Chandrayaan-3 Mission

Context:

Recently, the Department of Science has stated that India plans to execute the Chandrayaan-3 mission in August 2022.

Chandrayaan-3 Mission

• Chandrayaan-3 is a planned third lunar exploration mission by the Indian Space Research Organisation (ISRO).
• Following Chandrayaan-2, where a last-minute glitch in the soft landing guidance software led to the failure of the lander’s soft landing attempt after a successful orbital insertion, another lunar mission for demonstrating soft landing was proposed.
  • The subsequent failure of the Vikram lander led to the pursuit of another mission to demonstrate the landing capabilities needed for the Lunar Polar Exploration Mission proposed in partnership with Japan for 2024.
• Chandrayaan-3 will be a mission repeat of Chandrayaan-2 but will only include a lander and rover similar to that of Chandrayaan-2.
• It will not have an orbiter.
• The spacecraft is planned to be launched in August 2022.
• The rocket for the launch of the spacecraft was declared ready and awaits the module

Background

• In the second phase of the Chandrayaan programme to demonstrate soft landing on the Moon, ISRO launched Chandrayaan-2 onboard a GSLV Mk III launch vehicle consisting of an orbiter, a lander and a rover. The lander was scheduled to touchdown on the lunar surface in September 2019 to deploy the Pragyan rover.
• Earlier reports had emerged about a collaboration with Japan on a mission to the lunar south pole where India would be providing the lander while Japan would provide both launcher and rover.
• The mission may include site sampling and lunar night survival technologies.

Chandrayaan-2 Mission

• Chandrayaan-2 consisted of an Orbiter, Lander and Rover, all equipped with scientific instruments to study the moon.
  • The Orbiter would watch the moon from a 100-km orbit, while the Lander and Rover modules were to be separated to make a soft landing on the moon’s surface.
  • ISRO had named the Lander module as Vikram, after Vikram Sarabhai, the pioneer of India’s space programme, and the Rover module as Pragyaan, meaning wisdom.
• It was sent aboard the country’s most powerful geosynchronous launch vehicle, the GSLV-Mk 3.
• However, lander Vikram, instead of a controlled landing, ended up crash-landing and prevented rover Pragyaan from successfully travelling on the surface of the moon.

GSLV-Mk 3

• Geosynchronous Satellite Launch Vehicle Mark-III was developed by Indian Space Research Organisation (ISRO), is a three-stage vehicle, designed to launch communication satellites into geostationary orbit.
• It has a mass of 640 tonnes that can accommodate up to 8,000 kg payload to Low Earth Orbit (LEO) and 4000 kg payload to GTO (Geo-Synchronous Transfer Orbit).

What are the Different Types of Orbits?

Polar Orbit

• A polar orbit travels north-south over the poles and takes approximately 90 minutes for a full rotation.
• These orbits have an inclination near 90 degrees. This allows the satellite to see virtually every part of the Earth as the Earth rotates underneath it.
• These satellites have many uses such as monitoring crops, global security, measuring ozone concentrations in the stratosphere or measuring temperatures in the atmosphere.
• Almost all the satellites that are in a polar orbit are at lower altitudes.
• An orbit is called sun-synchronous when the angle between the line joining the centre of the Earth and the satellite and the Sun is constant throughout the orbit.
• These orbits are also referred to as “Low Earth Orbit (LEO)” which enables the onboard camera to take images of the earth under the same sun-illumination conditions during each of the repeated visits, thus making the satellite useful for earth resources monitoring.
• It passes over any given point on Earth’s surface at the same local solar time.

Geosynchronous Orbit

• Geosynchronous satellites are launched into orbit in the same direction the Earth is spinning and can have any inclination.
• When the satellite is in orbit at a specific altitude (approximately 36,000km above the Earth’s surface), it will exactly match the rotation of the Earth.
  • While, Geostationary orbits fall in the same category as geosynchronous orbits, but with that one special quality of being parked over the equator.
• In the case of geostationary satellites, the Earth’s force of gravity is exactly enough to provide acceleration required for circular motion.
• Geosynchronous Transfer Orbit(GTO): To attain geostationary or geosynchronous earth orbits, a spacecraft is first launched into a Geosynchronous Transfer Orbit.
  • From the GTO the spacecraft uses its engines to shift to geostationary or geosynchronous orbit.

Source: The Hindu

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