sentences:  Sent out both to gather information and as a show of force to reassure a vengeful Earth population, the force first goes through an extremely grueling training period on Earth and on the planet Cerberus (a fictitious planet beyond Pluto, not the satellite of Pluto which had not been discovered at the time the original novel was written).The exercises involve military and technical training under extreme circumstances and with live weapons, including the use of nuclear weapons and various other advanced armaments.They are designed to make Mandella and his compatriots into the most powerful infantry forces ever, to combat a foe whose physiology is still totally unknown.