 What is the “space cafard” that Si describes?
What's more important—Man's conquest of space, or one spaceman's life? It was in the way of an antique, being one of the timepieces made generations past in the Alpine area of Eur-Asia. They also had a banquet for him, complete with speeches by such bigwigs of the Department of Space Exploration as Academician Lofting Gubelin and Doctor Hans Girard-Perregaux. In common with recipients of gold watches of a score of generations before him, Si Pond would have preferred something a bit more tangible in the way of reward, such as a few shares of Variable Basic to add to his portfolio. It was better to retire on a limited crediting, on a confoundedly limited crediting, than to take the two or three more trips in hopes of attaining a higher standard. 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. Possibly somebody like Doc Girard-Perregaux might be horrified at the idea of living in a mini-auto-apartment ... not realizing that to a pilot it was roomy beyond belief compared to the conning tower of a space craft. He was never going to subject himself to space cafard again. His explanation was that a phobia against having his eyes touched prohibited either surgery to remould his eyeballs and cure his myopia, or contact lenses. Doctor Girard-Perregaux was convinced Gubelin would have even worn facial hair, had he but a touch more courage. He said, "Nevertheless, both you and I conform with the present generation in finding it far more pleasant to follow one's way of life in the comfort of one's home than to be confronted with the unpleasantness of facing nature's dangers in more adventurous pastimes." Born in our Ultrawelfare State, he was guaranteed his fundamental womb-to-tomb security by being issued that minimum number of Basic shares in our society that allows him an income sufficient to secure the food, clothing, shelter, medical care and education to sustain a low level of subsistence. Automation being what it is, only a fraction of the population is ever called up. His industrial aptitude dossier revealed him a possible candidate for space pilot, and it was you yourself who talked him into taking the training ... pointing out the more pragmatic advantages such as complete retirement after but six trips, added shares of Basic so that he could enjoy a more comfortable life than most and the fame that would accrue to him as one of the very few who still participate in travel to the planets.
 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.