September 12, 2014

Laboratory Breadboard


A laboratory breadboard of IASI for expertise and validation.

To validate the design of the IASI instrument and study its optimisations, CNES has developed a laboratory breadboard that reproduces the main functions of the instrument:

  • flux collection,
  • collimation,
  • interferometry,
  • field of view,
  • pupilla imaging.

It differs however from the instrument on the following points: the spectral range is reduced to [3.3 µm,5µm], only one pixel is available at a time, and the scan period is longer (1 s vs. 151 ms).

Located at the CNES Space Center in Toulouse, the breadboard optical bench is 1.5 m long and 1 m large. It is operated under vacuum, the InSb detector is cooled to 77 K by liquid nitrogen. It includes a hot calibration black body at 23°C and a cold one, also coolded by LN2. The experiments are controlled by a computer that drives the target mirror, reads the housekeeping data and stores the scientific data. All these elements are shown on a drawing. Different infrared sources may be injected into the breadboard. A HeNe laser at 3.39 µm spread all over the field of view and the pupilla, an external black body, or the downwelling atmosphere flux coming from the sky, reflected through an outdoor mirror at 45°. In that case, a video camera shoots views of the clouds within the field of view. The breadboard can be seen on photo # 1.

The IASI breadboard is used for different purposes, in association with the industrial prime contractor, and the scientists of the project.