The Norwegian Space Agency needed help launching a HySpex camera for use on microsatellites.
The original theoretical project between the Norwegian company NEO and the European Space Agency (ESA), examined the concept of hyperspectral imaging for small satellites, (HISS). Several years on and with a good deal of research under their belt, the company is now closing the loop. The CEO of Norsk Elektro Optikk, (NEO) Trond Løke explains that HySpex is now launching into space with two partners, the European Space Agency and the Norwegian Space Agency.
So why is hyperspectral image gathering so important for use in satellites?
Hyperspectral images produce a spectrum of several hundred colours, (represented as numbers) for each pixel in an image. Coloured images captured by a camera can discriminate between, for example a rock, a cow and trees in a landscape. However, hyperspectral images can discriminate between the different types of rocks, cows and trees. This is because hyperspectral imaging, ‘analyses a wide spectrum of light’ instead of just assigning primary colours such as red, green, blue, to each pixel captured. The light striking each pixel is broken down into many different spectral bands providing a great deal more information on what is actually imaged by the camera.
HySpex NEO already has experience capturing imaging data of a wide variety of objects such as gathering data with a camera on a UAV or, installed in an aircraft for tasks such as surveying forests to detect the distribution of different species of trees and their location, to improve forest management. This powerful tool allowed 2Excel Geo to quantify the canopy coverage and even identify specific indicators such as valuable information on ash dieback amongst the trees in the forest.
Working in conjunction with Skycam Aviation in California and EchoLabs from Canada, data was captured on the distinct geological features of the Cuprite Hills in Nevada, USA. In this survey a HySpex VS-620 was mounted on a UAV, with the imaging data synchronised with that being collected by Skycam using a HySpex VNIR-1800 and SWIR-385 mounted in an aircraft. The process secured benchmark imaging data that is now made available to anyone on request to HySpex.
Detecting airborne methane gas was another project undertaken by SkyCam Aviation Inc using a HySpex SWIR-384. On-the-ground methane detection is a long and costly process and while a SWIR hyperspectral camera mounted on a UAV provides a great solution, perhaps a better one will be found with the upcoming HySpex satellite camera currently being tested.
The hyperspectral camera being tested by HySpex for microsatellites surpasses the common limitations inherent with the small satellite platform to allow fast and economical access to space so that a broader range of industries have access to remote sensing data. The company acknowledges that creating a high-performance hyperspectral camera for a small platform is challenging as achieving useful spatial resolution in combination with acceptable signal-to-noise-ration (SNR) is particularly difficult.
Current hyperspectral cameras operate a ground sampling distance (GSD) of less that 30 metres in the short-wave infrared – or SWIR range, of 1,000 to 2,500nm, with rarely less than 10 metres in the visible and near-infrared, VNIR, range of 400 to 1,000nm. To make sure the HySpex camera provides advantages over its competitors, NEO determined the ground sampling distance was especially important. A major goal of the company was to have a high spatial resolution in their new satellite camera, but this caused conflicting design parameters in terms of a narrow swath. However, it is possible to compensate for this by using a ‘constellation’ of microsatellites launched at the same time. A method recently used in India where a constellation a satellites apparently hitched a ride on SpaceX’s Transporter-4.
Testing the new HySpex high-altitude camera saw Trond Løke travel to the NASA Armstrong Flight Research Centre for high-risk, atmospheric flight research and test projects in Edwards, California. Here the camera installation procedure was tested followed by test flights in an ER-2 aircraft. With the assistance of the U.S Geological Survey team a Mjolnir-V1240 – high altitude edition camera, was installed in the nose of an ER-2 aircraft.
“The HySpex stratospheric UAV payload was installed in the nose of the NASA, National Aeronautics and Space Administration’s ER-2 and ready for its first test flight to capture images from 20km altitude,” Løke explains. “We were able to capture hyperspectral images from the stratosphere which we can show in a section of landform. Realising the capability of image capture was very rewarding and exciting.”
Løke said that HySpex NEO was very grateful for the work provided by the team at NASA and members of the U.S Geological Survey team, what they have achieved will contribute to the final development of a HySpex hyperspectral camera for microsatellites. The camera is optimised for a much smaller platform than the ER-2 and will next be flight tested on a Swift HALE stratospheric UAV at NASA.
This new stratospheric instrument is now a commercial product offered by HySpex, NEO. HySpex cameras are already in use in Australia and New Zealand. After several years of working with the group in Norway and undertaking training in camera operations and data interpretive software, Dr. Cédric Chaminade and the team at Raymax Applications can assist in explaining the value of hyperspectral imaging to Australia’s own production of microsatellites.