At first, astronauts thought ice was clogging things up, but that theory didn't pan out. Now they think a chemical reaction in the wastewater might be creating debris that blocks the system.
NASA plans to dig deeper once Orion returns to Earth.
Meanwhile, astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen of the Canadian Space Agency are set for a historic splashdown near San Diego on April 10, the first trip this far from Earth since 1972!