in the tube. Life settled into a dull routine of labor, sleep, and the brief relief of the crude white mule from the still. They were six weeks out and almost finished with the tube cleaning when Number Two tube blew. Bits of the remaining radioactive fuel must have collected slowly until they reached blow-point. Feldman in Number One would have gone sailing out into space, but Ben reacted at once. As the ship leaped slightly, Feldman brought up sharply against the chief's braced body. For a second their fate hung in the balance. Then it was over, and Ben shoved him back, grinning faintly. He jerked his thumb and touched helmets briefly. "There they go, Dan." The two men who had been working in Number Two were charred lumps, drifting out into space. No further comment was made on it, except that they'd have to work harder from now on, since they were shorthanded. That rest period Feldman came down with a mild attack of space-stomach--which meant no more drinking for him--and was off work for a day. Then the pace picked up. The tubes were cleared and they began laying the new lining for the landing blasts. There was no time for thought after that. Mars' orbital station lay close when the work was finished. Ben slapped Feldman on the back. "Ya ain't bad for a greenie, Dan. We all get six-day passes on Mars. Hit the sack now so you won't waste time sleeping then. We'll hear it when the ship berths."