Chandrayaan-4 Mission

Context: India is set to launch the Chandrayaan-4 Mission in 2027, marking a significant step in the nation’s space exploration efforts.

Relevance of the Topic:Prelims: Key facts about Chandrayaan-4 mission. 

Chandrayaan-4 Mission

• Chandrayaan-4 is a planned lunar sample return mission expected to launch around 2027.
• Initiative of: Indian Space Research Organisation. Fourth iteration in Chandrayaan lunar series. 

• Aim: To collect samples from the moon's surface and bring them back to the Earth.
• Landing site: planned near Statio Shiv Shakti (landing site of Chandrayaan-3) located near to the lunar south pole region.

Spacecraft Design and Mission: 

1. Design: 

• The spacecraft would comprise five modules across two separate launches, onboard two separate Launch Vehicle Mark-3 (LVM-3) launch vehicles.
  • Ascender Module (AM), Descender Module (DM) in one launch. 
  • Re-entry Module (RM), Transfer Module (TM), and Propulsion Module (PM) in second launch.
• After two launches, the stacks will be docked together in elliptical Earth orbit to form an integrated stack. 

2. Lunar landing: 

• Subsequent to docking, the Integrated Stack will perform the first set of Earth-bound maneuvers with the PM propulsion system.
  • In the final lunar orbit, DM + AM will get separated from TM + RM. 
  • DM + AM will undergo powered descent to achieve soft landing on the lunar surface.
• After lunar landing, a robotic arm (Surface Sampling Robot) will scoop around 2-3 kg samples around the landing site. Additionally, a drilling mechanism will collect sub-surface samples. The samples will be sealed and brought back to Earth. 

3. Re-Entry into Earth’s Atmosphere:

• Once sample collection is completed, AM would ascend to the lunar orbit and dock with the parked TM + RM. 
• Samples will be transferred from AM to RM. After sample transfer, the TM + RM will be undocked from AM. Later, the TM + RM will perform maneuvers to return to Earth. 
• At a suitable entry corridor, RM would get separated from TM and perform ballistic re-entry into Earth’s atmosphere and finally land onto Earth along with Lunar Sample.

Challenges:

• Demonstration of successful docking capabilities in the Earth’s orbit and undocking in the lunar orbit. 
• Successful re-entry into the Earth’s atmosphere by withstanding intense heat and pressure. 
• Preserving the lunar samples in an uncontaminated state on their way back to Earth. 

Significance: 

• The mission will validate critical processes such as docking and undocking in lunar orbit, precise landing techniques, and the safe return of spacecraft through Earth's atmosphere. 
• By mastering these technologies, Chandrayaan-4 will directly contribute to the development of systems required for India's planned crewed lunar landing in 2040.

Lunar Missions by ISRO:

1. Chandrayaan-1: 

• India's first moon mission launched in 2008. 
• Launch vehicle: Polar Satellite Launch Vehicle (PSLV)
• Success:
  • The spacecraft orbited around the Moon at a height of 100 km. It mapped the Moon in infrared, visible, and X-ray light from lunar orbit and used reflected radiation to prospect for various elements, minerals, and ice.
  • It released an impactor (Moon Impact Probe- MIP) that studied the thin lunar atmosphere before crashing on the Moon’s surface. 
  • The mission gave definitive proof of the presence of water ice in the Moon’s atmosphere and surface.

2. Chandrayaan-2: 

• Second moon mission launched in 2019. 
• Launch vehicle: Launch Vehicle Mark-3 (LVM-3)
• The spacecraft consisted of an orbiter, a lander, and a rover. 
• The orbiter circled the Moon in a polar orbit at a height of 100 km and has a planned mission lifetime of seven and a half years. 
• Success:
  • The mission’s Vikram lander was planned to land on the moon (demonstrate soft landing). However, the lander crashed due to a software error.
  • Despite the loss of communication with Vikram Lander, 90-95% of the mission objectives have been accomplished.
  • It has enriched understanding of the Moon's evolution and mapped minerals and water molecules in the Polar Regions.

3. Chandrayaan-3: 

• Third moon mission launched in 2023. 
• Launch vehicle: Launch Vehicle Mark-3 (LVM3)
• The spacecraft consists of a Vikram lander and a Pragyan rover. The Vikram lander touched down on the Moon on August 23, 2023. 
• Success:
  • Chandrayaan-3 made one of the closest approaches to the moon's South Pole.
  • The landing site is located about 600 kilometers from the South Pole of the Moon, on the near side of the Moon. 
  • The rover operated for one lunar day (approximately 14 Earth days). It aimed to collect lunar samples, do in-situ experiments and send data to Vikram lander, to transmit it back to Earth for comprehensive analysis.
  • India became the fourth country to have landed a spacecraft on the Moon—after the United States, Russia, and China.