Astronaut's rhymes with:
aquanauts, huguenots, aquanauts, huguenots, aeroflot's, afterthoughts, apricots, aquanauts, boycotts, crackpots, croat's, croats, ersatz, feedlots, gunshots, hot-shots, hotshots, huguenots, jackpots, kilowatts, mascots, megawatts, ocelot's, oviatt's, potshots, robot's, robots, slingshots, snapshots, sunspots
Astronaut's sounds like:
accouterments, accoutrements, astronautic, astronautics, astronauts, astronauts'