Lieutenant Commander David Ashton thrives on excitement. As he strolls to the White House he has the feeling a new adventure awaits-and he's not disappointed. President Gardiner offers him the mission of a lifetime something he's trained for all of his life.Gardiner explains that the United States is running out of oil. In desperation he is dispatching the Excalibur the largest starship ever built to voyage beyond the solar system to a distant planet 103 light years from earth. For the first tim