Press Release

Subaru Participates in Observations of Momentous Lunar Impacts

October 9, 2009

Computer screens during observation

Does water ice exist on the Moon? The answer to this longstanding scientific question is the main goal of NASA's mission with LCROSS (Lunar Crater Observing and Sensing Satellite), which was launched together with the LRO (Lunar Reconnaissance Orbiter) by an Atlas rocket on June 18, 2009. The culmination of the mission occurred on October 9, 2009, when the 2nd stage of the Atlas rocket crashed into Cabeus crater (98 km in diameter) near the south pole of the Moon at 1:31am HST, followed a few minutes later, at 1:35am HST, by LCROSS’s impact into the Moon's surface, exactly according to NASA's plans. The LRO spacecraft, the Hubble Space Telescope, and ground-based observatories were ready to observe the impacts and analyze the resulting plume of chemicals, dust, and debris to determine whether water ice does exist on the Moon. Subaru Telescope was among four other observatories (Keck, Gemini, NASA's IRTF, Caltech Submillimeter Observatory) on the summit of Mauna Kea that took part in observations of this momentous event.

Artist's illustration (NASA)

The Subaru team of astronomers, from the University of Tokyo, the Japan Aerospace Exploration Agency, and the National Astronomical Observatory of Japan, used the near-infrared camera and spectrograph (IRCS) mounted on the Subaru Telescope to make spectroscopic observations that could detect water in the ejecta. A quick data analysis of their data for about two hours after the impacts took place indicated that the team needs more detailed data analysis to confirm how successful their observations of the ejecta were. If the Subaru data detect water, the scientists will estimate the total amount of water inside the Cabeus crater.

Confirmation of water on the moon will help to provide a foundation for future lunar exploration and scientific research.

In Subaru observation room



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