PSLV-C54 successfully places nine satellites in multiple orbits


    In News

    • Recently, ISRO’s PSLV-C54 successfully placed nine satellites which includes an Earth Observation Satellite (EOS-06) in multiple orbits.
      • This is the 56th flight of the Polar Satellite Launch Vehicle (PSLV) and the 24th flight of the PSLV-XL version.

    About the launch

    • The eight nano satellites includes:
      • ISRO Nano Satellite-2 for Bhutan (INS-2B)
      • Anand
      • Astrocast (four satellites)
      • Two Thybolt satellites.
    • EOS-6 is the Oceansat series’ third-generation satellite.
      • EOS-06 is envisaged to observe ocean colour data, sea surface temperature and wind vector data to use in oceanography, climatic and meteorological applications. 

    Upcoming missions

    • Aditya-L1: A coronagraphy spacecraft to study the solar atmosphere with a PSLV rocket. 
    • NavIC: ISRO will also launch a navigation satellite for the country’s NavIC constellation.

    Polar Satellite Launch Vehicle

    • It is the third generation launch vehicle of India.
    • It is the first Indian launch vehicle to be equipped with liquid stages.
    • After its first successful launch in October 1994, PSLV emerged as the reliable and versatile workhorse launch vehicle of India.
    • Difference: PSLV was developed to launch low-Earth Orbit satellites into polar and sun synchronous orbits whereas GSLV was developed to launch the heavier INSAT class of geosynchronous satellites into orbit.

    Types of orbits

    Geostationary orbit (GEO):

    • Satellites in geostationary orbit (GEO) circle Earth above the equator from west to east following Earth’s rotation.
    • This makes satellites in GEO appear to be ‘stationary’ over a fixed position.
    • GEO is used by satellites that need to stay constantly above one particular place over Earth, such as telecommunication satellites.

     Low Earth orbit (LEO):

    • A low Earth orbit (LEO) is an orbit that is relatively close to Earth’s surface. 
    • It is normally at an altitude of less than 1000 km but could be as low as 160 km above Earth.
    • Unlike satellites in GEO that must always orbit along Earth’s equator, LEO satellites do not always have to follow a particular path around Earth in the same way their plane can be tilted.

    Polar orbit and Sun-synchronous orbit (SSO):

    • Sun-synchronous orbit (SSO) is a particular kind of polar orbit. 
    • Satellites in SSO, traveling over the Polar Regions, are synchronous with the Sun. 
      • This means they are synchronized to always be in the same ‘fixed’ position relative to the Sun.
    • This means that the satellite will always observe a point on the Earth as if constantly at the same time of the day.

    Source: TH