Solar maximum mission/ultraviolet spectrometer and polarimeter studies

This final report for NASA Contract No. NAS8-35921 describes various studies performed for the Ultraviolet Spectrometer and Polarimeter (UVSP) experiment, one of several instruments on the Solar Maximum Mission (SMM) satellite which was launched on 14 February 1980. The UVSP consisted primarily of a Gregorian telescope and an Ebert-Fastie spectrometer with a polarimeter that could be inserted into the light path. The spacecraft and most of the instruments, including the UVSP, operated successfully until 23 November 1980, when part of the SMM attitude control system (fine pointing control) failed. The UVSP was then unable to observe the Sun until 18 April 1984, when the SMM was visited by the space shuttle and the attitude control module was replaced by astronauts. The SMM mission ended when the spacecraft reentered the atmosphere of the Earth and was thereby destroyed on 2 December 1989. The topics covered in this report include the following: (1) ultraviolet stellar polarimetry (probably the first such attempted measurement); no polarization as detected and the upper limits, based on the sensitivity as determined by the observed count rate, are rather high; (2) an investigation into the possible position of the UVSP wavelength drive after it became stuck on 26 April 1985; (3) fast timing tests for sit-and-state observations involving one or two detectors; (4) development of computer subroutines to allow the calculation of the component of the SMM spacecraft orbital velocity along the line of sight to the Sun at any desired time during the 1984/1985 period when the UVSP wavelength drive was operating properly; (5) listing of published research papers; (6) description of the UVSP catalog of observations; and (7) description of UVSP calibration report and data users guide.