It may have been as effective as a nuke, in terms of how much damage the thing inflicted. The formula for the amount of kinetic energy released by something hitting something else is: E = .5 * m * v*v As you can see, the velocity is a really big influence on the amount of energy produced, since it's squared. A 1 lb weight hitting the ground at 2 miles per hour generates 4x as much kinetic energy as that 1 lb weight hitting the ground at 1 mile per hour. Given there's no atmosphere on the moon, the spacecraft would have hit the moon at 25,000 miles per hour (rough guess). No atmosphere means no drag and no terminal velocity. it was certainly accelerating when it hit the ground, due to the moon's gravitational pull. http://spaceflightnow.com/atlas/av020/090610lcross.html LCROSS weighed 5,216 pounds. It hit the moon at 1.6 miles/second (5760 miles/hour). The Centaur impact will excavate greater than 350 metric tons of lunar material and create a crater 66 feet (20 m) in diameter to a depth of 13 feet (4 m).
