sleeper ship
Science fiction term for a spacecraft whose crew and/or passengers are in suspended animation during a long voyage.
In that sci-fi novel, they travel to another star system over hundreds of years aboard a sleeper ship.
Compound of 寝台 (shindai, 'bed') + 船 (sen, 'ship'), literally 'bed ship'. The term is a calque from English 'sleeper ship' used in science fiction.