A meteorite has disabled Big Joe, the Johannes Kepler, on a routine run to Mars, killing most of the officers and, on the weaseling out of First Engineer Holtz, putting the burden of command on young Dr. Donald Chase--whose grasp is that of a good science student (and thus not beyond the reach of the reader) although his powers of deduction and leadership emerge as formidable. Crisis is a constant but each has its logical hazardous solution--a record solar storm finds the passengers floating around (inadequate floor space) in the sheathed engine room while Don mans the controls from a washroom filled with life-saving water. The library yields an archaic code for radar-transmission to replace the malfunctioning radio; the recycling water system yields oxygen to supplement lost phylo-plankton--and the meteorite yields an antidote for the unfathomable fever it spreads fast and fatally (as per the adult Plague from Space). Desperation never giving way to despair takes on a tenor of don't-give-up-the-shipmanship but keeping up with Don is tonic enough. More than enough in that the almost-achieved becomes the critically-applied. . . or 'I have seen the future and it functions.'