Central Idea

The Indian Space Research Organisation (ISRO) is partnering with the Raman Research Institute (RRI) in Bengaluru to develop the X-Ray Polarimeter Satellite (XPoSat), set to launch later this year.

What is XPoSat?

XPoSat aims to study various dynamics of bright astronomical X-ray sources in extreme conditions.
It is India’s first polarimetry mission and the world’s second, with NASA’s Imaging X-ray Polarimetry Explorer (IXPE) being the other major mission launched in 2021.
IXPE carries three state-of-the-art space telescopes to observe polarized X-rays from neutron stars and supermassive black holes, providing insights into the geometry and inner workings of the light source.

XPoSat will carry two scientific payloads in a low Earth orbit.
The primary payload, POLIX, will measure the polarimetry parameters of X-rays, observing approximately 40 bright astronomical sources across different categories during the mission’s planned five-year lifetime.
The XSPECT (X-ray Spectroscopy and Timing) payload will provide spectroscopic information on how light is absorbed and emitted by objects, allowing observations of X-ray pulsars, black hole binaries, low-magnetic field neutron stars, and more.

X-rays in space have higher energy and shorter wavelengths, ranging from 0.03 to 3 nanometers.
X-rays are emitted by objects with temperatures in the millions of degrees Celsius, such as pulsars, galactic supernova remnants, and black holes.
Polarized light, consisting of organized moving electric and magnetic waves, plays a role in X-ray observations, and polarized lenses are used by fishermen to reduce glare from sunlight.

Polarimetry involves measuring the angle of rotation of the plane of polarized light as it passes through certain transparent materials.
XPoSat’s primary payload, POLIX (Polarimeter Instrument in X-rays), developed by RRI and UR Rao Satellite Centre, will measure the degree and angle of polarization in X-rays from astronomical sources.
The emission mechanisms of various astronomical sources are complex, and understanding them poses challenges that polarimetry can help address.