The most thrilling moon shot in decades concludes explosvely a little after 5:30 Friday morning.
A Centaur rocket stage will wallop the moon, and if we are fortunate, amateur astronomers will see the plume of dust it kicks up. While this is happening, the Lunar CRater Observation and Sensing Spacecraft will photograph the pummeling from nearby, sending back a stream of pictures as the stage nears and then hits the moon. LCROSS will take images as it follows the Centaur to the surface, with the photos ending only when it hits.
[Still from “Le Voyage dans la lune” (“The Trip to the Moon”), a 1902 film by Georges Melies, placed on the Internet by the Museum of Modern Art, New York City]
On June 18, LCROSS and the Lunar Reconnaissance Orbiter launched from Cape Canaveral Air Force Station, Fla., aboard an Atlas V-Centaur rocket combination. Since then the LRO has gone into orbit around the moon, snapping fascinating views of the terrain, including Apollo landing sites. LCROSS and the upper stage have been swinging by Earth in preparation for the big smash.
The purpose of the impact is to search for ice in a permanently-shadowed crater, Cabeus. The theory is that icy comets have hit the moon for billions of years, and if water vapor splashed into dark craters, it should still be frozen there. When the plume erupts into space above the orb’s south pole, spectrograph readings may show that water is present.
Kurt Fisher, a member of the Salt Lake Astronomical Society who has been instrumental in calculating such factors as plume size and brightness, and posting them on an Internet site dedicated to the experiment, says LCROSS is important from a scientific standpoint. Remote sensing by India’s Chandrayaan-1 moon orbiter indicated the presence of water.
LCROSS will test the “ground truth” that the moon hs water at its poles, he said.
“LRO by remote sensing has fine-tuned” the location of a site where water ice my exist, Fisher added. “LCROSS will go in to physically and ‘ground truth’ a sample of lunar rock.”
Fisher said that even if LCROSS doesn’t find water, “it is only the second such test and not the final answer. In Apollo, we brought back surface rocks from six locations. To say we now ‘know everything about the moon’ is like saying we went to a continent the size of Africa, brought back six buckets of dirt, and there is nothing more to explore.”
LCROSS will test a continent-size polar region by digging a hole 1 meter [about a yard] deep by 20 meters in diameter, he added. “That is one small physical test of a vast lunar region.”
Among his many contributions to the LCROSS project, Fisher established an Internet page on weather predictions for those wishing to set up telescopes for the event. It is located HERE.
Patrick Wiggins, NASA and Jet Propulsion Laboratory solar system ambassador to Utah, had a one-word explanation for his excitement about the event: “Fun!”
It’s fun to drop things from great heights, he said. “The idea of crashing things into the moon is just fun … but the exciting thing is finding water.”
Water is a combination of oxygen and hydrogen. Not only could ice provide water for residents of a moon base, but it could supply oxygen to breathe and hydrogen for rocket fuel, he said. “This could spur human exploration,” not only to the moon but beyond.
Wiggins and other enthusiasts will study the moon through powerful telescopes. So far, the weather forecast is a little iffy — Thursday night should be partly cloudy in northern Utah, while Friday is expected to be sunny. That raises the possibility that the sky will be clear at 5:30 a.m.
Wherever in the United States that dawn hasn’t reached by 5:30 a.m. Friday, amateur and professional astronomers will be scoping out the moon. NASA TV, web site HERE will stream views of the impact live; at 9 a.m. it will broadcast a press conference about the experiment.
Clark Planetarium, based at the Gateway, will host a special presentation and lecture about the project on Saturday, Oct.10, starting 3:30 p.m. Mike Murray, the planetarium’s production manager, will give a public lecture about the experiment in the Hansen Dome Theater.
The planetarium will project videos and still photos on the dome, including images taken by LCROSS as it sped toward its date with the moon at 5,000 mph. Also featured is a program developed by Clark Planetarium and NASA to explain the importance of the search for water. Tickets are available at $1 each.
Following the impacts, the LRO craft will remain on the job, taking photos as it buzzes the surface. It will be compiling a detailed lunar map and checking out sites for a moon base.
Considering the adventure and its possible outcome, Wiggins said, “I’m stoked.”