Moon has always been a fascinating object in the night sky. Being the only natural satellite of Earth and the closest celestial body, It is also a test ground for our planetary exploration technologies outside Earth.
The Chandrayaan-3 mission was launched on the 14th of July 2023 at 2:35 PM IST from SDSC SHAR(Satish Dhawan Space Centre, Sriharikota range) using ISRO’s most powerful launch vehicle LVM-3 M4 or Launch Vehicle Mark 3 previously known as GSLV Mk3, is a three staged medium lift launch vehicle developed by ISRO. LVM-3 took the spacecraft to an elliptical parking orbit of size 170*36500 kilometres. With the CY3 lander module touching the lunar ground on 23rd August 2023 6:03 PM IST, 41 days after its launch, India becomes the first country to safely land near the south pole of the moon and join the club of four countries who achieved safe landing on the Moon. The other countries include the USA, Russia(former USSR) and China.
The major aims of Chandrayaan-3 were:
- To demonstrate safe landing on Moon
- To demonstrate rovering in lunar surface
- To conduct in situ experiments
Chandrayaan-3 has two parts: a propulsion module and a lander module. Rover is situated inside the lander. The function of the propulsion module was to carry the lander and the rover inside to lunar orbit from earth bound orbit by step by step procedure. The engines in the propulsion module took short burns in the perigee(closest point to a celestial body in an elliptical orbit) to increase the size of the orbit. On 1st August CY3 was set into an orbit which intercepted the moon on his way and entered lunar orbit on 5th August. Then the spacecraft started to reduce its orbit. Later in an orbit of size 153*163 kilometres the lander module separated from the rover. After separation lander module further reduced the orbit to 25*130 kilometres. From there on 23rd August 5:44 PM the ‘Autonomous Landing Sequence(ALS)’ initiated and CY3 safely landed on the moon. Later the rover was deployed from the lander. Lunar orbit insertion and landing were two crucial steps in the mission.
It has a total of 7 scientific payloads. As a value addition, Propulsion module carry a payload named Spectro-polarimetry of HAbitable Planet Earth (SHAPE) which will study the factors that make earth habitable from a distance(lunar orbit) which is expected to support our missions to detect exoplanets in the future.
The lander carries 4 payloads:
- Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) : Instrument to study variation of ion density on lunar surface with time.
- Chandra’s Surface Thermo physical Experiment (ChaSTE) : to study the thermal properties of the moon.
- Instrument for Lunar Seismic Activity (ILSA): to study lunar seismic activity to understand the structure of lunar crust and mantle.
- Laser Retroreflector Array (LRA): A passive instrument to study dynamics of moon earth system.
The rover contains two payloads LASER Induced Breakdown Spectroscopy (LIBS) and Alpha Particle X-ray Spectrometer (APXS) which will study chemical and elemental composition of the moon. The rover will communicate only with the lander. The lander and propulsion module communicates with Indian space communication facility IDSN(Indian Deep Space Network). Chandrayaan-2 orbiter acts as a contingency link.
As per the recent updates, ISRO confirms that two out of the three objectives have been achieved while the third objective, in situ scientific experiments is underway. The 26kg six wheeled Pragyan rover rolled out of the lander few hours after the historic landing and the communication link between the lander and the Mission Operations Complex (MOX) located at the ISRO Telemetry, Tracking and Command Network (ISTRAC) was established. Later ISRO confirmed that the lander module payloads ILSA, RAMBHA and ChaSTE are turned on. Also it has been declared that, August 23, the day Chandrayaan 3 lander touched the lunar surface would now be celebrated as the National Space Day.
Image Credits: ISRO
History of Chandrayaan
The mission was first recommended by a group of scientists in 1999 at a meeting in the Indian Academy of Sciences. After the feasibility studies by ISRO in 2003 the former prime minister Atal Bihari Vajpay officially announced India’s lunar mission Chandrayaan. The word Chandrayaan is a combination of two Sanskrit words ‘Chandra’ and ‘Yaana’ meaning moon and vehicle. The first lunar mission of ISRO was launched on 22nd October 2008 with the aim of mapping the lunar surface and detecting the presence of water on the moon. M3(Moon mineralogy Mapper) on of the 11 payloads in Chandrayaan-3 confirmed the presence of water ice in the moon. Later in 2019 July 22 ISRO launched Chandrayaan 2 consisting of an orbiter, lander named Vikram and rover named Pragyaan to demonstrate safe landing and rovering. Unfortunately, the landing failed due to some technical issues. But, the orbiter is still functional and sends us scientific data. Chandrayaan-3 is a carefully built mission repetition of Chandrayaan 2, excluding the orbit, which is still functional.
Why do countries tend to explore the lunar south pole despite the difficulties?
Our moon has a very thin atmosphere. In the regions of the moon which are directly exposed to sunlight the temperature could reach more than 100 degree Celsius. Any water content present there will evaporate and will be lost into space. So any water content present in the moon can be only found in the permanently shadowed craters on the moon. Large number of these craters are located in the lunar south pole. The water in them can be a highly valued resource for future moon expeditions. That’s why on America’s return to the moon, on the Artemis mission they aim to land on the lunar south pole.
Lunar explorations are heading ahead and we expect our scientific and technological advancements will reveal more mysteries about the Moon. Good luck with that!!
You may also like to read: Scopes of Moon Exploration
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