Hyperspectral camera delivers high-quality data from space

One year after boarding the Aalto-1 nanosatellite — a 3 kg, CubeSat-based satellite created by students of Aalto University — a hyperspectral camera from the VTT Technical Research Centre of Finland is still going strong in its mission to observe and image the Earth.

The camera operates in a wavelength range of 500–900 nm and is half a CubeSat unit (0.5U) in size, or 5 x 10 x 10 cm. It is unusual for hyperspectral imagers to reach such a small size, as well as to prove capable of surviving in harsh space conditions onboard a small satellite. It has even survived a grade X solar storm while still continuing to supply high-quality data.

“The severe solar storm in fall 2017 was the ultimate test for the ability of our hyperspectral camera technology to withstand extreme space conditions,” said Senior Scientist Antti Näsilä.

While the camera is up in space, it has been possible to program the operation wavelengths from Earth, which makes it easy to scale the same camera hardware to enable different applications. For example, the below spectral image, taken over central Africa in August, shows the Tshuapa River near Mbandaka. The ‘red edge’ of vegetation is clearly visible: the reflectance of the forest rapidly increases around 700 nm.

“It is much more difficult to distinguish these features from the regular camera image of the same target,” said Näsilä. “Hyperspectral imaging can help distinguish information which is not visible from regular images.”

Spectral image taken over central Africa shows the Tshuapa River near Mbandaka. In the image 750 nm is visualised by red pixels, 670 nm by green pixels and 565 nm by blue pixels. Image credit: VTT.

Regular camera image of the same target taken at the same moment as the spectral image. Features of the rainforest are much more difficult to distinguish due to the scattered light from the atmosphere. Image credit: VTT.

Since small satellites are cost-efficient to launch, it is possible to form constellations of multiple SmallSat instruments, which can provide global observation data with better real-time coverage than traditional satellites. This makes it possible to use space technology in the creation of novel service concepts on Earth based on data and AI, expanding to completely new markets such as insurance and agriculture.

VTT’s next instrument waiting to be launched to space is the world’s first CubeSat near- and short-wave infrared (NIR/SWIR) hyperspectral imager. According to Research Team Leader Anna Rissanen, “Data obtained from this new spectral range increases the application potential significantly, because the infrared range beyond the visible wavelengths contains much more information about the chemistry and composition of measurement targets.

“This type of data is useful, for example, in creating novel service concepts for agriculture or in analysing composition of asteroids.”

VTT’s hyperspectral imaging technologies have been developed for a wide variety of wavelengths as well as applications. Rissanen said, “We are constantly looking for partners both from industry and academia in order to create societal impact.”