 What is the “space cafard” that Si describes?
What's more important—Man's conquest of space, or one spaceman's life? There on the long, long haul to the Jupiter satellites, fearfully checking the symptoms of space cafard, the madness compounded of claustrophobia, monotony, boredom and free fall. He was drafted into the working force reserves, served his time, and is now free from toil for the balance of his life. If it is admitted that our organization has degenerated to the point that we haven't a single pilot, then it might well be that the Economic Planning Board, and especially those cloddies on Appropriations, will terminate the whole Department of Space Exploration."
 It’s the isolation that spacemen feel working alone in space, with only computers as company
 It’s the isolation that spacemen feel working alone in space, with only computers as company  It’s the public’s adverse opinion of space exploration that Gubelin tries to hide.  It’s the desire to return home from a long voyage.  It is the current system of operations for spacecraft, where people man ships with only one person.