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doi:10.1038/nindia.2015.131 Published online 28 September 2015

India places astronomy observatory in space

A gift to the world's astro-scientific community, says ISRO

K. S. Jayaraman

The Astrosat is dedicated to the study of celestial objects.


© ISRO
Astronomy research in India is poised for a big boost with yet another text-book launch by the Indian Space Research Orgnaization (ISRO) that put into orbit the Astrosat, a satellite dedicated to the study of celestial objects, today.

Weighing 1,513 kg and estimated to have cost around Rs. 1.8 billion, Astrosat, built by ISRO, was launched by its Polar Satellite Launch Vehicle (PSLV) from the Satish Dhawan Space Centre at Sriharikota in the southeastern coast of India. Televised live, it was PSLV's thirty first -- and the thirtieth consecutive successful flight -- since its debut in 1993.

Twenty-two minutes after lift-off Astrosat entered into a 645 km near equatorial orbit around the Earth from where, ISRO said, it will scan the distant universe for at least five years. ISRO chairman A. S. Kirankumar said it as an "eventful day" for the astronomy and astrophysics community.

Riding piggyback on PSLV are six foreign satellites — one each from Indonesia and Canada and four from the US — together weighing 118 kg. This is the first time since it relaxed its export control rules that the US has allowed its satellites to be launched by ISRO.

Although most of ISRO’s spacecraft launched till now were for specific applications like communication, Earth observation and more recently navigation, it's very first one — Aryabhata — was a science satellite. The third and fourth of the Stretched Rohini Satellite Series launched during early 1990s; Youthsat, a joint Indo-Russian satellite launched in 2011; Chandrayaan-1 to the moon; and the Mars obiter launched last year, all carried science payloads. Astrosat is different in that it is India's first science satellite dedicated to the study of astronomy.

ISRO described Astrosat as "a multi-wavelength observatory" with payloads capable of simultaneously observing the universe in the visible, ultraviolet and X-ray regions of the electromagnetic spectrum. The mission aims to understand high energy processes in neutron stars and black holes, estimate their magnetic fields, detect bright X-ray sources in the sky and perform a limited survey of the universe in the ultraviolet region, ISRO said.

Former ISRO chairman K. Kasturirangan described Astrosat with its ability to scan the universe in multiple wavelengths as "one of its class in the world that can open a new era in astronomical research." Though it took a decade to build and launch, "it is very relevant even today," he said.

To perform its tasks, Astrosat carries five different payloads on board developed by ISRO and its partner institutes — Tata Institute of Fundamental Research in Mumbai; Indian Institute of Astrophysics and Raman Research Institute in Bengaluru; and the Inter-University Centre for Astronomy and Astrophysics in Pune. Two payloads — Ultraviolet Imaging Telescope and Soft X-ray Telescope — involved partnership with Canadian Space Agency and the University of Leicester (UK) respectively.

The science data telemetered to ISRO's ground station in Bengaluru will be processed, and distributed to astronomers in participating institutions in India for analysis. Data from all the payloads will be available in about two months, according to M. Annadurai, director of ISRO Satellite Centre in Bangalore which built the Astrosat.

According to ISRO the foreign passengers — Indonesia's LAPAN-A2 microsatellite (76kg) and Canada's NLS-14 nanosatellite (14kg) are meant for providing maritime surveillance. The four American LEMUR nanosatellites each weighing 7kg "are non-visual remote sensing satellites, focusing primarily on global maritime intelligence through vessel tracking via the Automatic Identification System, and high fidelity weather forecasting using GPS Radio Occultation technology."