ISRO begins countdown for launch of PSLV-C58/XPoSat, to study black holes, neutron stars

World over, there are going to be celebratory countdowns to ring in the New Year 2024. The Indian space agency ISRO has also commenced a countdown ahead of New Year's Eve that will go well into New Year's day.

However, this is not a countdown for revellers, but ISRO's PSLV-C58/XPoSat rocket launch that has been scheduled for 9:10 am, IST, Monday (Jan 1), 2024.

The countdown starts in the year 2023 at 8:10 am, Sunday, (Dec 31) and the rocket's launch will take place in 2024 at 9:10 am Monday, (Jan 1), 2024.

From the first launchpad of Satish Dhawan Space Centre(SDSC), the 44-m tall rocket would be lifting off, carrying India's XPoSat (X-ray Polarimeter Satellite), the country's first dedicated polarimetry mission to study various dynamics of bright astronomical X-ray sources in extreme conditions.

The XPoSat spacecraft comprises two scientific payloads that will be placed in a low earth orbit. The primary payload POLIX (Polarimeter Instrument in X-rays) will measure the polarimetry parameters (degree and angle of polarization) in a medium X-ray energy range of 8-30 keV photons of astronomical origin. The XSPECT (X-ray Spectroscopy and Timing) payload will give spectroscopic information in the energy range of 0.8-15 keV.

#isro explainer video on #xposat 👇
"Emissions from celestial objects- blackholes, neutron stars, other energetic events arise from intricate events & are challenging to understand. To surmount this, ISRO is launching India's 1st polarimetry & spectroscopy satellite. Mission life… pic.twitter.com/pSFPyLbVST

"XPoSat is the first dedicated satellite for polarization measurements in the medium X-Ray range and this is going to find something very interesting about blackholes and their ability to eat into other stars. Once black holes take raw material from adjacent stars, there will be X-Ray radiation. If you can measure the polarisation nature of the X-Ray emission, you can quantify the material ejection, such is the theory" explained Dr. S Somanath, Chairman, ISRO.

"The emissions from celestial objects such as black holes, neutron stars and other energetic events arise from intricate events and provide a formidable challenge to understand. To surmount this challenge, ISRO is gearing up to launch India's first polarimetry and spectroscopy satellite. The life of the mission is expected to be five years" ISRO said.

India's most-flown rocket, the #PSLV, which put #india among the few nations that launch foreign satellites (commercial missions), getting integrated and ready for its 60th launch on Monday, 1st Jan, 2024..
🚀9:10am 🚀
🚀🔥❤️🇮🇳#PSLVC58 #XPoSat #space #isro #science #tech pic.twitter.com/nY7KeeftlC

At the end of the 22-minute-long mission, the 469kg spacecraft would be placed in an orbit that is 650 km above the earth's surface. After placing the satellite in the intended orbit, the final stage of the PSLV rocket (PS4) would be brought down to a lower orbit of 350kms, by re-starting the engines on two instances. Once in the 350 km orbit, the fuels and hazardous chemicals stored within the upper stage tanks would be passivized. Passivization is a step that prevents any possible explosions or break-up of the stored chemicals. It is a step aimed at ensuring sustainable use of space.

Post-passivization, the PS4 stage of the PSLV rocket would be used as a stabilized orbiting platform, that would carry a handful of experiments and technology demonstrators from ISRO Centres, academia and startups. Such use of the 4th stage as a PSLV Orbital Experimental Module(POEM). As it circles the earth, the experiments onboard POEM can be activated to perform their respective tasks, thereby enabling a low-cost orbital platform to carry out such tasks. In contrast, launching a dedicated satellite for testing each of these experiments would be very expensive. Simply put, ISRO is re-purposing a spent rocket stage as an orbiting platform.

This launch would be the 60th flight of India's workhorse rocket, the Polar Satellite Launch Vehicle(PSLV), the vehicle undertaking next week's mission is designated PSLV-C58. The vehicle is the most-flown rocket in India's fleet. Flying since 1993, the rocket has an enviable track record of more than 98% success rate. PSLV is the rocket that is responsible for orbiting most of India's own satellites and the customer satellites launched by ISRO. It has earned the reputation of having successfully performed high-profile missions including Chandrayaan-1 and Mars Orbiter Mission, Aditya-L1.

Notably, this XPoSat mission would mark the third science mission launched by ISRO, in six months. On 14th July 2023, ISRO successfully launched the high-profile Chandrayaan-3 mission which delivered much more than initially expected and planned. On September 2nd, ISRO successfully launched the Aditya-L1 Spacecraft, the country's first solar observatory. The Aditya craft is expected to reach its destination in the first week of January 2024. In the first quarter of 2024, India's GSLV(formerly GSLV Mark2) rocket will be launching the NASA-ISRO Synthetic Aperture Radar(NISAR) Earth observation satellite, which is meant to help study the Earth's natural phenomena, climate change, landmass, icecaps, forest cover, oceans etc.