LCROSS looks back at Earth
Wed Aug 5, 2009 at 09:00 UTC
On Saturday, Aug. 1, 2009, the LCROSS spacecraft successfully completed its first Earth-look calibration of its science payload. An additional Earth-look and a moon-look are scheduled for the remainder of the cruise phase of the mission.
The purpose of the LCROSS Earth-look was to perform a routine health check on the science instruments, refine camera exposure settings, check instrument pointing alignment, and check radiometric and wavelength calibrations.
From its vantage point of 223,700 miles (360,000 km) from Earth, the LCROSS science team changing exposure and integration settings on the spacecraft's infrared cameras and spectrometers and performed a crossing pattern, pushing the smaller fields of view of the spectrometers across the Earth’s disk. At this range, the Earth was approximately 2.2 degrees in diameter.
"The Earth-look was very successful," said Tony Colaprete, LCROSS project scientist. "The instruments are all healthy and the science teams was able to collect additional data that will help refine our calibrations of the instruments."
During the Earth observations, the spacecraft's spectrometers were able to detect the signatures of the Earth's water, ozone, methane, oxygen, carbon dioxide and possibly vegetation.
Shown is a single spectrum from the down-ward looking Ultraviolet/Visible Spectrometer. Credit: NASA Ames
Shown above are images of the Earth from a distance of approximately 360,00 km. At this range the Earth’s diameter is approximately 2.2 degrees. Top row: Images from the Near Infrared Cameras (NIR1 and NIR2). Bottom Row: Images from the Mid-Infrared (thermal) Cameras (MIR1 and MIR2. The graphic at the right shows the Earth as it was viewed during the activity with the NIR1 spectrometer ‘s Field of View indicated by the inner green circle. Credit: NASA Ames
| Source: NASA Ames Research Center | |
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