<title>Optical calibration of the special sensor ultraviolet limb imager (SSULI)</title>

Abstract

The special sensor ultraviolet limb imager (SSULI) is an ultraviolet limb imaging spectrograph under development by the Naval Research Laboratory for the Defense Meteorological Satellite Program (DMSP). The instrument will measure limb intensity profiles of the earth's airglow in the extreme and far ultraviolet (800 to 1700 angstrom) with 12 - 15 angstrom resolution. The SSULI uses a rotating mirror to scan the instrument field-of-view through 17 degrees to view from 750 km to 50 km tangent altitude. SSULI measurements will be used to infer altitude profiles of ion and electron density and neutral density. A total of five SSULI instruments will be flown on the DMSP Block 5D3 satellites the first of which is scheduled for launch in the latter half of the decade. An additional copy will be flown aboard the Space Test Program (STP) ARGOS satellite in late 1995. Every optical component in SSULI was independently measured followed by system level instrument calibrations. The first SSULI instrument is complete and the preliminary calibration results validate the design expectations. Assembly and calibration of the remaining instruments is underway. This paper presents the preliminary calibration results from SSULI #1 and component test results of the wedge and strip anode microchannel plate detector, grating, collimator and scan mirror. In addition, calibration techniques used to determine detector quantum efficiency, counting linearity, resolution, wavelength and absolute calibration are discussed. A brief discussion of the log term calibration plans for the SSULI instruments including periodic calibration checks during storage, in-flight calibrations using stars and ground truth measurements is presented.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.