Q. With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statement(s) is/are correct?

  1. Other than USA and Russia, India is the only country to have launched a similar observatory into space.
  2. Astrosat is a 2000 kg satellite placed in an orbit at 1650 km above the surface of the Earth.

Select the correct answer using the codes given below.

  • 1 only
  • 2 only
  • Both1 and 2
  • Neither 1 nor 2

Answer: (d) Neither 1 nor 2

Astrosat
  • AstroSat is India’s first dedicated multi-wavelength space telescope.
  • It is the first dedicated Indian astronomy mission aimed at studying celestial sources in X-ray, optical, and UV spectral bands simultaneously.
  • AstroSat, with a lift-off mass of 1515 kg, was launched by the Indian launch vehicle PSLV from Satish Dhawan Space Centre, Sriharikota, on September 28, 2015, into a 650 km orbit inclined at an angle of 6 degrees to the equator.
  • The spacecraft control center at Mission Operations Complex (MOX) of ISRO Telemetry, Tracking and Command Network (ISTRAC), Bengaluru, manages the satellite during its entire mission life. 
  • The minimum useful life of the AstroSat mission is around 5 years.
  • Scientific Objectives:
    • To understand high energy processes in binary star systems containing neutron stars and black holes.
    • Estimate magnetic fields of neutron stars.
    • Study star birth regions and high energy processes in star systems lying beyond our galaxy.
    • Detect new briefly bright X-ray sources in the sky.
    • Perform a limited deep-field survey of the Universe in the Ultraviolet region.
XpoSat
  • 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.
    • This study is crucial for understanding the physics behind these celestial bodies.
  • Payloads:
    • 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.
  • Development:
    • Entirely built by two Bengaluru-based institutes—ISRO’s UR Rao Satellite Centre and Raman Research Institute—XPoSat’s development began in 2008, with a formal agreement signed with ISRO in 2015.
  • Global Context:
    • XPoSat is only the world’s second mission dedicated to X-ray polarization in the medium X-ray band. NASA’s Imaging X-ray Polarimetry Explorer (IXPE), launched in 2021, was the first such mission by a space agency.
  • National Contribution:
    • XPoSat will be India’s third space-based observatory, following the recently launched solar mission Aditya-L1 and AstroSat, which was launched in 2015. Its launch is seen as a significant stride for Indian astronomy and space research.