Space payload

Optics & mechanics

• A microwave telescope to beam and point the microwave signal toward ground-based observatories in Chile and Europe. A mechanism is needed to point specific observatories. Our baseline at the moment is to move the primary mirror.  

• The polarizing grid sets the orientation of the polarization signal. Like for the COSMOCal prototype, its orientation is measured illuminating the grid with a visible laser. The diffraction pattern recorded on a CCD camera determines the polarization angle. 

• A CCD imager is used to record the diffraction pattern of the polarizer on a visible CCD. A flip mirror changes the optical path so that the CCD can be used with a visible telescope to image the Earth. By combining the two images, we can determine the polarization angle of COSMOCal relative to Earth coordinates with the required accuracy.

Microwave source

The microwave source with three frequency channels at 90, 150 and 270 GHz, and an option (goal) for a fourth channel at 860 GHz. The source concept follows from that of the Submillimetre-Wave Instrument (SWI) microwave spectrometer of JUpiter ICy moons Explorer (JUICE), a large-class mission of ESA's Cosmic Vision (Treuttel et al. 2023).