This paper presents the development of a hyperspectral microwave sensing radiometer, HyMS, for enhanced weather forecasting and climate data records. This airborne instrument employs hundreds of contiguous detection channels, spread across a wide instantaneous bandwidth, 4 GHz. HyMS samples atmospheric molecular absorption features associated with O 2 centered at 54.3 GHz and 66.6 GHz and H 2 O vapour centered at 183.311 GHz. The radiometer was built in a small form factor suited for deployment on a small satellite constellation with the potential to provide high spatio-temporal coverage of the planet. Results from an airborne demonstrator campaign in December 2022 is presented.