"I'm looking forward to them detecting at least some level of water ice at the poles. "If the ice is just in the form of very small ice blocks, so to speak, in the lunar regolith, then the radar would not sense that at all," he says. But Campbell believes the moon might harbor small pockets of ice. Radar observations have not turned up telltale signs of water ice, as they have on Mercury and Jupiter's moon Europa, among other places. More recent studies, including an Indian impactor probe last fall, have not yet settled the matter.ĭonald Campbell, an astronomy professor at Cornell University, said scientists have all but ruled out large sheets of ice hidden in shadowed lunar craters. The Lunar Prospector probe later found lunar hydrogen, but no one knows whether it represents water ice deposited by a meteoroid, or if it's embedded in a compound like methane. In the mid-1990s, the Clementine mission found evidence of lunar water ice, but later tests cast doubt on the discoveries. "We're the first mission to go in there and touch the regolith that is bearing this hydrogen compound, and lift it into sunlight to see it," says Anthony Colaprete of the NASA Ames Research Center at Moffett Field, Calif., the principal investigator for the $79-million mission. Scientists know there is hydrogen at the lunar poles-they just don't know if it is locked in water or something else. The Lunar Crater Observation and Sensing Satellite (LCROSS), set to launch June 17 with the better-known Lunar Reconnaissance Orbiter (LRO), could help answer the decade-old question of whether there is frozen water on the moon. That's why NASA plans to crash some trash into the moon this fall. Type A and B orbits were alternated on each revolution, resulting in a seamless, global digital image of the Moon (Figure 20).If humans are to live on the moon someday, or simply use it as a way station for the journey to Mars, water will be a critical resource-and having a local supply would be invaluable. In a type B orbit, mapping began at 90° S and finished at 70° N. In a type A orbit the spacecraft (travelling from south to north) began mapping at 70° S and finished imaging when it was above the North Pole. The images used here were taken with the 750 nm filter as they are close to the visible part of the spectrum and are of better quality than the 415 nm images.īecause of the redundant overlap in surface coverage at high latitudes between consecutive orbits, the Clementine team devised a mapping strategy that conserved data volume. This camera contained five filters and imaged over 99% of the lunar surface at an average resolution of 200 m/pixel. The UV-VIS camera was essentially a digital camera with a 384 × 288 pixel array. The imaging data set shown in this atlas comes from Clementine's ultraviolet-visual (UV–VIS) instrument. This ensured that the entire surface of the Moon was mapped at approximately the same resolution. Because of the elliptical nature of the orbit, perilune (the point of closest approach the lunar surface) was moved from 28° S to 30° N approximately half-way through the mapping phase of the mission (Figure 20). It remained in this 5 h period orbit for 71 days, systematically mapping the surface of the Moon with its instrument suite (Table 4). The Clementine spacecraft entered a 400–3000 km elliptical lunar orbit on 19 February 1994.
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