(CNN) - Two U.S. spacecraft are set to crash on the moon Friday. On purpose. And we're all invited to watch.
[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/TECH/space/10/08/probe.moon.crash/art.lcross.nasa.jpg caption="An artist's rendering shows the LCROSS spacecraft, left, separating from its Centaur rocket."]
NASA's Lunar Crater Observation and Sensing Satellite is scheduled to drop its Centaur upper-stage rocket on the lunar surface at 7:31 a.m. ET.
NASA hopes the impact will kick up enough dust to help the LCROSS probe find the presence of water in the moon's soil. Four minutes later, the LCROSS will follow through the debris plume, collecting and relaying data back to Earth before crashing into the Cabeus crater near the moon's south pole.
The LCROSS is carrying 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 will watch, and photograph, the collisions. And hundreds of telescopes on Earth also will be focused on the two plumes.
NASA is encouraging amateur astronomers to join the watch party.
"We expect the debris plumes to be visible through midsized backyard telescopes - 10 inches and larger," said Brian Day at NASA's Ames Research Center at Moffett Field, California. Day is an amateur astronomer who is leading education and public outreach for the LCROSS mission.
Ames will host "Impact Night," an event with music and food starting Thursday evening before a live transmission of the lunar impact will be shown around 4:30 a.m. PT Friday. Other science observatories and amateur astronomy clubs across the country will be hosting similar events. iReport: Are you planning to watch?