For 13 years, NASA’s Cassini spacecraft sent back captivating observations of Saturn, and its rings and moons, solving some mysteries but raising plenty of new questions. With the spacecraft’s demise on Friday, the stream of data from Saturn has dried up.

“Until we go back, that’s a very distant world now,” Linda Spilker, the project scientist for Cassini, said during a news conference on Friday. “The details of the rings, and those small moons snuggled in so close — those are all gone until we go back.”

NASA currently has no plans to return to Saturn, but that could change. In the latest round in a scientific competition called specified categories of missions it would consider. Those include a probe to study Saturn’s atmosphere or a mission to go to Titan or Enceladus, two moons known to have oceans.

The New Frontiers program solicits ideas for missions from teams of scientists and engineers. These projects can be ambitious, costing up to about $1 billion. Earlier proposals included Juno, now orbiting Jupiter, and Osiris-Rex, currently en route to the asteroid Bennu.