Si in Space

Publisher's blurb: In this volume, a stranger comes into town offering the Robertsons the chance of a lifetime―to take a ride in a real spaceship and travel into space. Of course, none of the Robertson crew listens to this crazy person except Si, who pays to be a traveler. When John Luke hears about the opportunity, he decides to tag along for the ride. Soon they’re traveling in space, but the captain of the ship goes unconscious. Can they make it back to earth alive?