Future moon astronauts may find water more accessible than previously thought, according to a new experiment that suggests the sun is replenishing the sought-after resource on the lunar surface.

Because the moon lacks a magnetic field like Earth's, the barren lunar surface is constantly bombarded by energetic particles from the sun; these particles make up the solar wind. Scientists have long suspected, based on computer simulations, that the solar wind helps make the ingredients of water on the lunar surface.