Why in News?
India’s third mission to the moon – Chandrayaan-3 – will be taken off on 14th July, 2023. The mission aims to achieve what its predecessor – Chandrayaan-2 could not – land softly on the lunar surface and explore it with a rover. A last-minute glitch led to the failure of the lander’s (Vikram) soft landing attempt after a successful orbital insertion.
About Chandrayaan-3
Chandrayaan-3 is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface. It consists of Lander and Rover configuration. It will be launched by LVM3 from SDSC SHAR, Sriharikota. The propulsion module will carry the lander and rover configuration till 100 km lunar orbit. The propulsion module has Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and Polari metric measurements of Earth from the lunar orbit.
Key differences between Chandrayaan-2 and Chandrayaan-3
1. Even as the mission architecture remains the same, there are certain differences between the two missions. The biggest difference between the two missions is in what’s being taken onboard the GSLV-MkIII rocket. While Chandrayaan-2 comprised of Vikram lander, Pragyan rover, and an orbiter, Chandrayaan-3 will launch with just a lander and a rover.
2. The Chandrayaan-3 lander mission is equipped with “lander hazard detection and avoidance cameras” for coordination with the orbiter and the mission control during the landing process on the surface of the Moon. While Chandrayaan-2 had just one such camera, Chandrayaan-3 has been fitted with two such cameras, as per an India Today report.
3. Furthermore, the Vikram lander will have stronger legs than the previous version. The landing velocity has been increased from 3m/second to 2m/second, ISRO chairman S Somanath told Times of India. “That means even at 3m/sec, the lander will not crash or break (its legs),” Somanath added.
4. Another change is the addition of more fuel to Vikram so it has more capability to travel or handle dispersion. Furthermore, a new sensor has also been added. “We have added a new sensor called the laser doppler velocity metre, which will look at the lunar terrain. And through laser source sounding, we will be able to get components of three velocity vectors. We will be able to add this to the other instruments available, thereby creating redundancy in measurement,” Somanath told TOI.
5. The ISRO chief had earlier shared details about what went wrong with the Vikram lander of Chandrayaan-2 as it went hurtling down towards the identified 500m x 500 m landing spot on the lunar surface with the engines designed to reduce its velocity developing higher thrust than expected. This time, Somanath stated that the area of landing has been expanded from 500m x 500m to four km by 2.5 km.
Comparing Chandrayaan 2 and 3 Missions
Chandrayaan-3 Payloads:
- The propulsion module: It has Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload to look for smaller planets that might be habitable in the reflected light.
- Lander payloads: It will have 4 payloads –
- Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) – a passive experiment (from NASA) to help accurately measure the distance between Earth and moon.
- Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure the thermal conductivity and temperature;
- Instrument for Lunar Seismic Activity (ILSA) for measuring the seismicity around the landing site;
- Langmuir Probe (LP) to estimate the plasma density and its variations.
- Rover payloads: Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS) for deriving the elemental composition in the vicinity of the landing site.
Changes in the Mission Design:
- Expanded Landing Area: Chandrayaan-3 has been given instructions to land safely anywhere in a 4kmx2.4km area, unlike the specific 500mx500m patch targeted by Chandrayaan-2.
- Increased Fuel Capacity: The lander in Chandrayaan-3 has been provided with more fuel to travel longer distances to the landing site or an alternate landing site.
- Enhanced Landing Site Determination: Instead of relying solely on pictures taken during descent, high-resolution images from Chandrayaan-2’s orbiter have been used to feed the lander with location information.
- Modified Lander Structure: Changes have been made to the lander’s physical structure, including the removal of one thruster, strengthening of the legs for higher velocity landings, and the addition of more solar panels.
FAQs related to the comparison between Chandrayaan-3 and Chandrayaan-2
A1: The main objective of Chandrayaan-3 is to successfully land softly on the lunar surface and explore it with a rover, which Chandrayaan-2 was not able to achieve due to a landing failure.
A2: The key differences include the payloads carried, with Chandrayaan-3 having a lander with stronger legs, more fuel capacity, additional hazard detection cameras, and new sensors. The landing area has also been expanded, and the mission design has been modified based on the lessons learned from Chandrayaan-2.
A3: The lander of Chandrayaan-3 has stronger legs to withstand higher landing velocities, increased fuel capacity for longer travel distances, and the addition of a laser doppler velocity meter and other sensors for improved measurements and redundancy.
A4: Chandrayaan-3 has expanded the landing area to a 4kmx2.4km region, compared to the specific 500mx500m patch targeted by Chandrayaan-2. High-resolution images from Chandrayaan-2’s orbiter are also being used to provide more accurate location information to the lander.
Read also:- Chandrayaan 3
Chandrayaan-3 vs Chandrayaan-2: A Comparison of India’s Moon Missions,Chandrayaan-3 vs Chandrayaan-2: A Comparison of India’s Moon Missions,Chandrayaan-3 vs Chandrayaan-2: A Comparison of India’s Moon Missions
