At exactly 9.58 am on Thursday, Indian Space Research Organisation's reliable workhorse PSLV rocket soared into the skies from Sriharikota's first launchpad carrying with it India's first hyperspectral imaging satellite (HySIS), an advanced earth observation satellite, and 30 foreign satellites.

During the 112-minute-long mission, PSLV-C43 will first deliver India's primary satellite into the polar sun-synchronous orbit at an altitude of 630 km and then descend to release 30 international co-passengers at 504 km altitude in two batches. The 30 commercial satellites, including one micro and 29 nano satellites, are from eight countries. Of the total 30 satellites whose combined weight is 261.5 kg, 23 are from the US.

In another first for ISRO, satellites from Australia, Colombia, Malaysia and Spain are being flown for the first time by an Indian rocket.

HySIS weighing 380 kg will be used for a range of applications like agriculture, forestry, soil survey, geology, coastal zones, inland water studies, environmental studies and detection of pollution from industries. Being an earth observation satellite, it will also be used by the military for surveillance purpose.

Though hyperspectral imaging was first tried by ISRO in an 83-kg IMS-1 experimental satellite way back in May 2008 and later on Chandrayaan-1 mission in the same year for mapping lunar mineral resources, this is the first time a full-fledged hyperspectral imaging satellite has been launched.

Hyperspectral or hyspex imaging combines the power of digital imaging and spectroscopy. It collects and processes information from across the electromagnetic spectrum and enables distinct identification of objects, material or processes on the Earth by reading the spectrum for each pixel of a scene from space.

HySIS, which can see in 55 spectral or colour bands from 630 km above the ground, carries two payloads. One to capture images in the visible near-infrared (VNIR) range of the light spectrum and another in the shortwave infrared (SWIR) range. The satellite is designed to provide earth observation service for five years till 2023.

The optical imaging detector array chip in the HySIS satellite has been designed by ISRO’s Ahmedabad-based Space Applications Centre and manufactured by its electronic arm, Semi-Conductor Laboratory, Chandigarh.

Though hyperspectral or hyspex technology in the satellite is still an evolving science and several issues related to it are being sorted out, the technology has become a new trend among space agencies across the world. 

The eight countries whose foreign satellites are being delivered by PSLVC43 are the US (22 nano satellites and one micro satellite), Australia (1), Canada (1), Colombia (1), Finland (1), Malaysia (1), Netherlands (1) and Spain (1). 

PSLVC43 is a four-stage rocket, with alternating liquid and solid stages. This PSLV variant is the lightest version of the PSLV rocket – the core-alone version – that only uses four core stages without six strap-on boosters. Boosters give added thrust to other two PSLV variants. Each stage is built to power the rocket through a different phase in the launch process. 

Today's launch was PSLV's 45th mission overall and 13th of PSLV C43 variant. In the last 25 years, ISRO has launched 52 Indian and 239 foreign satellites from 28 countries, carving a space for itself in the satellite launch market.

This was ISRO's second launch in the month. The space agency had launched its latest communication satellite GSAT-29 on board GSLV MkIII-D2 on November 14.


Our Bureau via TOI