Data Set Overview: The Lunar Prospector merged telemetry data set is a result ofcomparing the two Lunar Prospector telemetry data streams andselecting one of them. The Lunar Prospector raw telemetry datadownlink stream contains data transmitted in real-time and data thatwas collected about 50 minutes prior and stored on the spacecraft.The purpose of the delayed stream is to capture data acquired duringcommunications blackouts. See the CONFIDENCE_LEVEL_NOTE field for adescription of the merging process. The merged telemetry data set contains raw science and instrumentengineering data acquired by all of the science instruments (GammaRay, Neutron, and Alpha Particle Spectrometers, and the Magnetometerand Electron Reflectometer), along with spacecraft engineering data.As such, the merged telemetry files are part of the Lunar ProspectorLevel 0 data archive. The data set is organized into binary fileswith each file containing about 4-6 hours of data. Each record in agiven file is a main (minor) frame containing 2 seconds of downlinkeddata. A major frame consists of 16 minor frames. Science Objectives: The Lunar Prospector science objectives relevant to this data set areto map the Moon's surface composition and its magnetic field, and todetermine the frequency and location of gas release events. A specialemphasis of the science objectives is to search for polar water icedeposits [BINDERETAL1998].

Confidence Level Overview: The merging process compares each minor frame of the real-time anddelayed data streams. When mismatches occur between the two datastreams, the data stream with the highest signal-to-noise ratio ischosen for storage in the merged file. When there are no mismatches,the real-time data stream is chosen. When mismatches occurs betweenthe two streams, and the signal-to-noise ratios are the same, thereal-time stream is selected. Where there is only one data stream fora given time, that stream is stored in the merged file. Each minorframe (i.e., each record in a merged telemetry file) has a flag toindicate which stream was selected and which criteria was used for theselection. Data Coverage and Quality: Science data are acquired continuously by the Lunar Prospector scienceinstruments. Over time, the entire lunar surface is covered from thecircular polar orbit of the spacecraft. However, data gaps can occurin the merged telemetry data files. The times of these data gaps aredocumented in a log file included with the level 0 archive.