ISRO’s fully integrated PSLV-C58 launch vehicle on the launchpad

ISRO is set to launch its first mission of 2024, XPoSAT on January 1, 2024 with the aim to study the universe, especially the Black Holes. Read to know the launch date, time, aim and other details of the XPoSAT Mission

New Delhi: Looking back at the year 2023 in terms of the nation’s success, one of the first things that may crop up in one’s mind, are the successful missions of the Indian Space Research Organisation (ISRO). After creating history with Chandrayaan-3 and successfully launching its first solar mission, Aditya-L1, ISRO is ready to begin 2024 with a bang. The Space Organisation is ready to launch India’s first dedicated polarimetry mission to study various dynamics of bright astronomical X-ray sources in extreme conditions – XPoSAT on January 1, 2024. Read further to know what is XPoSAT, XPoSAT launch date and time, XPoSAT Mission objectives and other such important details.

ISRO Ready To Launch XPoSAT

As mentioned earlier, the Indian Space Research Organisation (ISRO) is planning to launch the XPoSAT Mission on January 1, 2024. If this mission is successful, India will become the second country in the world to launch an advanced astronomy observatory to study the various dynamics of bright astronomical X-ray sources in extreme conditions, especially black holes and neutron stars.

According to the website, ISRO’s PSLV-C58 Mission is to launch XPOSAT Satellite into an Eastward low inclination orbit. After injection of XPOSAT, the PS4 stage will be re-started twice to reduce the orbit into 350 km circular orbit to maintain in 3-axis stabilized mode for Orbital Platform (OP) experiments.

What Is ISRO’s Latest XPoSAT Mission?

According to the official website of the Indian Space Research Organisation (ISRO), XPoSat (X-ray Polarimeter Satellite) 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 primary payload POLIX (Polarimeter Instrument in X-rays) will measure the polarimetry parameters (degree and angle of polarization) in 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.

What Will XPoSAT Mission Do?

Speaking about why is this mission being launched, the ISRO website is quoted as saying, the emission mechanism from various astronomical sources such as blackhole, neutron stars, active galactic nuclei, pulsar wind nebulae etc. originates from complex physical processes and are challenging to understand. While the spectroscopic and timing information by various space based observatories provide a wealth of information, the exact nature of the emission from such sources still poses deeper challenges to astronomers. The polarimetry measurements add two more dimension to our understanding, the degree of polarization and the angle of polarization and thus is an excellent diagnostic tool to understand the emission processes from astronomical sources. The polarimetric observations along with spectroscopic measurements are expected to break the degeneracy of various theoretical models of astronomical emission processes. This would be the major direction of research from XPoSat by Indian science community

XPoSAT Mission Objectives

The objectives of this mission are:

To measure polarisation of X-rays in the energy band 8-30keV emanating from about 50 potential cosmic sources through Thomson Scattering by POLIX payload.

To carry out long term spectral and temporal studies of cosmic X-ray sources in the energy band 0.8-15keV by XSPECT payload.

To carry out polarisation and spectroscopic measurements of X-ray emissions from cosmic sources by POLIX and XSPECT payloads respectively in the common energy band.

XPoSAT Mission Payloads

The XPoSAT Mission carries two payloads namely POLIX (Polarimeter Instrument in X-rays) and XSPECT (X-ray Spectroscopy and Timing). POLIX is realized by Raman Research Institute and XSPECT is by Space Astronomy Group of URSC.

As per the website, POLIX is an X-ray Polarimeter for astronomical observations in the energy band of 8-30 keV. The payload is being developed by Raman Research Institute (RRI), Bangalore in collaboration with U R Rao Satellite Centre (URSC). The instrument is made of a collimator, a scatterer and four X-ray proportional counter detectors that surrounds the scatterer. The scatterer is made of low atomic mass material which causes anisotropic Thomson scattering of incoming polarised X-rays. The collimator restricts the field of view to 3 degree x 3 degree so as to have only one bright source in the field of view for most observations. POLIX is expected to observer about 40 bright astronomical sources of different categories during the planned lifetime of XPoSat mission of about 5 years. This is the first payload in the medium X-ray energy band dedicated for polarimetry measurements.

While XSPECT, is an X-ray SPECtroscopy and Timing payload onboard XPoSat, which can provide fast timing and good spectroscopic resolution in soft X-rays. Taking advantage of the long duration observations required by POLIX to measure X-ray polarization, XSPECT can provide long-term monitoring of spectral state changes in continuum emission, changes in their line flux and profile, simultaneous long term temporal monitoring of soft X-ray emission in the X-ray energy range 0.8-15 keV. An array of Swept Charge Devices (SCDs) provide an effective area >30 cm2 at 6 keV with energy resolution better than 200 eV at 6 keV. Passive collimators are used to reduce the background by narrowing the field of view of XSPECT. XSPECT would observe several types of sources viz X-ray pulsars, blackhole binaries, low-magnetic field neutron star (NS) in LMXBs, AGNs and Magnetars.