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Polar Satellite Launch Vehicle (PSLV) C-56

25th July, 2023 Science and Technology

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Context:  The Indian Space Research Organisation (ISRO) has announced that it will launch the PSLV-C56 rocket carrying Singapore’s DS-SAR satellite and six other payloads on July 30. The launch will take place from the Satish Dhawan Space Centre in Sriharikota at 6:30 a.m. IST.

Polar Satellite Launch Vehicle (PSLV)

  • PSLV is a remarkable achievement of Indian space technology. It is a versatile and reliable rocket that can launch various types of satellites into different orbits. It has a four-stage design, with alternating solid and liquid propellants.
  • The main objective of PSLV is to place Indian Remote Sensing (IRS) satellites into polar sun-synchronous orbits. These satellites are used for earth observation, disaster management, resource mapping and other applications.
  • PSLV has also demonstrated its capability to launch multiple satellites in a single mission, as well as to inject satellites into geostationary and interplanetary orbits.

Some of the most notable missions of PSLV are:

  • Chandrayaan-1: India's first lunar mission, launched in 2008. It carried an orbiter and an impactor that successfully reached the moon and performed scientific experiments.
  • Mars Orbiter Mission (MOM): India's first interplanetary mission, launched in 2013. It carried a spacecraft that entered the orbit of Mars and conducted various studies on the Martian atmosphere and surface.
  • Astrosat: India's first space observatory, launched in 2015. It carried a suite of instruments that observed the universe in different wavelengths, such as X-ray, ultraviolet and visible light.
  • Cartosat-2 series: A constellation of high-resolution earth imaging satellites. They provide data for cartography, urban planning, coastal land use, rural development and other purposes.
  • RISAT series: A constellation of radar imaging satellites. They provide all-weather and day-night surveillance of the earth's surface, especially for defence and security applications.

PSLV has established itself as a reliable and cost-effective launch vehicle for India and the world. It has earned a reputation for its accuracy, flexibility and innovation. It has also inspired many young Indians to pursue careers in science and technology.

PSLV-C56 Mission

  • The PSLV-C56 mission is an upcoming space mission by ISRO. The launch is scheduled for July 30, 2023.
  • The PSLV-C56 is a polar satellite launch vehicle that will carry seven satellites into a near-equatorial orbit (NEO).
    • The primary payload is the DS-SAR satellite, synthetic aperture radar (SAR) satellite developed by Singapore and Israel.
    • The other six satellites are co-passengers from various countries and organisations.
  • The PSLV-C56 is configured in its core-alone mode, which means it does not use solid rocket strap-on motors in its first stage. This makes it a flexible and adaptable launch vehicle that can cater to different mission requirements. The PSLV-C56 will lift off from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

DS-SAR satellite


  • The DS-SAR satellite, weighing 360 kg, is synthetic aperture radar (SAR) satellite that can provide high-resolution images of the Earth’s surface in all weather conditions and at any time of the day.
  • The satellite is designed and built by ST Engineering, a Singapore-based company, in collaboration with the National University of Singapore and DSO National Laboratories.
  • The PSLV-C56 rocket will inject the DS-SAR satellite into a near-equatorial orbit (NEO) at an inclination of 5 degrees and an altitude of 535 km. This orbit will enable the satellite to cover a large area of the Earth’s equatorial region.

Key points

  • DS-SAR carries a Synthetic Aperture Radar (SAR) payload developed by Israel Aerospace Industries (IAI), enabling all-weather day and night coverage with imaging at 1m resolution at full polarimetry.
  • The DS-SAR satellite will support the satellite imagery requirements of various agencies within the Government of Singapore, and ST Engineering will use it for commercial services, offering multi-modal and higher responsiveness imagery and geospatial services.
  • Along with DS-SAR, the PSLV-C56 will carry six co-passenger satellites:
    • VELOX-AM: A 23 kg technology demonstration microsatellite.
    • ARCADE: An experimental satellite for Atmospheric Coupling and Dynamics Explorer.
    • SCOOB-II: A 3U nanosatellite carrying a technology demonstrator payload.
    • NuLIoN: An advanced 3U nanosatellite enabling seamless IoT connectivity in both urban and remote locations.
    • Galassia-2: A 3U nanosatellite that will orbit at low earth orbit.
    • ORB-12 STRIDER: A satellite developed under international collaboration.

The launch of these satellites will contribute to further advancements in satellite technology and services.

Polar Satellite


  • Polar satellites are a type of artificial satellite that orbits the Earth in a north-south direction, passing over the poles as the Earth rotates on its axis. Unlike geostationary satellites, which stay in a fixed position above the equator, polar satellites can cover the entire surface of the Earth over time, making them useful for various applications such as mapping, weather observation, reconnaissance, and communication.
  • Polar satellites typically have a low Earth orbit (LEO), ranging from 500 to 800 km above the Earth's surface.
  • They have sensors and cameras that can capture various types of data, such as visible light, infrared, microwave, radar, and magnetometer. Some polar satellites also have thrusters or reaction wheels to control their orientation and altitude.

Applications of polar satellites

  • Mapping and surveying: Polar satellites can produce high-resolution maps of the Earth's topography, land use, vegetation, water resources, and natural disasters. They can also monitor changes in the environment over time, such as deforestation, urbanization, glacier melting, and sea level rise.
  • Weather observation: Polar satellites can measure various parameters of the weather and climate, such as temperature, humidity, pressure, wind speed, cloud cover, precipitation, and radiation. They can also track storms and cyclones and provide early warning systems for natural hazards.
  • Reconnaissance: Polar satellites can collect intelligence and surveillance data for military and security purposes. They can detect and monitor enemy activities, such as troop movements, missile launches, nuclear tests, and weapon facilities. They can also provide communication and navigation support for military operations.


  • Polar satellites play a crucial role in various fields, including meteorology, climate research, environmental monitoring, agriculture, disaster management, and natural resource assessment. They are part of a broader network of satellites that work together to provide comprehensive data for scientific research and practical applications on a global scale.

Must Read:

Polar Satellite Launch Vehicle (PSLV) C-55: https://www.iasgyan.in/daily-current-affairs/polar-satellite-launch-vehicle-pslv-c-55


Q. What is the primary purpose of Polar Satellites?

1. Studying distant galaxies and stars.

2. Providing internet connectivity in remote areas.

3. Monitoring and studying the Earth's surface and atmosphere.

4. Facilitating interplanetary travel.

How many of the above statements is/are correct?

A) Only 1

B) Only 2

C) Only 3

D) All

Explanation: B

Explanation: The correct Statement is 3. Monitoring and studying the Earth's surface and atmosphere. Polar Satellites are commonly used for Earth observation purposes, such as weather monitoring, climate research, environmental studies, and disaster management.