LCROSS Impact From Keck

Results from the W. M. Keck observations of the LCROSS impact are far from certain. The equipment worked as planned, given that this was an unusual sort of observation for Keck this was a pleasant result. The NIRSPEC slit, where light enters the instrument, was perfectly positioned across the impact site. Unofficial word is that they believe they observed the plume and that observations were successful. The press release is rather non-commital, probably best at this point, until they can really go through the results and see if they observed useful data.

Infrared image of the LCROSS impact zone at Cabeus, the horizontal line in the image is the NIRSPEC spectrograph slit, perfectly positioned to observe any plume. Image Credit: Diane Wooden (NASA Ames), Mike DiSanti (NASA GSFC), Eliot Young (SwRI), Al Conrad, Jim Lyke and Terry Stickel (WMKO) and the LCROSS Mauna Kea Spectroscopy Team

KAMUELA, HI—On Oct. 9, astronomers at the W. M. Keck Observatory used the Keck II telescope to search for water harbored in the Moon’s permanently shadowed craters.

The observations were made as part of the Observatory’s participation in NASA’s Lunar Crater Observation and Sensing Satellite, or LCROSS, mission. At 1:31 and 1:35 a.m. Hawaii Standard Time, two LCROSS impactors collided with the crater Cabeus on the South Pole of the Moon.

Diane Wooden of the NASA Ames Research Center in Moffett Field, Calif. used Keck II with its Near Infrared Echelle Spectrograph, or NIRSPEC, to analyze the resulting ejecta plume for the chemical signature of water vapor.

It is the first time that astronomers could use features on the Moon’s surface to properly position the Keck II telescope to take spectroscopic observations and images of the lunar surface. NIRSPEC’s upgraded guide camera and improved guiding software, which are part of the Observatory’s program called MAGIQ, or Multi-function Acquisition, Guiding, and Image Quality, monitoring system, made the spectroscopic observations possible and took the images.

Wooden and the other LCROSS astronomers are currently evaluating the spectroscopic data collected at Keck and the other Mauna Kea observatories for the water vapor signature. The team plans to report the results early next week.