Countdown for PSLV/XPoSat New Year day mission to commence tomorrow


Chennai, Dec 30 (UNI)- The countdown for the January one launch of PSLV/-C58/XPoSat, X-ray Polarimeter Satellite, along with 10 other payliOpads, will begin at the spaceport of Sriharikota on Sunday. The Indian Space Research Organisation (ISRO) sources on Saturday said the mission will take off from the First Launch Pad at 0910 hrs on Monday.

After a hugely successful and a landmark 2023 that saw Chandrayaan-3 and Sun exploratory missions, ISRO will ring in 2024 with the launch of the PSLV-C58/XPoSat mission on the New Year day.

About 20 minutes after the lift off, the XPoSat will be injected into an Eastward low inclination orbit of 650 kms by the four-stage ISRO’s reliable workhorse PSLV Launch Vehicle. After injection the PS4 stage engine would be restarted twice to reduce the Orbit.

“After injection of XPoSAT in 650 km, 6 deg orbit, the PS4 stage will be lowered to 350 km 350 km circular orbit by restarting PS4 twice to maintain in 3-axis stabilized mode for Orbital Platform experiments to space qualify systems with novel ideas.

The left out propellant in the PS4 will be disposed through the main engines as a precursor to enabling safety of the PS4 stage in atmosphere re-entry experiments in future. The Oxidiser will be let out first followed by fuel in 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 stage is transferred to POEM Avionics. The PSLV Orbital Experimental Module-3 (POEM) experiment will be executed meeting the objective of 10 identified payloads, supplied by ISRO and IN-SPACe.

XPoSat is the first dedicated scientific satellite from ISRO to carry out research in space-based polarisation measurements of X-ray emission from celestial sources. It carries two payloads, namely POLIX (Polarimeter Instrument in X-rays) and XSPECT (X-ray Spectroscopy and Timing).

POLIX has been developed by Raman Research Institute and XSPECT is by Space Astronomy Group of URSC, Bengaluru.

The POLIX payload serves as an X-ray Polarimeter designed for astronomical observations within the energy band of 8-30 keV. The instrument comprises a collimator, a scatterer, and four X-ray proportional counter detectors surrounding the scatterer. The scatterer, constructed from low atomic mass material, induces anisotropic Thomson scattering of incoming polarized X-rays. The collimator plays a crucial role in restricting the field of view to 3 degrees by 3 degrees, ensuring that only one bright source is within the field of view for most observations. POLIX’s primary objective is to observe bright astronomical sources across various categories during the planned 5-year lifetime of the XPoSat mission. Notably, POLIX stands out as the first payload in the medium X-ray energy band specifically dedicated to polarimetry measurements.

XSPECT is an X-ray Spectroscopy and Timing instrument, designed to offer fast timing and excellent spectroscopic resolution in soft X-rays (0.8-15 keV). XSPECT also monitors changes in line flux and profile, offering simultaneous, long-term temporal monitoring of soft X-ray emission. The instrument employs an array of Swept Charge Devices (SCDs) with an effective area exceeding 30 cm² at 6 keV and an impressive energy resolution of less than 200 eV at 6 keV. XSPECT employs passive collimators to reduce background by narrowing its field of view. This payload is anticipated to observe a variety of sources, including X-ray pulsars, black hole binaries, low-magnetic field neutron stars (NS), active galactic nuclei (AGNs), and magnetars.

On the objective of the XPoSat mission, ISRO said the spacecraft is designated for observation from Low Earth Orbit (non-sun synchronous orbit of 650 km altitude, low inclination of 6 degree), carrying two scientific payloads.

With these two payloads, the XPoSat mission is capable of simultaneous studies of temporal, spectral, and polarization features of the bright X-Ray sources. The mission objectives include measurement of X-Ray polarization in the energy band of 8-30 keV emanated from X-Ray sources, long-term spectral and temporal studies of cosmic X-Ray sources in the energy band of 0.8-15 keV.

The mission life is expected to be 5 years.

The payloads onboard XPoSat will observe the X-Ray sources during its transit through the Earth’s shadow, i.e., during the eclipse period.

On POEM, ISRO said the PS4 stage orbital platform consists of Avionics systems to take care of Navigation, Guidance, Control and telecommands and Orbital Platform Attitude Control System to cater to control of the platform to test the 10 payloads.

The 10 payloads developed by start-ups, education institutions and ISRO centres are the Radiation Shielding Experimental Module (RSEM) by TakeMe2Space, Women Engineered Satellite (WESAT) by LBS Institute of Technology for Women, BeliefSa-t0 Amateur radio satellite by K.J. Somaiya Institute of Technology, Green Impulse TrAnsmitter (GITA) by Inspecity Space Labs Private Limited, Launching Expeditions for Aspiring Technologies -Technology Demonstrator (LEAP-TD) by Dhruva Space Private Limited, RUDRA 0.3 HPGP by Bellatrix Aerospace Private Limited, ARKA-200 by Bellatrix Aerospace Private Limited, Dust Experiment (DEX) by PRL, ISRO Fuel cell Power System (FCPS) by VSSC, ISRO and Si-based High Energy cell by VSSC, ISRO.

You might also like
Leave a comment