With much fanfare, NASA's lunar probe smashed into the moon this past Friday in an attempt to excavate and study hypothetical traces of lunar water ice. As planned, the probe slung an empty rocket hull into a crater at the moon's south pole. The LCROSS probe itself then followed behind the rocket hull, snapping photos and beaming them back to Earth before smashing into the very same crater. The impact appears to have gone off without a hitch, however the crash left many disappointed since the expected 6.2-mile-high cloud of dust, which was to be analyzed for traces of ice, never materialized.
So far, astronomers using ground-based telescopes and the Hubble Space Telescope in orbit have not reported seeing any ejecta plume, but have cautioned that more time is needed to be sure [SPACE.com].
At a post-impact briefing, many in the press expressed concern about the mission's success. In response,
LCROSS project scientist Anthony Colaprete outlined several reasons why the impacts may not have thrown up plumes immediately visible after the impacts, including the [impact] hitting the inner walls of the crater at an angle that ejected the impact pit dust sideways instead of straight up. "Luck plays a part in this," he said, adding. "We have the data we need to address the questions we have and that's the bottom line" [USA Today].
The researchers also say it's possible that the rocket hull hit bedrock instead of loose, gravelly soil as expected, and therefore kicked up only a small debris cloud that wasn't visible to LCROSS. The LCROSS images were supposed to be publicly available via an internet live-feed, but that also did not materialize. However, researchers note that they do have plenty of scientific data to work with: A second spacecraft, the Lunar Reconnaissance Orbiter (LRO), was able to snap thermal image photos of the impact. LRO's thermal scanning device detected a large area of heating near the impact, which scientists are saying
is significant because it can help NASA researchers determine how much water may have been present around the impact sites. While there's still no concrete evidence that vast, exploitable ice reserves exist on the lunar south pole, the LRO photos should provide some idea of how much water might be present near the surface where the LCROSS impacts occurred [Popular Science].
Scientists are also saying that the presence of heat would have cooked any dust that was ejected from the crater, revealing its chemical make-up to the LCROSS probe. That spectroscopic data will take several weeks to analyze--so stay tuned.
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