BENGALURU : After a successful 2023, 2024, too, seems to be an exciting one for the Indian Space Research Organisation (ISRO) as it gears up for its next launch to study black holes and neutron stars on the first day of 2024. The countdown for XPoSat (X-ray Polarimeter Satellite) began on Sunday, December 31, 2023.
XPoSat is India’s first dedicated polarimetry mission to study various dynamics of bright astronomical X-ray sources in extreme conditions. The spacecraft will carry two scientific payloads in a low Earth orbit. “The launch of the XPoSat is set for January 1, 2024, at 09:10 hrs. IST from the first launch-pad, SDSC-SHAR, Sriharikota,” announced ISRO on Sunday. The mission will take flight on the trusted shoulders of the Polar Satellite Launch Vehicle (PSLV). This will be PSLV’s 60th flight.
This mission will make India the second country in the world to launch an advanced astronomy observatory to study these celestial happenings. The first one was by NASA in 2021 called Imaging X-ray Polarimetry Explorer or IXPE.
The completely home-grown satellite lives up to ISRO’s image of launching missions at a minimal cost. According to sources, XPoSat was developed at a cost of Rs 250 crore and is expected to be in space for about five years.
The primary payload POLIX (Polarimeter Instrument in X-rays) developed by Raman Research Institute (RRI) in Bengaluru will measure the polarimetry parameters, degree and angle of polarisation in medium X-ray energy range of 8-30 keV photons of astronomical origin. The XSPECT (X-ray Spectroscopy and Timing) payload made by the Space Astronomy Group of URSC will give spectroscopic information in the energy range of 0.8-15 keV, noted the space agency.
Despite a plethora of information on black holes, the exact nature of the emissions is still unknown. Through XPoSat, scientists can analyse the degree of polarization and the angle of polarization of these emissions from astronomical sources. “The polarimetric observations along with spectroscopic measurements are expected to break the degeneracy of various theoretical models. This would be the major direction of research from XPoSat by the Indian science community,” explained ISRO in a statement.
Another POEM in space
The PSLV Orbital Experimental Module-3 (POEM-3) experiment will be executed meeting the objective of 10 identified payloads, supplied by ISRO and IN-SPACe. Usually, the fourth stage of the PSLV is left to burn in space and create space debris. However, with POEM several experiments will be conducted on space technologies.
After the injection of XPoSat at 650km, the fourth stage (PS4) will be lowered to 350 km, by restarting it twice. The left-out propellant in the PS4 will be disposed of through the main engines as a precursor to enabling the safety of the PS4 stage in atmosphere reentry experiments planned in future. The Oxidiser will be let out first followed by fuel in a predetermined sequence of operations.
The existing scheme of spent stage passivation by venting the tank pressure will also be active. Post passivation of PS4, the control of the stage is transferred to POEM avionics,” ISRO added. The launch can be viewed live on ISRO’s YouTube and Facebook handles from 8:40 am on January 1.
Objectives of the mission