“Space regulations,” answered Biff. “If a meteor should hit one of us, the other ship would explode too if we were close. Also, rocket tubes are so tricky that you never know when one is going to misfire and send your ship scooting off suddenly in the wrong direction.” One end of a double cable was fastened to rings on the freighter’s platform. Then the other end was tossed across the space between the two ships and attached by the scientists to their own side. Steve saw the crewmen around him pick up cords from out of the cable equipment box. They fastened one end to buckles on their suits and the other to the cable. Steve guessed that the lines were a safety measure to keep the men from drifting off into space as they carried the cargo across. The first crewman picked up a crate as lightly as if it were a pile of feathers. Then with his foot he shoved off from the platform. He guided the crate through the emptiness with his gloved hands and the men on the opposite platform helped him aboard. Another crewman stepped off the freighter with another crate. Then another crewman with another piece of cargo. The carriers returned by the other cable line. Steve went over to his dad who, as an official of the American Space Supply Company, was supervising the work as always. “Dad, may Sue and I carry a box across? We’ll be careful.” Mr. Shannon thought a moment. “I suppose it will be all right. There’s no way you can go adrift if you fasten on to the cable. But you have to be careful you’re snapped on securely.” Mr. Shannon made a place for them in line. Sue in front. There was a wait before Sue’s turn so that more crates could be placed on the platform’s edge. The children looked beyond Apollo’s Chariot at the huge black circle of Mercury as it masked the mighty sun. “Biff,” Steve asked his friend as he was stacking the crates, “why couldn’t the Apollo scientists study the sun from Mercury?” Biff chuckled and it made a funny crackling sound over the young Shannons’ radios. “Men will land on Mercury when they grow hides of asbestos, Steve. It’s so hot on the sunward side that there are supposed to be lakes and pools of lead there! The other side never sees the sun, so you can imagine how cold it is! Think you two would like to go there?” “I should say not!” Sue answered for both of them. When the next piece of cargo was ready to go over, Biff checked the children’s safety cords. Then he let Sue push off from the platform with a box in front of her. A few moments later, Steve followed. The boy heard his sister giggle excitedly as they floated across. Searchlight beams were in their eyes but they didn’t mind. Steve, too, thought this great fun after being cramped for so long on the freighter. He looked down at the empty space below, but he knew he could not fall and so was not afraid. Reaching the other platform, he and his sister were helped aboard.