The main purpose of the mission was to provide data for a better understanding of the Earth's upper atmosphere and the effects of natural and human interactions on the atmosphere. The objectives of the UARS mission were to conduct research in the atmosphere above the tropopause by measuring the global budget of constituent trace gases and their chemical, dynamic and radiative behavior, as well as the coupling between these processes and atmosphere regions.
The UARS had two major components:
The C&DH provided communications, command and control of the spacecraft and instruments, acquisition and storage of science and housekeeping data, and central computation facilities.
The MACS provided attitude determination and control. The MACS subsystem maintained the Earth-oriented three-axis stability of the spacecraft through the use of star trackers, inertial reference unit, three-axis magnetometers, a Fine Sun Sensor assembly, an Earth Sensor Assembly, and a Coarse Sun Sensor assembly, as well as momentum wheels, magnetic torquers, and attitude control thrusters.
Power was maintained by a six-panel solar array and three 50 Ah batteries. The power subsystem also consisted of the MPS, regulators, solar array drive (which had some problems during summer 92), solar array drive electronics, and power transfer assemblies.
The instrument complement for UARS consisted of nine instruments devoted to the primary atmospheric mission plus one announcement-of-opportunity instrument, the Active Cavity Radiometer Irradiance Monitor II (ACRIM II). The nine primary instruments were:
More information about the mission and the other experiments is available at the UARS home page.
Global images and energy spectra of atmospheric X-rays produced by electron precipitation are obtained over the energy range from 6 to 150 keV with the AXIS instrument. It consists of an array of cooled silicon detectors.
The HEPS instrument consists of six silicon detector telescopes and two surface barrier detectors. These detectors measure protons in the energy range from 0.1 to 150 MeV and electrons from 0.03 to 5 MeV.
The MEPS instrument is made of eight divergent plate electrostatic analyzers. They measure particles in the range from 1 eV to 32 keV.
The magnetometer (MAG) is a tri-axial fluxgate magnetometer on a 1 m boom. Each sensor has a dynamic range of ca. 65000 nT with a resolution of 2 nT and has the capability to measure disturbances in the field in the frequency range 5 - 50 Hz.
The data from these instruments are used as input to computational models (Reber, 1990).
Remarks:
Heynderickx, D., and M. Kruglanski, Flight Data Comparisons, Technical Note 5 part 3, TREND-3, ESA Contract No. 10725/94/NL/JG(SC), 1998.
Reber, C. A., The Upper Atmosphere Research Satellite, Trans. Am. Geophys. Union, EOS, Vol. 71, No. 51, 18/12/1990.
Reber, C. A., The Upper Atmosphere Research Satellite (UARS), Geophys. Res. Let. 20, 1215-1218, 1993.
Reber, C. A., C. E. Trevathan, R. J. McNeal, and M. R. Luther, The Upper Atmosphere Research Satellite (UARS) Mission, J. Geophys. Res. 98, 10643-10647, 1993.
Sharber, J. R., R. A. Frahm, J. D. Winningham, J. C. Biard, D. Lummerzheim et al., Observations of the UARS Particle Environment Monitor and Computation of Ionization Rates in the Middle and Upper Atmosphere During a Geomagnetic Storm, Geophys. Res. Let. 20, 1319-1322, 1993.
Sharber, J. R., et al., UARS PEM Contribution to Radiation Belt Modelling, Proceedings of the Radiation Belt Workshop, Brussels 17-20 Oct. 1995, 1996a.
Sharber, J. R., R. Link, R. A. Frahm, J. D. Winningham, D. Lummerzheim et al., Validation of UARS particle environment monitor electron energy deposition, J. Geophys. Res. 101, 9571-9582, 1996.
Winningham, J. D., J. R. Sharber, R. A. Frahm, J. L. Burch, N. Eaker et al., The UARS Particle Environment Monitor, J. Geophys. Res. 98, 10649-10666, 1993.