A NASA mission that was retired in 2022 has helped scientists detect water on the surface of two asteroids.

Researchers from the Southwest Research Institute were able to use data from the retired Stratospheric Observatory for Infrared Astronomy, a joint project between NASA scientists and the German Space Agency at DLR, to discover the water molecules, according to a news release and scientific paper. Previously, scientists had detected some form of hydrogen in the asteroids but could not distinguish between water and its close chemical relative, hydroxyl.

Scientists studied four asteroids that were rich in silicate, a material that includes silicon and oxygen among other molecules, and found that two of the asteroids had molecular water on two of them. These types of asteroids develop close to the sun, and learning more about this type of asteroid can help show how materials in space were distributed and have evolved.