In addition, output products are generated and distributed based on requests in a queue independent of the above chain. Outside the processing chains are tasks like making images for presentations and the JPL Public Information Office . This performance evaluation stage is mainly a subset of normal processing, but must be performed on the first and last science runs on a tape before normal processing can commence. Sometimes problems result in short throwaway runs or missing runs. These must be noticed so that the proper site names can be matched with the good data.
Normal processing begins with downloading and decommutating the data, known as the download process.
Thus, the first processing reads the data from the tape, pads it with leading zeroes for storage in 16-bit integers, and writes it to magnetic disk. This stored data is extracted at will with the Performance Evaulation Programs, or PEPs, which also plot the data to model instrument behavior graphically. Then they are processed to reduce them to 307x1536 strips with no header or separating data. If the investigator wishes raw data, then PG only copies the data from archive tape to the desired distribution medium. However, most of the time the investigator wishes radiometrically corrected data.