XPoSat – X-ray Polarimeter Satellite

XPoSat (X-ray Polarimeter Satellite) is the first polarimetry and third observatory space mission of India. The main objective is to study astronomical objects like black holes through this mission. The XPoSat satellite was launched by ISRO at 09:10 Hrs IST (03:40 Hrs GMT) on January 1, 2024, from Satish Dhawan Space Centre by using a PSLV-C58 launching vehicle.

In this article, we will discuss the XPoSat (X-ray Polarimeter Satellite) mission with its components, objectives, and future projections.

XPoSat – X-ray Polarimeter Satellite

What Is XPoSat (X-ray Polarimeter Satellite)?

XPoSat (X-ray Polarimeter Satellite) is a joint mission of ISRO and Raman Research Institute to study the emission and polarisation of astronomical X-rays in extreme space conditions for the next five years. The satellite will study the X-ray polarization effects in the medium X-ray band. It will give an insight into the physics works behind the celestial bodies, like Black holes, Neutron stars, and Magnetars.

Development Authorities of XPoSat (X-ray Polarimeter Satellite)

The development process of the XPoSat started in 2008. In 2015 the full-fledged development started with a formal agreement between ISRO and a Bengaluru-based research institute. Here are the details:

• ISRO’s UR Rao Satellite Centre (URSC) – It is a leading wing of ISRO which develops and constructs new satellite technologies.
• Raman Research Institute – The institute was founded by Indian physicist C. V. Raman to study the different areas of physics.

Mission Objectives Of The XPoSat (X-ray Polarimeter Satellite)

The satellite configuration has been modified by using the IMS-2 bus platform. It is a mainframe systems based process on the heritage of Indian Remote Sensing (IRS) satellites. Here are the major and important objectives of The XPoSat mission as mentioned below:

• Measure the polarisation of the X-rays that have an energy band of 8 to 30 keV.
• To study approximately 50 potential cosmic sources based on Thomson Scattering.
• Sustain a long-term spectral and temporal study of the X-rays by the celestial bodies.
• It will also observe two types of sourcess like persistent sources and transient sources.
• It will help us with a detailed understanding of the galactic black hole binary sources.

Payloads Of XPoSat (X-ray Polarimeter Satellite)

XPoSat carried two major payloads that will study the emission and polarisation of astronomical X-rays in extreme space conditions. Lets dive into the details.

POLIX – The Primary Payload Of XPoSat (X-ray Polarimeter Satellite)

POLIX is an X-ray Polarimeter instrument that will study the X-ray in between 8 to 30 keV.

• This payload has been developed by Raman Research Institute (RRI).
• The payload is made of a collimator with a scatterer and four X-ray proportional counter detectors.
• The scatterer is surrounded by those four X-ray proportional counter detectors.
• For the low atomic mass, the scatterer can create anisotropic Thomson scattering by using incoming X-rays.
• The collimator’s view is 3 degrees x 3 degrees with a bright source.
• It is expected that the payload will be able to observe and capture around 40 bright astronomical sources from different categories.
• This is the first payload developed in the medium X-ray energy band to perform polarimetry measurements in extreme space conditions.

XSPECT – The Secondary Payload Of XPoSat (X-ray Polarimeter Satellite)

XSPECT is an X-ray SPECtroscopy and Timing Payload that can provide soft X-rays in a fast time frame with spectroscopic resolution.

• It will record, examine, and perform long-term monitoring of the spectral state changes.
• The payload will monitor the line flux and profile the different spectral state changes.
• XSPECT will do temporal monitoring emission of soft X-rays on a long-term basis.
• It will track the source and background of different types of X-rays, blackhole binaries, and the low-magnetic field neutron star (NS).
• Passive collimators installed in POLIX will reduce the background to narrow the field view of the XSPECT.

How will XPoSat Study the Celestial Objects?

To understand the working structure of XPoSat, we need to understand those two fundamental principles first, on which XPoSat was developed by ISRO and RRI.

Electromagnetic Radiation – It is a phenomenon where an electric field and a magnetic field vibrate perpendicular.

Polarisation of Electromagnetic Radiation – It the orientation an electric field and a magnetic fields as the radiation moves through space.

Now, lets dicuss how XPoSat will study the Celestial Objects.

X-ray is an electromagnetic radiation with a wavelength of 0.01 to 10 nanometres. They can be polarised after they get scattered.

• With a scatterer and four X-ray proportional counter detectors, the POLIX will create Anisotropic Thomson Scattering by from incoming X-rays of Black holes, Neutron stars, and Magnetars.
• XSPECT will record, examine, and perform long-term monitoring of the changes in spectra. It will line flux track the background of different types of X-rays.
• Passive collimators installed in POLIX will collaborate with XSPECT to reduce the background by narrowing the field view of it.

Final Destination – XPoSat (X-ray Polarimeter Satellite)

XPoSat (X-ray Polarimeter Satellite) successfully became a part of the ‘Gaganyaan year’. This mission will study the cosmic nature of neutron stars, black holes, active galactic nuclei, and supernovae. The PSLV – C58 carried carried the XPoSat and Ten other satellites. They all have been deployed in low earth orbits.

PSLV C58 and PS4 Stage – XPoSat Mission

PSLV-C58 is the 4th PSLV-DL and 60th PSLV that was launched by ISRO at 09:10 Hrs IST (03:40 Hrs GMT) on January 1, 2024, from Satish Dhawan Space Centre. The PSLV Orbital Experimental Module-3 or POEM-3 is a scientific experiment which discards the PS4 stage of PSLV-CA. It is also known as the PSLV Stage 4 Orbital Platform (PS4-OP). Here are the name of those 10 payloads were launced with XPoSat as mentioned below:

PS4 Stage – XPoSat Mission
Payload Name	Development Authority
Radiation Shielding Experimental Module (RSEM)	TakeMe2Space
Women Engineered Satellite (WESAT)	LBS Institute of Technology for Women
BeliefSa-t0 Amateur radio satellite	K.J. Somaiya Institute of Technology
Green Impulse TrAnsmitter (GITA)	Inspecity Space Labs Private Limited
Technology Demonstrator (LEAP-TD)	Dhruva Space Private Limited
RUDRA 0.3 HPGP	Bellatrix Aerospace Private Limited
ARKA-200	Bellatrix Aerospace Private Limited
Dust Experiment (DEX)	PRL
ISRO Fuel cell Power System (FCPS)	VSSC, ISRO
ISRO and Si-based High Energy cell	VSSC, ISRO

FAQs – XPoSat (X-ray Polarimeter Satellite)

What is the use of X-ray polarimeter satellite?

XPoSat (X-ray Polarimeter Satellite) is a joint mission of ISRO and Raman Research Institute to study the emission and polarisation of astronomical X-rays in extreme space conditions for the next five years.

What is the first polarimeter satellite?

NASA’s Imaging X-ray Polarimetry Explorer (IXPE) is the first polarimeter satellite.

Why is XPoSat launched?

XPoSat launched to study the emission and polarisation of astronomical X-rays in extreme space conditions.

What is the new mission of ISRO?

Shukrayaan 1 or Venus Orbiter Mission will be India’s first mission to Venus. The expected launch date is December 2024 or 2025.

How many satellites are launched by ISRO with XPoSat?

The PSLV – C58 carried carried the XPoSat and Ten other satellites. They all have been deployed in low earth orbits.