NASA crashes on the moon -- twice

(CNN) -- Two U.S. spacecraft crashed on the moon Friday. On purpose.

NASA's Lunar Crater Observation and Sensing Satellite dropped its Centaur upper-stage rocket on the lunar surface at 7:31 a.m. ET.

NASA hoped the impact would kick up enough dust to help the LCROSS probe find the presence of water in the moon's soil. Four minutes later, the LCROSS followed the probe through the small debris plume, collecting and relaying data back to Earth before crashing into the Cabeus crater near the moon's south pole.

The LCROSS carried spectrometers, near-infrared cameras, a visible camera and a visible radiometer. These instruments will help NASA scientists analyze the plume of dust -- more than 250 metric tons' worth -- for water vapor.

The orbiting Hubble Space Telescope and NASA's Lunar Reconnaissance Orbiter watched, and photographed, the impacts. And hundreds of telescopes on Earth also were focused on the site.