About four decades ago, in the 1970s, experts began taking photos of our environment from orbital satellites using multi-spectral remote sensors. These instruments produced pictures that have a small number of braid wavelength bands, but they allowed for experts to gain a deeper insight into everything around us. Then, the idea appeared that a new technology could be produced, which would snap images in a few hundred narrow spectral bands, thus providing even more insight into study targets. But, until only recently, this has remained just an idea, experts at the European Space Agency (ESA) say.
But now, decades later, the idea was transposed into reality. The Earth-observation community is fascinated by the possibilities that the new technology, called hyperspectral imaging, provides. As far as remote-sensing capabilities go, this approach to conducting science is gaining increasingly large amounts of support from many sides, including from space agencies such as NASA and ESA. Hyperspectral imaging is also known as imaging spectroscopy, experts say.
The NASA Jet Propulsion Laboratory (JPL), in Pasadena, California, developed the first instrument of this sort in the 1980s. It was called the Airborne Visible-Infra Red Imaging Spectrometer (AVIRIS), and represented the earliest step for things to come. It was also the first device in its class capable of operating from a moving platform. Today, there are two sensors using this technology in orbit. One is called Hyperion, found on NASA’s Earth Observing-1 satellite, and the other dubbed CHRIS, on ESA’s Proba-1 spacecraft. Neither of them is capable of producing a global map of the planet.
Over the next five years, three missions featuring hyperspectral imaging abilities are scheduled for launch. The medium-resolution hyperspectral imaging mission Prisma will be launched by the Italian space agency ASI and it will acquire images over 235 individual channels, in visible, near-infrared and short-wave infrared wavelengths.
“Prisma is an Earth-observation system with innovative electro-optical instrumentation that combines a hyperspectral sensor with a panchromatic, medium-resolution camera. The advantages of this combination are that, in addition to the capabilities offered by hyperspectral sensors, which can determine the chemical-physical composition of the target, the panchromatic adds a higher spatial resolution and the recognition of the geometrical characteristics of the scene,” says expert Giancarlo Varacalli, the ASI Prisma system manager.