X-ray Polarimeter Satellite
X-ray Polarimeter satellite (XPoSat) in deployed configuration.jpg
X-ray Polarimeter satellite (XPoSat) in deployed configuration
Mission typeSpace observatory
Mission duration5 years (planned)[1]
Spacecraft properties
SpacecraftX-ray Polarimeter Satellite
BusModified IMS-2[1]
ManufacturerRaman Research Institute
Launch mass480 kg (1,060 lb)
Payload mass125 kg (276 lb)[2]
Dimensions65 × 65 × 60 cm (26 × 26 × 24 in)
Start of mission
Launch dateQ2 2023 (planned) [3]
Launch siteSatish Dhawan, First Launch Pad
ContractorIndian Space Research Organisation
Orbital parameters
Reference systemGeocentric orbit
RegimeLow Earth orbit
Altitude500–700 km (310–430 mi)[1]
Period90.0 minutes
Polarimeter Instrument in X-rays (POLIX)
X-ray Spectroscopy and Timing (XSPECT)

The X-ray Polarimeter Satellite (XPoSat) is a ISRO planned space observatory to study polarisation of cosmic X-rays. It is planned to be launched in Q2 2023 on a Small Satellite Launch Vehicle (SSLV),[4][5][3] with mission life of at least five years.[2]

The telescope is being developed by the Indian Space Research Organisation (ISRO) and the Raman Research Institute.


Studying how radiation is polarised gives away the nature of its source, including the strength and distribution of its magnetic fields and the nature of other radiation around it. XPoSat will study the 50 brightest known sources in the universe, including pulsars, black hole X-ray binaries, active galactic nuclei, and non-thermal supernova remnants.[2][6] The observatory will be placed in a circular low Earth orbit of 500–700 km (310–430 mi).[2][1]


Project began in September 2017 with ISRO grant of ₹95,000,000. Preliminary Design Review (PDR) of the XPoSat including the POLIX payload was completed in September 2018, followed by preparation of POLIX Qualification Model and beginning of some of its Flight Model components fabrication.[7]


Two payloads of XPoSat are hosted on a modified IMS-2 satellite bus.[2] Primary scientific payload is Polarimeter Instrument in X-rays (POLIX), which will study the degree and angle of polarisation of bright astronomical X-ray sources in the energy range 8-30 keV.[1][8] POLIX, a 125 kg (276 lb) instrument,[2] is being developed by the Raman Research Institute.[6][1][8][9] Its science objectives are to measure:[9]

Secondary payload is XSPECT (X-ray Spectroscopy and Timing), which will give spectroscopic information of soft X-rays in the energy range of 0.8-15 keV.[10]

See also


  1. ^ a b c d e f "ISRO announces Seven Mega Missions". GK Today. 20 May 2019. Retrieved 10 December 2021.
  2. ^ a b c d e f g "Future Exploration Missions of ISRO" (PDF). Dr. M. Annadurai, Director, ISAC, ISRO. UNCOPUOS 60th Session, Vienna, 2019. ISRO. Retrieved 10 December 2021.
  3. ^ a b "Government Of India, Department Of Space, Lok Sabha Unstarred Question No. 556 to be answered on Wednesday, July 20, 2022 about 'Private Participation In Space'" (PDF). 20 July 2022. Archived from the original (PDF) on 20 July 2022.
  4. ^ International Space Conference and Exhibition - DAY 3. Confederation of Indian Industry (video). 15 September 2021. Event occurs at 2:08:39–2:09:20. Retrieved 10 December 2021 – via YouTube.
  5. ^ Dutt, Anonna (17 September 2021). "India's first solar mission likely to launch next year: ISRO". The Hindustan Times. Retrieved 10 December 2021.
  6. ^ a b 5 Unique Space Science Missions That ISRO Will Be Flying in the Near Future Jatan Mehta The Wire 27 June 2019
  7. ^ "Raman Research Institute, Annual Report 2018-19" (PDF). Archived (PDF) from the original on 9 August 2020.
  8. ^ a b "Chandrayaan 2 launched: Here are future ISRO missions to space". The Indian Express. 22 July 2019. Retrieved 23 July 2019.
  9. ^ a b X-ray Polarimeter Experiment (POLIX) Raman Research Institute Accessed on 2 August 2019
  10. ^ "Government of India, Department of Space, Annual Report 2020" (PDF). Archived (PDF) from the original on 14 February 2020.