It seemed like a long time before their father came back. He walked in so fast that his magnetic shoes sounded like tiny hammers. “Kids,” he said, “the captain wants to see you.” “_Us?_” Steve asked. “That’s right. Come quickly.” They went out, leaving some sticks in mid-air and others drifting off. The young Shannons walked shyly into the captain’s room where all the officers stood. Steve felt out of place among the neatly uniformed spacemen. Mr. Shannon was in charge of cargo which the freighter dropped off at different ports in space, for he was an official of the American Space Supply Company. But he had nothing to do with the running of the ship. “Young folks,” said the tall captain, who had a blond mustache, “we want you to help us solve a problem.” “Sir?” Steve asked, puzzled. “Here it is,” went on the chief, in his booming voice. “If we go on past Earth to Sierra to help the _Pole Star_, it’ll leave us with only a fifty-fifty chance of having enough fuel to reach Earth. But the _Pole Star_ is running short of supplies and their radio just went dead a while ago. It’s too late to get help from Earth. The crew is divided on what we should do, so I decided to call you two in to see what you think.” A husky crewman spoke out boldly, “What do these kids know about space, Captain? They’re not even old enough to be out here! I say stick to our course and get this crew and ship back safely to Earth!” The remark angered Steve, but the spaceman looked too big to talk back to. Sue wasn’t so timid. “You ought to be ashamed of yourself!” she exclaimed. “Thinking of yourself when other people are in trouble!” Steve and his father were surprised at Sue’s outburst. Captain Furman and the other crewmen smiled. “I think that solves our problem,” the captain spoke firmly. “If the young lady has courage enough to overlook the risk, the rest of us should have it, too. Thank you, Sue. We move at full rocket thrust to aid the _Pole Star_.” As the Shannons went out into the corridor, Steve asked his sister, “Wow, Sue, what made you talk back to that big fellow like that?” “He was so selfish!” Sue answered. “Besides, it made me mad to hear him say we didn’t know anything about space! Why, we’ve been over almost all of the Solar System, haven’t we, Dad?” Her father pressed her shoulder. “Of course, honey. I’m proud of you, because I felt the same way.” It took a few days for the freighter to reach the asteroid. The space ship, in going past the Earth, had come close enough for the Earth to be seen as a misty, green light. It made the twins long for home as they saw it. “Sierra is like a big meteor, isn’t it, Dad?” Steve asked, as the three of them looked downward on the flat, egg-shaped rock. His father nodded. “It’s often called, ‘The Flying Mountain,’ because of the low peaks on it. Sierra is only a mile long and less than that wide.” “I remember from school that it wasn’t discovered until 1965,” Sue said.