XPoSat launch: 5 key things about ISRO's bid to unravel black hole mystery

This is the first dedicated scientific satellite from the space agency to carry out research in space-based the polarisation measurements of X-ray emission from celestial sources, according to ISRO

The Indian Space Research Organisation (ISRO) welcomed the New Year on January 1 with the successful launch of PSLV-C58, carrying XPoSat and 10 additional payloads. The PSLV-C58 rocket deployed XPoSat into an eastward low-inclination orbit. The Polar Satellite Launch Vehicle (PSLV) lifted off at 9.10 am from the Satish Dhawan Space Centre in Sriharikota.

Aiming to unravel the mystery behind black holes, PoSat is the first dedicated scientific satellite from India's space agency to carry out detailed research on X-ray emission from celestial sources. It will investigate the polarisation of intense X-ray sources in space.

Prime Minister Narendra Modi extended his best wishes to ISRO and the space fraternity for the launch of the PSLV-C58. In a post on X, the PM wrote “A great start to 2024 thanks to our scientists! This launch is wonderful news for the space sector and will enhance India’s prowess in this field. Best wishes to our scientists at @isro and the entire space fraternity in taking India to unprecedented heights.”

Astrophysicist Dipankar Bhattacharya told NDTV that the endeavour was a “textbook launch”. "The expected orbit has been achieved. Now all the expected science is hopefully going to work as planned," he said.

Here are five key things to know about the X-ray Polarimeter Satellite (XPoSAT).

The XPoSAT mission launch marked the 60th flight of the Polar Satellite Launch Vehicle (PSLV). The 260-tonne rocket carries an advanced astronomy observatory to study black holes and neutron stars. India has now become the second country after the US to have such a specialised “observatory” of this kind to study black holes.

The XPoSat carried two payloads- POLIX (Polarimeter Instrument in X-Rays), which is designed to measure polarimetry parameters by Raman Research Institute, and XSPECT (X-ray Spectroscopy and Timing), built by the U R Rao Satellite Centre, Bengaluru.

Bharat's monumental stride in the space.

Congratulations to our @isro scientists on the historic launch of specialized astronomy observatory satellite XPoSat to study black holes and neutron stars in our galaxy. Brightening up the cosmos in pursuit of knowledge on the very first… pic.twitter.com/jrI3hBpxOX

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— Amit Shah (@AmitShah) January 1, 2024

The satellite will measure the polarisation of X-rays in the energy band 8-30keV emanating from about 50 potential cosmic sources. It will complete long-term spectral and temporal studies of cosmic X-ray sources. X-ray polarisation aids in looking behind the radiation mechanism and geometry of celestial objects.

Also read: Four start-ups to launch experiments on board ISRO's PSLV-C58 flight

Eventually, the ISRO scientists will bring the satellite to a lower altitude of about 350 km by restarting the fourth stage of the vehicle. This will be to conduct the PSLV Orbital Experimental Module-3 (POEM-3) experiment.

ISRO spent Rs 250 crore (approximately $30 million) on the XPoSat satellite. The NASA IXPE, which has been conducting a similar mission since 2021, spent $188 million. XPoSat is expected to last more than five years in comparison to the two-year life span of the NASA IXPE.

Aim of the mission

ISRO said now that the concept of space-based study of X-ray polarisation is gaining importance globally, India’s XPoSat mission will play a crucial role. The XPoSat mission is expected to bring considerable benefits to the global astronomy community.

After the launch, ISO chairperson Somnath said, “On January 1, 2024, yet another successful mission of PSLV has been accomplished. PSLV-C58 has placed the primary satellite - XPoSat - in the intended orbit of 650 km with a 6-degree inclination. The new year has begun with the launch of the PSLV, and we will have an exciting time ahead.”