Project Title:

Measurement of Solar Radiation Variations as an Influence on Climate

92-1-08.04-8442                                                   NAS05-32409
Measurement of Solar Radiation Variations as an
     Influence on Climate
Applied Research Corporation
8201 Corporate Drive, Suite 1120
Landover, MD  20785
Andrew Endal                                         (301-459-8442)

Abstract:

     The solar disk sextant (SDS) is a spaceborne instrument for
precise measurement of the apparent solar diameter. These
measurements, with simultaneous measurements of the solar
irradiance, will calibrate the historical record of solar diameter
measurements to determine whether changes in the total solar
radiation at the top of the atmosphere have contributed to climate
change. A critical component of the SDS instrument is the beam-
splitting wedge (BSW) that provides the reference angle for
measurement of the solar diameter. This project will develop and
evaluate several BSW designs to determine which can be used in a
long-duration space environment. Specifically, this project will
evaluate molecular bonding of the BSW optical components to
provide a stable wedge angle; a double-wedge design to correct for
chromatic aberration; fabrication processes for the wedge filter;
interferometric methods for pre-flight calibration of the wedge
angle; and on-orbit wedge calibration procedures using the orbital
variations in the Sun-to-SDS distance. The SDS has been selected
as a joint NASA/Italian Space Agency experiment to complement
other NASA climate programs such as the precipitation and
radiation measurements to be provided by the Tropical Rainfall
Measurement Mission.

Potential Commercial Application:

Potential Commercial Applications:  The effort will expand the
firm's capabilities for providing specialized space hardware
subsystems. The potential for penetrating the European market is
particularly important in terms of U.S. participation in this
rapidly expanding area.

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