The Indian Space Research Organisation (ISRO) accomplished a major milestone by successfully placing its first polarimetry mission, the X-ray Polarimeter Satellite (XPoSat), into a precise circular orbit of 650 km on Monday morning after a 21-minute flight. This achievement marks the world’s second satellite-based mission exclusively dedicated to making X-ray polarimetry measurements.
Here’s a breakdown of the XPoSat mission and its significance:
What is XPoSat?
XPoSat focuses on analyzing the polarization of X-rays emitted by bright celestial sources in the medium frequency band.
The mission comprises two payloads, the Indian X-ray Polarimeter (POLIX) and X-ray Spectroscopy and Timing (XSPECT), built by the Raman Research Institute and UR Rao Satellite Centre in Bengaluru.
It is designed for observation from a low earth orbit (~650 km, low inclination of ~6 degrees) and boasts an estimated mission life of about five years.
Scientific Payloads on XPoSat:
POLIX: Operates in the medium X-ray energy band of 8 to 30 kilo electron Volt (keV) and features a collimator and four X-ray proportional counter detectors. It observes a few tens of astronomical sources.
XSPECT: Conducts fast timing and high spectroscopic resolution in a soft X-ray energy band (0.8-15 keV) and observes various sources like X-ray pulsars, black hole binaries, and more.
Why is XPoSat Significant?
The mission marks a groundbreaking effort in enabling X-ray polarisation measurements from bright sources in the medium energy band, a novel endeavor never previously attempted.
XPoSat aims to observe magnetars, black holes, neutron stars, and other celestial entities emitting polarized X-rays. By studying these emissions, scientists can glean insights into radiation nature and associated processes.
Importance of X-ray Polarisation Studies:
Polarised X-rays carry vital information about the sources emitting them and the intricate processes they undergo, offering clues about celestial bodies and phenomena.
While missions dedicated to X-ray polarisation measurements have been limited globally, XPoSat’s unique capabilities represent a significant leap in advancing our understanding of cosmic radiations.
The field of X-ray polarimetry is challenging due to the development of sensitive and precise instruments. However, initiatives like XPoSat and missions by global counterparts, such as NASA’s Imaging X-ray Polarimetry Explorer (IXPE), mark significant strides in unlocking the mysteries of the universe through X-ray observations.
The successful deployment of XPoSat signifies India’s pioneering efforts in space research and contributes significantly to the global pursuit of unraveling the enigmatic cosmos through precise X-ray polarisation measurements.