Small satellites are i.a. characterized by providing fast and economical access to space, making remote sensing data available for a broader range of communities. Due to their small size, several micro-satellites can be launched at the same time, and constellations of microsatellites are feasible due to their low cost. The temporal resolution and ground coverage achievable through a constellation of small satellites cannot be matched by a single, large, satellite.
The Ground Sampling Distance (GSD) of existing and planned satellite Hyperspectral Imagers (HSIs) is rarely less than 30 meters in the SWIR range (1000 to 2500 nm) and rarely less than 10 meters in the VNIR range (400 to 1000 nm). NEO concluded that the GSD appears as a weak point limiting the usefulness of existing, institutional, instruments. The conclusion was made after interviewing existing HySpex customers, and what NEO regards being the participant sentiment at the PRISMA workshop (April 2021). Additionally, these huge instruments require equally large satellite platforms, which again drives the cost significantly.
With co-funding from the Norwegian Space Agency in 2020 and 2021, NEO made a preliminary design for a SWIR HySpex hyperspectral imager suitable for a microsatellite.
Having high spatial resolution as a major goal for HySpex’ HSI satellite design, unavoidably leads to an instrument with a narrow swath. These conflicting design parameters may determine the usefulness of the instrument for different applications. NEO focused on the GSD spec, since an unsatisfactory swath width can be compensated by using a satellite constellation, whereas GSD, once designed, cannot be changed. Also, existing HySpex customers have explicitly stated that they would prefer having a smaller GSD over a wider swath.
Creating a high-performance, small platform compatible, HSI is challenging. Achieving useful spatial resolution in combination with acceptable signal-to-noise-ratio (SNR) is particularly difficult. One of the goals of the development was to devise an HSI that surpasses the common limitations introduced by small satellite platforms and, in some respects, provides hyperspectral data that are better than what is currently available for free from larger instruments.
NEO is currently working on funding the qualification of the instrument.