Tardigrades: How tough are they? Send them into the vacuum and cosmic radiation of space and most bounce back. Subject them to atmospheric pressure 600 times that at sea level and they pick up right where they left off. Chill them to -328˚ F (-200˚ C) for 20 months: no problem. The tiny invertebrates don’t even age during cryptobiosis, adding months, sometimes years, to their lifespan.