LUNAR PROSPECTOR MISSION DELIBERATELY CRASHED INTO MOON

After the final Apollo moon landing in 1972, no American spacecraft was to touch Earth’s nearest neighbour for more than a quarter century. Then came Lunar Prospector, a small satellite built to circle the moon and map its surface composition. Launched in 1998, its key discovery was the detection of hydrogen near the lunar poles. The hydrogen was thought to be evidence of lunar ice hidden in places out of reach of direct sunlight. To test the idea, scientists chose to end the mission in spectacular fashion: The spacecraft was sent crashing into a permanently shadowed crater near the lunar South Pole. Scientists hoped to raise a cloud of debris that could be spotted by telescopes on Earth and analyzed for water vapour. The probe crashed on target, but no debris cloud was seen. However, in striking the moon’s surface, Lunar Prospector achieved another goal. It was carrying some of the ashes of planetary scientist Eugene Shoemaker, who was involved in training the Apollo astronauts. He had been a candidate to fly himself but was disqualified for health reasons. With the end of Lunar Prospector, his wish to reach the moon was finally realized.