‘HysIS’ imaging will enable distinct identification of objects from space

by G Hari Kumar

A new set of future satellites called hyperspectral imaging satellites is set to add teeth to the way India is gleaned from about 600 km in space.

On November 29, 2018 a PSLV-C43 lifted off at 0957 hrs (IST) from Satish Dhawan Space Centre SHAR, Sriharikota and successfully launched India’s Hyperspectral Imaging Satellite or HysIS using a critical chip the Indian Space Research Organisation (ISRO) has developed, as per an earlier report by The Hindu.

The new chip, technically called an “Optical Imaging Detector Array,” or OIDA would be tested and perfected during the course of HysIS satellite's life.

ISRO has thus entered the domain of operational hyperspectral imaging from earth orbit with a satellite that can see in 55 spectral or colour bands from 630 km above ground, the space agency developed the chip that suited Indian requirements, the report further adds.

ISRO coyly puts it down as another variety in remote sensing, knowledgeable sources have earlier conceded that it can be highly useful in marking out a suspect object or person and separate it from the background. This could aid in detecting trans-border or other stealthy movements.

Hyperspectral or HysIS imaging is said to be an Earth observation (EO) trend that is being experimented globally. Adding a new dimension to plain-vanilla optical imagers, it can be used for a range of activities from monitoring the environment, crops, looking for oil and minerals all the way up to military surveillance — all of which need images that show a high level of differentiation of the object or scene. Hyperspectral spectroscopy combines the power of digital imaging and spectroscopy.

About a decade ago, ISRO added another EO niche with microwave or radar imaging satellites RISAT-1 and 2 that could ‘see’ through clouds and the dark — an important feature useful for the military and security agencies.

‘HysIS’ imaging is said to enable distinct identification of objects, materials or processes on Earth by reading the spectrum for each pixel of a scene from space.

Another official described it as “another important development by ISRO in its quest for better and diverse Earth observation technologies.” After the successful development at its space application centre, India is venturing into the domain of operational hyperspectral imaging from earth orbit.

ISRO first tried it out in an 83-kg IMS-1 experimental satellite in May 2008. The same year, a hyperspectral camera was put on Chandrayaan-1 and used to map lunar mineral resources. Very few space agencies have such a satellite; a German environmental satellite called EnMAP is due to be launched on an Indian booster by end 2018 or early 2019.

The payloads development centre, Space Applications Centre, designed the architecture of the chip which was made at ISRO’s electronics arm, the Semi-Conductor Complex, Chandigarh. The result is a detector array that could read 1000 x 66 pixels.

HysIS has a Geocentric orbital reference plan placed in a Sun-synchronous Orbit (SSO) with an inclination of 97.95 degree and a Swath width of 30 km. The satellite has an orbital period of 97 mins/26 secs with a 133 orbit repeat interval.

According to an EO expert who called it the ‘CATSCAN’ equivalent of Earth from space, ‘HysIS’ technology is still an evolving science. It comes with many challenges and, as such, space agencies were still ironing out its issues after many years.

Hari is a historian, author, thinker, military enthusiast, cyber geek and the science reporter for IDN. Views expressed are of the author and do not necessarily reflect the views of IDN. IDN does not assume any responsibility or liability for the same