InVADER will explore deep-sea vents on Earth to prepare future missions to do the same on watery worlds in the solar system like Europa or Enceladus. (Credit: D. Kelley, University of Washington/NSF-OOI/WHOI)

Some of the most intriguing possibilities for finding life outside Earth are on water worlds like Europa or Enceladus — ocean moons orbiting Jupiter and Saturn. However, those worlds are encased in layers of ice, meaning any ocean exploration will take place far beneath the surface.