What is the main task of India’s third moon mission which could not be achieved in its earlier missions? List the countries that have achieved this task. Introduce the subsystems in the spacecraft launched and explain the role of the ‘Virtual Launch Control Centre’ at the Vikram Sarabhai Space Centre, which contributed to its successful launch from Sriharikota.

The main task of India’s third Moon mission, Chandrayaan-3, was to achieve a safe and soft landing on the lunar surface, which could not be achieved in Chandrayaan-2.

Soft landing on the Lunar surface:

• Chandrayaan-3 made one of the closest approaches to the Moon’s South Pole by any lunar lander. Its landing site is located about 600 km from the Moon’s South Pole, on the near side of the Moon.
• Chandrayaan-2’s intended landing site was also in the south polar region. However, Chandrayaan-2’s Vikram lander lost communication during the final descent and could not achieve a soft landing.

Thus, Chandrayaan-3 fulfilled the key unfinished objective of Chandrayaan-2: demonstrating India’s capability for soft landing and rover operations on the lunar surface.

India has become the fourth country to achieve a soft landing on the moon after Russia (1966), the United States of America (1966) and China (2013).

Subsystems in Chandrayaan-3 Mission:

Chandrayaan-3 comprises three primary subsystems/modules:

• Propulsion Module (PM):
• Primary role:
  • Transport the Lander Module to the final 100 km circular lunar polar orbit.
  • Separates from the Lander Module once the lunar orbit is achieved, and subsequently operates independently for 3 to 6 months to perform Earth and Moon observations.
• Payload: Carries the SHAPE experiment to study spectral and polarimetric signatures of Earth from lunar orbit.
• Lander Module:
• Named Vikram, this is the core module responsible for achieving a soft landing on the lunar surface.
• Payloads:
  • ChaSTE: Measured temperature and thermal properties of the lunar surface near the polar region.
  • ILSA: Measured seismic activity around the landing site.
  • RAMBHA-LP and Atmosphere-Langmuir Probe: Measured nearsurface plasma density, including ions and electrons, and its variation with time.
  • Laser Retroreflector Array (from NASA): Instrument to measure distances via laser ranging and precise location marking of the lander.
• Rover:
• Named Pragyan, this is a 26-kg, six-wheeled solar-powered mobile platform (rover) designed to explore and analyse the lunar surface around the landing site.
• Payloads: APXS and LIBS to determine the elemental and chemical composition of lunar soil and rocks.

Role of VLCC in Chandrayaan-3 Launch:

Chandrayaan-3 was physically launched from Satish Dhawan Space Centre, Sriharikota. The Virtual Launch Control Centre (VLCC) at the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, acted as a remote launch-support and monitoring facility for the mission.

• Remote system check-outs: It enabled ISRO engineers at VSSC to remotely verify key launch vehicle systems before lift-off.
• Real-time Monitoring of launch vehicle health parameters related to electronics, propulsion systems, actuators, sensors, commands and telemetry.
• Support to LVM3 launch vehicle: VLCC helped the VSSC teams closely support the LVM3-M4 rocket used for Chandrayaan-3.
• Real-time coordination with Sriharikota: VLCC worked in coordination with the Launch Control Centre at SDSC-SHAR, ensuring quick technical inputs from domain experts.
• Provided an additional layer of monitoring and decision support, reducing operational risk during the launch countdown.
• Faster troubleshooting: Any anomaly in vehicle parameters could be analysed immediately by specialists at VSSC without requiring all experts to be physically present at Sriharikota.

VLCC functioned as a remote nerve centre for launch vehicle check-out, telemetry monitoring and technical decision support, contributing to the smooth and successful launch of Chandrayaan-3 from Sriharikota.