ISRO has formally invited Indian researchers to submit proposals for accessing data from the XPoSat Mission, India’s first dedicated X-ray polarimetry satellite launched on 1 January 2024.

This marks a major opportunity for the country’s astronomical community to study black holes, neutron stars, and active galactic nuclei using unique polarisation measurements.

The Indian Space Research Organisation announced on 22 June 2026 that proposals can only be submitted by scientists or researchers residing and working at Indian institutes, universities, or colleges. This ensures that the mission’s scientific benefits remain within the national research ecosystem, strengthening India’s leadership in space science.

XPoSat currently orbits Earth in a near-equatorial orbit at an altitude of 650 kilometres. It carries two payloads: POLIX (Polarimeter Instrument in X-rays), developed by the Raman Research Institute, which measures the degree and angle of polarisation in the medium X-ray energy range of 8–30 keV, and XSPECT (X-ray Spectroscopy and Timing), developed by ISRO’s Space Astronomy Group, which provides spectroscopic and timing information in the 0.8–15 keV range. Together, these instruments allow simultaneous polarimetric, spectral, and temporal studies of cosmic sources.

The mission is India’s first satellite dedicated to X-ray polarimetry. Polarisation adds two new dimensions to astrophysical research: the degree of polarisation and the angle of polarisation. These parameters serve as diagnostic tools to understand emission processes from extreme cosmic sources. 

Prior to XPoSat, astronomers relied mainly on spectroscopic, imaging, and timing data from ground-based and satellite observatories across optical to radio frequencies. While valuable, these methods left gaps in understanding the precise nature of emissions from celestial objects. XPoSat helps bridge these gaps by breaking degeneracies in theoretical models of emission processes.

The mission has a planned life of five years and is expected to provide long-term datasets. Observations will be scheduled between September 2026 and March 2027, with selected proposals gaining access to proprietary data.

After six months, archived data will be made available through the Indian Space Science Data Centre (ISSDC), ensuring wider access for registered users. This approach balances proprietary research opportunities with eventual open access for the broader scientific community.

XPoSat was launched aboard PSLV-C58 from Sriharikota on 1 January 2024. The mission marked a milestone in India’s space science program, positioning the country among the few nations capable of conducting dedicated polarimetry studies.

By studying how X-ray polarisation works in space, researchers can probe the origins of emissions, energy sources, and even unravel mysteries surrounding supernova explosions and accretion processes in black holes.

This Announcement of Opportunity represents a significant step in maximising the mission’s scientific return. It encourages Indian astronomers to leverage cutting-edge datasets, expand knowledge of high-energy astrophysical phenomena, and contribute to global research while reinforcing India’s sovereign capabilities in space science.

PTI