GALILEO INFRARED IMAGING SPECTROMETRY MEASUREMENTS AT THE MOON

Imaging spectrometer observations were made of the surface of the Moon during the December 1990 flyby of the Earth-Moon system by the Galile o spacecraft. This article documents this data set and presents analys es of some of the data. The near infrared mapping spectrometer (NIMS) investigation obtained 17 separate mosaics of the Moon in 408 spectral channels between about 0.7 and 5.2 mum. The instrument was originally designed to operate in orbit about Jupiter and therefore saturates at many spectral channels for most measurement situations at 1 AU. Howev er, sufficient measurements were made of the Moon to verify the proper operation of the instrument and to demonstrate its capabilities. Anal ysis of these data show that the NIMS worked as expected and produced measurements consistent with previous ground-based telescopic studies. These are the first imaging spectrometer measurements of this type fr om space for the Moon, and they illustrate several major points concer ning this type of observation and about the NIMS capabilities specific ally. Of major importance are the difference between framing and scann ing instruments and the effects of the spacecraft and the scan platfor m on the performance of such an experiment. The science return of subs equent NIMS and other investigation measurements will be significantly enhanced by the experience and results gained.