Calibration Subsystem CAS

The Calibration Subsystem (CAS) project is part of the UVNS instrument of Sentinel-5 (Copernicus) mission.
For in-orbit calibration purposes, CAS will provide calibration signals to the instrument spectrometers.

Copernicus mission goal

The mission is to monitor earth climate by measurements of trace gas concentrations and aerosols in the atmosphere.

  • Air quality measurements
  • Stratospheric ozone monitoring
  • Solar radiation measurements
  • Climate monitoring

S5-UVNS covers bandwidths in the Ultra-Violet (UV), Visible (VIS), Near Infrared (NIR) and Short Wave Infrared (SWIR) spectral ranges.

STI's development CAS for the Sentinel-5 (Copernicus) mission

Micos and SpaceTech are responsible for design, development, qualification, verification and delivery of the overall CAS. The work is related to development of optical, mechanical and mechanism sub-systems of CAS during phases B2, C, and D.

SpaceTech CAS calibration wheel1CAS filter wheel - calibration ports open   SpaceTech CAS calibration wheel2CAS filter wheel - calibration ports closed

Key features of the CAS

CAS hardware deliverables include two independent units:

  • CAS US for UV1, SWIR channels
  • CAS VN for UV2VIS, NIR channels

Main part of the CAS is a filter wheel with different positions to calibrate the Sentinel-5 instrument spectrometers:

  • using the sun as reference
  • using a spectral light source (laser) as reference
  • using a white light source as reference
  • using deep space (mirror) as reference
  • using the dark (closed) as reference