Lunar Prospector will Crash into the Moon!

Spacecraft ar e very expensive things, costing millions of dollars. When one blows up or is destroyed, it's normally a devastating thing. Investigative committees are formed to determine what went wrong and the most minute piece of evidence is checked and rechecked. On July 31, the spacecraft Lunar Prospector will crash into the moon, but rather than devastating, this will be a much anticipated and planned for event!

Lunar Prospector was launched on Jan. 6, 1998, with a one-year primary and six-month extended mission to explore the lunar surface remotely. Prospector is the first NASA mission to the moon in 25 years. It is is part of NASA's Discovery program , a program which employs low cost spacecraft to explore the solar system. The spacecraft itself is a small spin-stabilized  craft, meaning it rotates around its own central axis to control its orientation.

In March 1998, mission scientists announced that Lunar Prospector 's instruments had  detected sufficiently large quantities of hydrogen at the lunar poles. This implied the presence of water ice. Later that same year in September scientists estimated that up to six billion metric tons of water ice may be buried in the permanently shadowed craters of the Moon's poles. The presence of water ice on the moon would be extremely important for a lunar base and the hydrogen could be a source of fuel for spacecraft.

Now, as Prospector nears the end of its useful life, NASA plans to do one final test which may show us the evidence of water ice. Prospector will be directed to crash into a permanently shadowed crater near the Moon's south pole. The spacecraft weighs 354 pounds but the impact will be the equivalent of crashing a two-ton car at more than 1,100 miles per hour! Such an impact should "splash" a good deal of material up from the crater floor.  It is hoped that such ejecta might be visible from space and ground based observatories. If so, it could provide definitive proof of the water ice.

The crater was carefully chosen for the impact. It is about 35 miles in diameter and has a high enough  rim that the crater is in constant shadow, but the rim is low enough to allow for suitable spacecraft impact trajectory. Previously collected data suggests that this crater is a likely candidate to have water ice. Another factor was this crater is easily observable at impact time from both orbital and earth-based observatories.

Scientists have cautioned though that if the impact doesn't show water ice, that does not mean there is none there. It is highly possible that the spacecraft will impact into a part of the crater in which there is no water ice. It is also possible the impact will not be sufficient enough to eject up enough material to be observed. Still, everyone is hopeful.

The Hubble Space Telescope and many observatories here on Earth will be watching the impact in the early hours of July 31. The rest of us will have to wait for pictures and results from those places since the impact is much too small to be seen with the naked eye or a small telescope.