Objectives
SHIMMER, the primary payload of STPSat-1 from March 2007 through October 2009, had four main objectives:

  1. Fly in space, for the first time, a monolithic Spatial Heterodyne Spectrometer (SHS) to increase the technical readiness level for this innovative optical technique
  2. Observe mesospheric OH (hydroxyl) on a global scale at all (daytime) local times to investigate atmosphere photochemistry
  3. Observe Polar Mesospheric Clouds (PMCs) at the edge of their polar occurrence region
  4. Validate NOGAPS-ALPHA/ NAVGEM saturation modeling

Approach

  • SHIMMER uses the first monolithic Spatial Heterodyne Spectroscopy (SHS) interferometer, which allowed the design of a high resolution UV spectrometer that was a factor of 7 smaller and lighter than a comparable, conventional grating spectrometer
  • OH density profiles were derived from OH resonance fluorescence signal superimposed on the bright “blue sky” scattered background
  • PMC occurrences and brightnesses were inferred from enhanced scattered UV at PMC altitudes
  • STPSat-1 was operated for 1 year by the DoD Space Test program and for an additional 1.5 years by NRL from Blossom Point MD
  • SHIMMER data is being used to advance understanding and near-predictive capability of the space domain, towards exploiting the geospace environment and its impact on Navy/ Marine Corps systems

Deliverable/Value/Accomplishment

  • Successful demonstration of SHS technique on orbit
  • First global mesospheric OH data set covering all daytime local times
  • Multi year PMC data set at the edge of the PMC regions
  • OH data solved long standing HOx dilemma (a fundamental question about the atmospheric HOx photochemistry)
  • PMC data allowed validation of high altitude extension of Navy operational weather prediction system
  • SHS is now a new, demonstrated space sensing tool