Spacecraft Chandrayaan-3 Soft-Landing on Moon

India created a history in the space research and technology on the Wednesday, 23rd August 2023 (IST 18:03 Hrs), when the Indian Space Research Organization (ISRO)’s Chandrayaan-3 made a perfect soft-landing on moon’s surface with an absolute precision. This august and rare success is also remarkable from the point of view that the landing was done on the south pole region of the moon where no other country of the so-called elite space club nations, has ventured ever in the past owing to its difficult and unpredictable terrain. With this feat, India became the fourth country to achieve a successful mission to moon; the other three being the USA, Russia and China. The part of spacecraft now positioned at the surface of moon contains the Vikram Lander and Pragyan Rover modules, which are likely to remain active for one full day on moon (i.e., equal to 14 earth days). During their active phase, they are likely to look for the traces of water/ice, minerals in the moon crust, etc., and send it back to ISRO control station through orbiter encircling the moon.

The Vikram Lander has already established communication links with the Missions Operation Complex of ISRO in Bengaluru, Karnataka. The Pragyan Rover was carried inside the lander, which soon rolled out on to the moon surface as scheduled sometime past midnight. The Pragyan Rover has been so designed as to leave an imprint of the National Emblem of India and ISRO’s logo on the lunar surface wherever it goes on the moon surface. It is expected that it will roam over the rather bleak and unchartered terrain during the next few days while simultaneously sending back relevant data and visuals. Hopefully, India’s bid to unravel mysteries on the so far unexplored side of the moon shall produce useful data and information for the global benefits and awareness, as also exclaimed by an elated ISRO Chairman S. Somnath amid applause immediately after the lander touched the moon surface: We have achieved soft-landing…India is on the moon…This is the beginning of the golden era.

About the Chandrayaan Programme

The Chandrayaan is the native or indigenous name given to the Indian Lunar Exploration Program, which is currently an ongoing series of outer space missions by the Indian Space Research Organization (ISRO) for the exploration of the earth’s only natural satellite, Moon. So far, three missions to the moon have been undertaken and the current successful mission was third such attempt. Normally, apart from the launch rocket (propulsion module) with necessary fuel, such missions have four important modules, namely a lunar orbiter, an impactor, a soft lander and a rover spacecraft. Only the later two missions made serious attempt containing all modules; of which, the Chandrayaan-2 mission crashed on the moon surface at the last stage while the recent Chandrayaan-3 successfully soft-landed on the moon surface on its south polar region, thus enabling Bharat (India) to become only the fourth country in the world to have successful expedition involving landing on the moon following the US, Russia and China.

Idea about the Chandrayaan Project was conceptualized in 1999 with the former Prime Minister Atal Bihari Vajpayee himself announcing the mission. The Chandrayaan-1 was finally launched by the ISRO on 22 October 2008 from Satish Dhawan Space Centre, Sriharikota in Andhra Pradesh using a PSLV-XL rocket. The spacecraft included an orbiter and mission impact probe (MIP) largely using indigenous technology and the vehicle was successful placed in the lunar orbit on 8 November. Nearly a week later, the MIP was separated from the orbiter that hit the south pole region in a controlled manner on 14 November 2008, the location was named as Jawahar Point after the India’s first Prime Minister Jawaharlal Nehru. The orbiter was expected to function for about two years during which it would explore three-dimensional topography and mapping of the moon surface for finding its chemical composition, trace of water, etc. However, it started experiencing technical issues and stopped communication with the earth station on 28 August, 2009, with the ISRO announcing of mission’s closure after achieving its most intended objectives. Its achievement included detection of some water molecules, mapping and atmospheric profiling of the Moon.

Chandrayaan-2 was second such mission of the ISRO which was comprised of a lunar orbiter, the lander and a rover. Even before the launch of its first mission, the ISRO had signed an agreement with the Russian Space Agency Roscosmos mainly taking the latter’s assistance in developing the lander module. However, Russia later expressed its inability to provide the lander in the stipulated timeframe; hence India decided to develop its lunar mission independently, including the lander module. The chief scientific objective was to map and study the lunar surface composition and availability of water. The second launch was also done from the Satish Dhawan Space Centre on 22 July 2019 by a LVM3 rocket. The spacecraft was successfully inserted in the lunar orbit on 20 August 2019 scheduling the lander and rover to land in the south polar region on 6 September 2019. However, at the final stage, the lander crashed deviating from its trajectory during landing on the scheduled date owing to some software glitch, as revealed by the Space Agency after due analysis. The orbiter of the Chandrayaan-2 is still operational and is expected to have over seven years of life collecting scientific data for the ISRO.

Chandrayaan-3 is the current and third Indian lunar mission undertaken by the ISRO after the partial success of the previous launch. After nearly four years preparations and hard work since 2019, Chandrayaan-3 was launched on 14 July 2023 from the Satish Dhawan Space Centre (SDSC), Sriharikota using an advanced LVM3 rocket. It consisted of the orbiter, the lander Vikram and the rover Pragyan; incidentally, the names of the lander and rover from the Chandrayaan-2 have been retained. After the successful launch, the spacecraft occupied the lunar orbit on 5 August and the lander Vikram soft-landed in the south pole region on 23 August 2023 as scheduled; thus, Bharat becoming only fourth nation to achieve this feat and first nation to land in the said region. The south pole region of the moon is of particular interest for the scientific exploration supposedly owing to the mountainous terrain, uneven & unpredictable lighting conditions and a large amount of ice, making the scientific probe a challenging yet more useful task. Though far-fetched for now yet a distinct possibility in future is that the ice on the moon could be tamed as a viable source of drinking water, hydrogen for fuel and oxygen for the crewed missions.

Chandrayaan-3: Technical Features & Objective

Technically, the Chandrayaan-3 is a follow-on mission to Chandrayaan-2 with an objective to demonstrate end-to-end capability in safe landing and roving on the lunar surface. It comprises of the Lander and Rover configuration but the propulsion module is also a crucial part of the mission, which consists of the latest variant of the LVM3 rocket to be launched from SDSC, Sriharikota. The latter would carry the lander and rover configuration till nearly 100 km lunar orbit along with the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload or orbiter to study the spectral and polarimetric measurements of Earth from the lunar orbit. Thus, the mission essentially carries largely indigenous built a Propulsion Module (PM) and a Lander Module (LM) with a Rover. The main purpose of the Propulsion Module is to carry the Lander Module from launch vehicle injection till final lunar 100 km circular polar orbit and separate the PM and LM, while the latter would soft-land on the moon surface at the specified site and deploy the Rover out in-situ for the data collection and chemical analysis of the lunar surface during the course of its mobility.

The mission objectives of the Chandrayaan-3 as formally revealed by the ISRO are: 1) To demonstrate safe and soft landing on the lunar surface; 2) to demonstrate Rover roving on the moon; and 3) to conduct in-situ scientific experiments. To achieve the aforesaid objectives, the ISRO has employed relevant advanced technologies in the Lander including state of the art altimeters, velocimeters, inertial referencing and accelerometer package, propulsion system, navigation, guidance & control devices and software, hazard detection & avoidance camera and processing algorithm, and landing leg mechanism. To make sure that the aforesaid advance technology systems flawlessly work with precision, elaborate testing were carried out successfully for long in simulating conditions. The Lander module was inter alia equipped with instruments to measure the thermal conductivity, seismic activity, plasma density and its variation, lunar laser ranging studies, and so on. Similarly, the Rover module was equipped with mechanism to analyse the elemental composition in the vicinity while roving with ease in the anticipated rugged terrain.

The anticipated mission life of the Lander Vikram and Rover Pragyan is one lunar day which is equivalent to about fourteen earth days while the prescribed range of the prime landing site is an area of 4 km x 2.4 km, and they are working satisfactorily after the successful landing while the author is penning these lines. The total estimated mass of the mission was 3900 kg, of which the PM was comprised about 2148 kg while the LM 1752 kg along with the Rover about 26 kg. While the most of readers may find specifications of the units of power generation, communication, sensors, actuators, propulsion system and lander mechanism too technical to grasp with sufficient interest, mention of its lander velocities might be of some interest as millions of onlookers were tied with the Lander’s live landing on the scheduled date. Thus, the Lander touchdown specifications included a vertical velocity of approximately two meter per second while the horizontal velocity was 0.5 meter per second with near twelve-degree slope.

The chief functional objectives of various scientific payloads viz. the Lander Vikram and Rover Pragyan carried by the Chandrayaan-3 Lander on to the moon surface are enumerated below, the first five are assigned to the Lander and last two to the Rover:

1)     The radio anatomy of the moon bound hypersensitive ionosphere and atmosphere (RAMBHA);

2)     The measurement of the near surface plasma (ions and electrons) density and its changes with time, technically known as the Langmuir probe (LP);

3)     The measurements of thermal properties of lunar surface near polar region, designated as Chandra’s surface thermos-physical experiment (ChaSTE);

4)     The measurement of the seismicity around the landing site and delineating the structure of the lunar crust and mantle i.e., instrument for lunar seismic activity (ILSA);

5)     A passive experiment to understand the dynamics of the Moon system through the Laser Retroreflector Array (LRA);

6)     To carry out the qualitative and quantitative elemental analysis (chemical composition) of the lunar surface through the Laser Induced Breakdown Spectroscope (LIBS); and

7)     To determine the elemental composition of the lunar soil and rocks around the lunar landing site through the Alpha Particle X-ray Spectrometer (APXS).

In addition, the propulsion module payload (orbiter) is likely to assist in discovery of smaller planets in reflected light accelerating future probe into variety of Exo-planets from the prospective of the presence of life.

Significant & Landmark Events in Moon Landing

By the end of first week of July 2023, the ISRO had completed necessary tests, scheduled the launch of Chandrayaan-3 for the 14th July and extended open invitation to citizens to watch it from the Launch View Gallery at the SDSC, Sriharikota at the scheduled date and time.

During 11 to July 14, the launch rehearsal simulation exercise was carried out and the LVM3 (M4 version) vehicle successfully launched Chandrayaan-3 into the earth orbit commencing its voyage to the moon.

Between 15 to 25 July, the progress of the Chandrayaan-3 was constantly watched and five successive orbit-raising manoeuvres were successfully carried out on various dates, scheduling the trans-lunar injection for the 1st August 2023 after the fifth such manoeuvre on 25 July.

Through the successful manoeuvres and absolute precision, the Chandrayaan-3 was inserted in the translunar and lunar orbits on 1st and 5th August respectively. During the next three days, the spacecraft’s orbit was reduced to 174 km (maximum distance) and 1437 km (orbit length) on 9 August. Then the spacecraft was put into an orbit of 153 km x 163 km through a successful firing and manoeuvre on 16 August 2023.

The milestone event on 17 August included successful separation of the Lander Vikram from the propulsion module. The spacecraft was put in the 25 x 134 km orbit on 20 August through precision manoeuvre, scheduling the powered descent and soft-landing process of the Lander to commence around 1745 Hrs IST on 23 August.

The spacecraft (Lander Vikram) successfully soft-landed on the moon surface on 23 August 2023 precisely at 1803 Hrs under in full view of the enthusiastic and keen eyes of the millions of Indians and other people across the world. The Lander immediately flashed the message back through the orbiter to the earth station “I reached my destination and you too!”

The Rover Pragyan, housed so far within the lander module, soon ramped down from the Lander in the early hours of 24 August 2023 taking a slow and measured walk on the moon.

Aftermath of Chandrayaan-3: Reactions & Responses

Some of the authentic technical data and information later received and released by the ISRO after the landing of the spacecraft on the moon surface include the Pragyan movement around the landing site (through ILSA), measured near surface plasma content (RAMBHA-LP on board), detection of some trace elements (courtesy APXS) and conclusive proof of the presence of sulphur on the lunar surface (courtesy LIBS). Apart from sulphur, traces of aluminium, calcium, iron, chromium and titanium have also been unveiled on the lunar surface. Later the ISRO also added that further measurements and analysis have suggested the presence of manganese, silicon and oxygen too while the investigation for the presence of hydrogen is underway.

Within the country, the jubilant media, countrymen and political ruling class witnessed the event and were all praise for the ISRO, scientific community and government for achieving this rare feat. However, among the opposition political parties, the leaders generally appreciated the achievement and ISRO scientists. Some Congress leaders simultaneously gave credit to the former Congress prime ministers Jawaharlal Nehru and Indira Gandhi for their vision and support to the space programme and one senior party leader Digvijay Singh even created a controversy with (unsubstantiated) allegations that the scientists involved in the Chandrayaan Mission were not paid their salaries for the last seventeen months.

On the other hand, a vast global support and appreciation has been received from the international community, including media, for this distinction and remarkable feat of scaling the so far unexplored side of the moon owing to its difficult conditions and terrain. Official response and felicitations from India's neighbour such as Nepal, Bhutan, Sri Lanka and Maldives were immediately received as also from some other fellow Asian countries India on its successful lunar mission and Chandrayaan-3 landing on the moon. However, the Chinese and Pakistani governments did not respond, and it was on 25 August that Pakistani foreign affairs spokesperson acknowledged the achievement.

The US Department of State, NASA and several distinguished Americans individually acknowledged ISRO’s Chandrayaan-3 successful moon landing. The director general of the European Space Agency (ESA) described the spacecraft’s soft landing as ‘incredible’ achievement. Similar felicitations were received from the British High Commission and some members of the British Parliament. The Russian President personally congratulated the President and Prime Minister of India on the successful mission. The Kremlin website further added, “This is a big step forward in space exploration and, of course, a testament to India's impressive progress in science and technology…”

This section will remain incomplete if the reaction and coverage of the international media is not touched upon. The Western and Arab world media is generally known for their age long bias against India and its majority population comprising of Hindus. This bias has further grown after the government at Centre was formed under the nationalist leader Narendra Modi in 2014 and it is seldom that one would find an objective or unbiased reporting on India, Hindus and Mr. Modi from the mainstream media agencies like the New York Times, Washington Post, the Guardian, the BBC, Al Jazeera, and many more.

It was in 2014, when the ISRO achieved a rare feat of successfully inserting its first interplanetary mission orbiter, the Mangalyaan probe, into the orbit of Mars on 24 September and thus becoming only fourth space agency after the NASA, Roscosmos and ESA to accomplish this task, the New York Times viciously ridiculed India by publishing a cartoon on 28 September that showed rather a rustic farmer with a cow knocking at the door of a cabin marked the "Elite Space Club" with two elites reading a newspaper on India's success. Of course, the NYT had routinely expressed regret later on for this outlandish approach smelling the racial bias.

Now almost nine years later, the recent achievement of India's Chandrayaan-3 mission has received a different coverage and treatment from the global media. The majority of media houses have lauded India and ISRO for achieving the rare feat of successfully spacecraft landing on the south pole region of the moon. The NYT’s headline this time read, “In Latest Moon Race, India Lands First in Southern Polar Region"; then the story also inter alia described that the Indian people take great pride in the nation’s accomplishments of the space programme that orbited the Moon and Mars and routinely launched satellites above the earth with far fewer financial resources than other nations. It further added that the achievement of the Chandrayaan-3 would be far sweeter.

Similarly, during the recent years on more important issues like Ram Janmbhumi dispute, Article 370 on Kashmir, anti-CAA protests, Delhi riots of 2020, Farmers’ agitation or even Covid-19 outbreak, Western media such as the BBC, Washington Post, the Guardian, Al Jazeera, etc., have frequently resorted to a lopsided, and often misleading, reporting but, to utter surprise or may be for a change, a reasonably fair and more objective reporting has been done in this case. For instance, the BBC headline covering the feat of Chandrayaan-3 carried the headline, “India makes history as Chandrayaan-3 lands near Moon's South Pole". In the main texts also, it sounds better…This is a massive moment for India – and it bumps them up the space superpower list, citing the Russia’s currently failed attempt to justify how arduous is the task.

The Washington Post headline read, “India lands a spacecraft softly on the moon's surface", then the story narrated how the successful soft-landing of the Chandrayaan-3 mission was a great triumph for the country with growing ambitions in the space and how the success was celebrated by the nation comprising of over one billion people. The UK based daily the Guardian wrote under the headline, "India lands spacecraft near the south pole of moon in historic first". The story inside referred to India’s emergence as a space power and the government’s stress on investment in private spaces launches and related satellite based commercial activities. Qatar based and state-owned Arabic-language international news network, Al Jazeera as the major representative of the Arab world is so often critical of India, its government and majority Hindu community. However, on the Chandrayaan-3’s moon landing, it’s headline read, "India moon landing live news: Chandrayaan-3 makes space history", and further added that India successfully landed the spacecraft near the moon's south pole, making it the first country to do so.

End Note

Needless to mention, the Indian pursuit of the space exploration by its dedicated agency ISRO has indeed achieved a remarkable milestone after the successful execution of the Chandrayaan-3 Mission having reached and soft-landed on the lunar surface of its south pole region, which is considered to be a tough task so far not achieved by any of the other successful countries of the so-called elite space club. This attainment has marked a noteworthy step towards the contributions of the Indian science, technology, engineering and industry in the national build up in terms of its development and progress at the beginning of the current millennium. Let there be no doubt that the success of the Indian moon mission will trigger global interest too in lunar exploration and take the space mission to even more higher-level consolidating India’s overall position in the world. The ISRO is likely to undertake more ambitious moon and inter-planetary missions in the future, one such mission to the sun is already scheduled on 2nd September 2023.

Apart from the scientific and technological significance of the Chandrayaan-3 feat, such successes and achievements at the national level also help to generate and inculcate a collective sense of pride and oneness among the countrymen, besides inculcating a general awareness and keenness to build an ecology with scientific temperament and innovation. Here the author would also like to record the significant contrast in the priority and approach of the previous Congress governments and the present government under the dynamic leadership of Mr. Narendra Modi. During the earlier Congress government, the point where the MIP hit on the moon surface was named as the Jawahar Point after the name of former Congress Prime Minister Jawaharlal Nehru while the subsequent both landing sites viz. where the lander of Chandrayaan-2 was scheduled to touch down and where the lander of Chandrayaan-3 actually soft-landed, have been named as ‘Tiranga’ and ‘Shiv Shakti’ respectively. The first one is of national significance while the second symbolizes collective strength of women contributing to the mission.

Note: ISRO website has been consulted for data and information

Images (c)


More by :  Dr. Jaipal Singh

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