The HYPSO project

The hyperspectral payloads of the HYPSO satellites aims to observe ocean color and detect harmful algal blooms (HABs) using a custom-built pushbroom hyperspectral imager (HSI). The satellites will work as a part of a larger system and inform other agents such as drones, ships and underwater vehicles of potential interesting areas in the ocean that should be investigated further. 

The hyperspectral imager will cover the spectral range of 400 to 800 nm, with a spectral bandpass of 3.3 nm, and has a swath width of 70 km. The satellite will perform a slew maneuver during a scan to induce more overlapping frames during data acquisition, which will result in a spatial resolution better than 100 m. The imager’s expected signal-to-noise ratio is characterized for typical open ocean water-leaving radiance which can be flexibly increased by binning pixels. 

The HYPSO-1 mission is described in detail in Grøtte et al. “Ocean Color Hyperspectral Remote Sensing with High Resolution and Low Latency – HYPSO-1 CubeSat Mission”

HYPSO satellite 

he first HYPSO satellite, HYPSO-1, is scheduled for launch in January 2022. It is a 6U CubeSat and will be launched into a 500 km sun-synchronous orbit. The ground station at NTNU will be used for communication and downlinking data, as well as other ground stations such as KSAT Svalbard. 

Since high-dimensional hyperspectral data need to be transmitted over limited space-to-ground communications, we have designed a modular FPGA-based onboard image processing architecture that significantly reduces the data size without losing important spatial-spectral information. 

The HYPSO-1 satellite at NanoAvionics testing facilities in Lithuania.
Figure 1: The HYPSO-1 satellite at NanoAvionics testing facilities in Lithuania. 

Hyperspectral payload 

The hyperspectral payload consists of a hyperspectral imager and an RGB camera. The HSI is a custom-built pushbroom imager with a transmissive grating, designed for the spectral range of 400 to 800 nm. The full spectral range of the instrument is about 220 to 960 nm, but close to no light is recorded below 400 nm and wavelengths above 800 nm are contaminated with second order diffraction effects. The theoretical spectral bandpass is 3.33 nm, and all measured values are below 5 nm. 

Figure 2: HYPSO-1 hyperspectral payload. RGB (top of image) and HSI (bottom of image). The mounting plate is not part of the payload. 

The RGB camera will be used for geo-referencing and geo-spatial validation of the hyperspectral data. More information about the HSI can be found in

Prentice et al. “Design of a Hyperspectral Imager Using COTS Optics for Small Satellite Applications”

and 

Henriksen et al. “Pre-Launch Calibration of the HYPSO-1 Cubesat Hyperspectral Imager”