ISRO has officially opened its XPoSat (X-ray Polarimeter Satellite) observatory to Indian scientists and researchers, marking a key step in broadening access to India’s latest space-based astronomy infrastructure.

The announcement comes with the release of the first Announcement of Opportunity (AO) cycle, inviting proposals for observational studies using XPoSat’s instruments.

Launched on January 1, 2024, aboard the PSLV-C58 rocket from Sriharikota, XPoSat represents India’s first dedicated mission in X-ray polarimetry — a field that studies the polarisation of X-rays from astronomical sources such as neutron stars, black holes, and pulsars. The satellite operates in a 650-kilometre near-equatorial orbit, providing stable observational conditions for extended research durations.

XPoSat carries two scientific payloads, one of which — XSPECT (X-ray Spectroscopy and Timing) — forms the focus of this AO cycle. XSPECT records spectroscopic and timing data across the 0.8–15 keV energy range, allowing scientists to examine the physical and temporal behaviours of high-energy cosmic sources. ISRO has allocated 60% of the observatory’s operational time between January and December 2026 exclusively for Indian researchers.

According to ISRO’s Science Programme Office, this opportunity will enable the Indian astronomy community to undertake frontline astrophysical research using indigenous, world-class technology. Eligible applicants include Indian scientists and researchers affiliated with institutions, universities, and colleges engaged in astronomy research across the country. All principal investigators (PIs) must demonstrate technical competence in handling and analysing the satellite’s scientific data to qualify.

Proposal submissions are to be made through the XPoSat Proposal Processing System (XPPS) hosted on the Indian Space Science Data Centre (ISSDC) website. The deadline for submissions is November 30, 2025. All submitted proposals will undergo scientific and technical review by the XPoSat Time Allocation Committee (XTAC), which will assess their merit and feasibility.

Once a proposal is approved, the principal investigator will be granted a six-month proprietary data period, allowing exclusive use of the collected data before it becomes publicly accessible through the ISSDC’s data archive. This open-access approach aims to promote transparency and collaborative research within the wider scientific community.

To assist researchers, ISRO has released detailed technical materials such as the XSPECT User Handbook and data planning utilities, including XPoViewer, which helps users calculate satellite visibility windows for their selected targets. These tools ensure that scientists can effectively plan observations and optimise use of the available observation time.

ISRO emphasises that findings derived from XPoSat observations should be published in peer-reviewed scientific journals, with proper acknowledgment of XPoSat data usage. By opening this observatory to national researchers, ISRO aims to strengthen India’s position in space-based astrophysical sciences and cultivate a new generation of space researchers capable of contributing to global high-energy astrophysics.

Based On TOI Report