ISRO’s XPOSAT soars into the skies on New Year; launch successful

This was the 60th launch of the Polar Satellite Launch Vehicle (PSLV), known as ISRO’s warhorse. With the successful launch of the mission, India has become only the second country in the globe after the US to launch an advanced astronomy observatory to study black holes and neutron stars.

Chennai: Ringing in the New Year in style, the Indian Space Research Organisation (ISRO) on Monday successfully launched PSLV-C58 carrying XPOSAT, the country’s first dedicated satellite to study black holes, and nine other payloads, from the Satish Dhawan Space Centre (SDSC) in Sriharikota near here.

This was the 60^th launch for the Polar Satellite Launch Vehicle (PSLV), known as the space agency’s warhorse. With the successful launch, India has become only the second country in the globe after the US to launch an advanced astronomy observatory to study black holes and neutron stars.

NASA defines black hole as an astronomical object with a gravitational pull so strong that nothing, not even light, can escape it.

The 44.4- metre tall rocket launched the satellite weighing 469 kg with two primary payloads -- POLIX (Polarimeter Instrument in X-rays) and XSPECT (X-ray Spectroscopy and Timing) developed by Raman Research Institute, Bengaluru, and the Astronomy Group of U R Rao Satellite Centre – at 9.10 am from SDSC’s first launch pad.

After about 21 minutes, the rocket placed the satellite into a 650 km Low Earth orbit as intended, making the mission successful. 

“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 6-degree inclination," ISRO Chairman S Somanath announced, as he set a target of 12-14 launches this year.

A Rajarajan, Director, SDSC, said the mission is yet another example of ISRO’s service to humanity as the satellite will study the largely unexplored area of black holes.

“XPOSAT will study stars near the black homes and how X-rays are polarised. The two primary payloads will understand the refraction of X-rays and their polarisation. They will study what black homes are capable of and generate data that will be helpful to scientists across the globe,” he added.

Following the injection of the primary satellite, the PS4 stage began by re-starting twice to reduce the orbit into a 350 km circular orbit during which it launched nine additional payloads developed by start-ups, private firms and educational institutions. “The POEM-3 is being scripted,” ISRO said.

The payloads included a Women Engineered Satellite (WESAT) developed by LBS Institute of Technology for Women to compare Solar Irradiance and UV Index BeliefSat0, which is an amateur radio satellite, from K J Somaiya Institute of Technology, Mumbai.

Jayakumar M, Mission Director, said new technologies like demonstration of fuel cell, and demonstration of silicon based high energy cells will also be carried out during the POEM-3 experiment.

The successful launch of the PSLV-XPOSAT comes after a fruitful 2023 during which the ISRO launched Chandrayaan-3, India’s third unmanned lunar mission becoming the first country to land in the south polar region of the moon, and Aditya-L1, a solar mission.

XPoSat (X-ray Polarimeter Satellite) is the first dedicated scientific satellite from ISRO to carry out research in space-based polarisation measurements of X-ray emission from celestial sources. While the satellite configuration is modified from the IMS-2 bus platform, the Configuration of the mainframe systems are derived based on the heritage of IRS satellites.

While POLIX will measure polarisation of X-rays in the energy band 8-30keV emanating from about 50 potential cosmic sources through Thomson Scattering, XSPECT will carry out long term spectral and temporal studies of cosmic X-ray sources in the energy band 0.8-15keV.

The mission will study the distribution of magnetic field, geometric anisotropies, alignment with respect to the line of sight, nature of accelerators in galactic cosmic X-Ray sources by measuring degree of polarization and its angle and confirm that the production of X-Rays is either from the polar cap of the neutron star or outer cap of the pulsar magnetosphere.

The X-Ray polarisation serves as a crucial diagnostic tool for examining the radiation mechanism and geometry of celestial sources.