MISR: In-Flight Radiometric Calibration and Characterization Plan

In addition to these modes, the instrument is commanded into a Dark Mode over the darkEarth side of each orbit (excluding Cal-Dark). Here the camera electronics are powered off toconserve energy and there is no data acquisition.2.4 MISSION OPERATIONSMISR operates continuously on the dayside of each orbit. Instrument activities arepreplanned and scheduled. MISR flight computer commands necessary to carry out the missionobjectives are contained in tables covering a 16 day (233 orbit) cycle, which are uplinked on aregular schedule.The instrument commands are loaded by the EOS Operations Center duringEOS-AM/Tracking and Data Relay Satellite System (TDRSS) contact periods. During a nominal24 hour period the instrument cycles between the data acquisition modes and the dark mode oneach orbit. Regular calibrations of the instrument are conducted at specified intervals to maintainthe integrity of performance. Local Mode observations and data acquisitions will change toaccount for seasonal effects or for specific activity monitoring.For each orbit, the beginning orbit boundary is assumed to be the dark side equatorcrossing (ascending node). This enables all data within a swath, including calibrations, to beplanned, commanded, and acquired as a unit.The four science modes (Global, Local, Calibration and Dark) are within the SpacecraftScience Mode and are not individually commanded by the spacecraft. Other operating modes(Standby, Safe, Survival, Test and Off) have a one-to-one relationship to Spacecraft Modes andcan be commanded individually by the spacecraft or ground.2.5 DATA PRODUCTSThe MISR Science Computing Facility (SCF) and Distributed Active Archive Center(DAAC) are the sites where the functions of MISR data product algorithm development andstandard data product generation will be implemented, respectively. The SCF is the site wherequality assessment, algorithm and data product validation, and software development occurs. TheMISR DAAC, which is shared with several other EOS instruments, is the facility at whichsoftware incorporating MISR science algorithms will operate in a high volume, real-time mode toproduce standard science data products.The generation of science data products can be divided into six subsystems within theProduct Generation System (PGS). Each subsystem has at least one primary output product, butmay have other secondary output products. It is convenient to conceptualize the processes withinthese subsystems as occurring in sequence, with the predecessor producing at least one completeproduct, a portion of which is the primary input for the successor. Each of these subsystemscorrespond to a processing level of a product generation flow, as shown in Figure 2.1. These levelsconform generally to the EOS scheme from Level 1 to Level 4. The first two items within theLevel 1B process box (radiance scaling and radiance conditioning) are developed under this planand constitute Level 1B1.In-flight Radiometric Calibration and Characterization Plan, JPL D-1331515