India Launches Chandrayaan-3: A Historic Success

Chandrayaan-3, a continuation of the Chandrayaan-2 mission, aims to showcase the complete capability of safe landing and roving on the lunar surface. It comprises a Lander module, a Propulsion module, and a Rover. The launch will be carried out by the LVM3 (Launch Vehicle Mark 3) from SDSC SHAR (Satish Dhawan Space Centre SHAR) in Sriharikota. The propulsion module will transport the lander and rover configuration to a lunar orbit of 100 km. Notably, the propulsion module includes the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload, which enables the study of spectral and polarimetric measurements of Earth from the lunar orbit.

The Lander payloads consist of the following:

• Chandra's Surface Thermophysical Experiment (ChaSTE): Measures thermal conductivity and temperature.
• Instrument for Lunar Seismic Activity (ILSA): Measures seismicity around the landing site.
• Langmuir Probe (LP): Estimates plasma density and its variations.
• Passive Laser Retroreflector Array (from NASA): Accommodated for lunar laser ranging studies.

The Rover payloads include:

• Alpha Particle X-ray Spectrometer (APXS): Used to derive the elemental composition near the landing site.
• Laser Induced Breakdown Spectroscope (LIBS): Enables chemical analysis of the lunar surface.

Chandrayaan-3 aims to develop and demonstrate technologies essential for interplanetary missions. The Lander will perform a soft landing on a predetermined lunar site and deploy the Rover for in-situ chemical analysis. The Propulsion Module carries the Lander from launch vehicle injection to the final lunar orbit, after which it separates. The GSLV-Mk3 launcher has been selected for Chandrayaan-3, placing the integrated module in an elliptic parking orbit. The mission objectives encompass demonstrating safe and soft landing, Rover mobility on the moon, and conducting in-situ scientific experiments.

The Lander incorporates advanced technologies such as altimeters (laser and RF-based), velocimeters (laser Doppler and horizontal velocity camera), inertial measurement (laser gyro-based referencing and accelerometer package), propulsion system (throttleable liquid engines and attitude thrusters), navigation, guidance, and control (including powered descent trajectory design), hazard detection and avoidance (camera and processing algorithm), and a landing leg mechanism. To validate these technologies, various tests have been planned and successfully conducted, including integrated cold tests, integrated hot tests, and lander leg mechanism performance tests using lunar simulant test beds to simulate different touchdown conditions.
 

Sources : ISRO