'Even If Everything Fails...': ISRO Chief Says Chandrayaan-3 Prepared For Soft Landing On Moon Against Potential Odds

Vikram, the lander of India's Chandrayaan-3 lunar mission, has been designed to achieve a soft landing on the Moon's surface on 23 August, even in the event of sensor and engine failures.

This was stated by Indian Space Research Organisation (ISRO) chairman S Somanath during a talk on the mission, hosted by the non-profit organisation Disha Bharat.

The design of the lander, Vikram, has been carefully crafted to withstand any failures that may occur. The chairman emphasised that the mission has been designed to ensure a successful landing, even if all sensors fail to function.

The only condition is that the propulsion system must work properly, as reported by a news wire agency.

Chandrayaan-3 was launched into space on 14 July and successfully entered lunar orbit on 5 August. To bring Vikram closer to the Moon's surface for landing, three additional de-orbiting maneuvers will be performed.

The mission aims to achieve a soft landing on the Moon's surface on 23 August.

The de-orbiting manoeuvres will be conducted on 9 August, 14 August, and 16 August in order to reduce the spacecraft's orbit to 100 km x 100 km around the Moon, according to Somanath.

Following the "de-boost" process, which slows down the craft, a separation exercise for the lander propulsion module will be carried out. This will be followed by the landing on the lunar surface on 23 August, as explained by Somanath.

The ISRO chairman reassured that the design of the Vikram lander ensures that it can still land even if two of its engines do not work.

The entire design of Vikram has been carefully planned to handle multiple failures, as long as the algorithms function properly, he added.

The ISRO team's main challenge, as stated by Somanath, is to successfully land the horizontal 'Vikram' on the lunar surface in a vertical position.

Once the lander separates from the orbiter, it will initially move horizontally. However, a series of manoeuvres will be executed to bring it into a vertical stance, ensuring a safe landing on the Moon.

The successful completion of this task is crucial, given that ISRO was unable to land the lander safely on the Moon during the Chandrayaan-2 mission.

Somanath emphasised the importance of being able to transition from a horizontal to a vertical direction, as this was the specific challenge faced during the previous attempt.

The challenge at hand is to ensure that the fuel consumption is minimised, the distance calculations are accurate, and all algorithms are functioning properly, as stated by the ISRO chief.

To address potential variations in calculations, the ISRO team has made preparations for Vikram to attempt a proper landing, as explained by Somanath.

The lander will be equipped with four payloads. ChaSTE, or Chandra's Surface Thermo-Physical Experiment, will measure the thermal properties of the lunar surface near the polar region.

The RAMBHA-LP payload will measure the density of near surface plasma (ions and electrons) and its changes over time. Additionally, a laser retro-reflector array from NASA will allow for precise positioning measurements of the lander on the lunar surface by future orbiters.

Lastly, an Instrument for lunar seismic activity will be included.

The rover, named 'Pragyan', will carry three payloads. One of these is the Laser Induced Breakdown Spectroscope, which will analyse the elemental composition of lunar soil and rocks near the landing site.

Another payload on the rover is the Alpha Particle X-Ray Spectrometer. This instrument will determine the chemical composition of the lunar surface and provide valuable insights into its mineralogy.

Pragyan also includes an experimental payload called Spectro-polarimetry of Habitable Planet Earth or SHAPE. This payload will study the spectro-polarimetric signature of Earth, specifically focusing on its habitable aspects, in the near-infrared wavelength range.