UPSC Essentials | Weekly news express : Chandrayaan-3 Mission — Key takeaways & Points to ponder

Many more facts and analysis…

WHY IN NEWS?

The Indian Space Research Organisation (ISRO) scripted history as Chandrayaan-3 spacecraft made a soft landing on the surface of the Moon Wednesday evening. The Vikram lander made the soft landing at 6.04 PM (IST), ending the disappointment over the crash-landing of the Chandrayaan-2 lander four years ago.

KEY TAKEAWAYS

With the mission’s success, India has become the first country to land a spacecraft in uncharted territory near the lunar south pole. In fact, India is only the fourth country in history to complete a soft landing on the Moon after the United States, the Soviet Union and China.

According to ISRO, the mission’s three objectives are to demonstrate a safe and soft landing on the lunar surface, to demonstrate a Rover roving on the Moon and to conduct in-situ scientific experiments.

Soft landing simply means landing at a gentle, controlled speed to not sustain damage to a spacecraft. Amitabha Ghosh, a scientist for NASA’s Rover mission to Mars, explained it in The Indian Express thus: “Imagine a spacecraft hurtling through space, at 10 times the speed of an airplane, having to nearly come to a standstill in order to land gently on the Earth — all in a matter of a few minutes and, more importantly, without any human intervention. This, in a nutshell, is a soft landing.”

Prime Minister Narendra Modi had announced from Bengaluru that the point where the Vikram lander touched down on the lunar surface would be named “Shiv Shakti” and the crash site of the failed Chandrayaan-2 mission in 2019 as Tiranga point.

Shortly after the Vikram lander landed and its health was assessed by the space agency, the dust settled on the lunar surface and the Pragyan rover rolled out of the lander. With this, the Chandrayaan-3 mission’s 14 days of science observations has begun. ISRO chief S Somanath added that ISRO will be working on a robotic path planning exercise that could aid future exploration of the Moon.

Let’s dive deep…

Why ISRO wants to explore the Moon’s south pole?

Explained by Alind Chauhan , Amitabh Sinha

All the previous spacecraft to have landed on the Moon have landed in the equatorial region, a few degrees latitude north or south of the lunar equator. The furthest that any spacecraft has gone from the equator was Surveyor 7, launched by NASA, which made a moon landing way back on January 10, 1968. This spacecraft landed near 40 degrees south latitude.

Why do scientists want to explore the lunar south pole?

Due to their rugged environment, the polar regions of the Moon have remained unexplored. But several Orbiter missions have provided evidence that these regions could be very interesting to explore. There are indications of the presence of ice molecules in substantial amounts in the deep craters in this region — India’s 2008 Chandrayaan-1 mission indicated the presence of water on the lunar surface with the help of its two instruments onboard.

In addition, the extremely cold temperatures here mean that anything trapped in the region would remain frozen in time, without undergoing much change. The rocks and soil in Moon’s north and south poles could therefore provide clues to the early Solar System.

Why hasn’t any spacecraft ever landed near the lunar south pole?

There is a very good reason why all the landings on the Moon so far have happened in the equatorial region. Even China’s Chang’e 4, which became the first spacecraft to land on the far side of the moon — the side that does not face the earth — landed near the 45-degree latitude.

It is easier and safer to land near the equator. The terrain and temperature are more hospitable and conducive for a long and sustained operation of instruments. The surface here is even and smooth, very steep slopes are almost absent, and there are fewer hills or craters. Sunlight is present in abundance, at least on the side facing the earth, thus offering a regular supply of energy to solar-powered instruments.

The polar regions of the Moon, however, are a very different, and difficult, terrain. Many parts lie in a completely dark region where sunlight never reaches, and temperatures can go below 230 degrees Celsius. Lack of sunlight and extremely low temperatures create difficulty in the operation of instruments. In addition, there are large craters all over the place, ranging from a few centimetres in size to those extending to several thousands of kilometres.

Why don’t some parts of the lunar polar regions receive any sunlight?

Unlike the Earth, whose spin axis is tilted with respect to the plane of the Earth’s solar orbit by 23.5 degrees, the Moon’s axis tilts only 1.5 degrees. Because of this unique geometry, sunlight never shines on the floors of a number of craters near the lunar north and south poles. These areas are known as Permanently Shadowed Regions, or PSRs.

In a 2019 report, NASA said, “Water that happens to find its way into PSRs may remain there for long periods of time. Data from the Diviner instrument onboard LRO (Lunar Reconnaissance Orbiter, robotic spacecraft currently orbiting the Moon) which measures temperatures across the Moon, including PSRs, indicate that some surfaces are cold enough so that water is stable at the surface.”

Why is it so difficult to land on the Moon?

Sethu Pradeep writes:

Getting to the Moon

Long before you can even think of landing on the Moon, you will have to figure out how to get there. On an average, the Moon is about 3,84,400 kilometres away from our planet and depending on the path taken by the spacecraft, that distance can be much higher. A failure can occur anywhere on this long, long journey.

And that is true even for missions that just want to travel the Moon without landing. NASA had to terminate the Lunar Flashlight mission because a failure in the spacecraft’s propulsion system meant that it could not enter the lunar orbit.

Slowing down on the Moon

Spacecraft returning back to our planet, like NASA’s Orion after the Artemis 1 mission, can rely on the Earth’s thick atmosphere providing enough friction to slow down before touching down safely. But spacecraft entering the Moon do not have that luxury because of its extremely thin atmosphere.

In such a scenario, the only thing that can slow down a spacecraft is its propulsion system. This means that it will have to carry a lot of fuel just so that it has enough to slow itself down quickly enough to make a safe landing. But carrying more fuel means the spacecraft is heavier, requiring more fuel. This problem is a bit similar to what is known as the “Tyranny of the Rocket Equation.”

Navigating on the Moon

Needless to say, there is no GPS on the Moon. Spacecraft cannot rely on a network of satellites to precisely land at a particular location because that simply does not exist on the Moon. This means that onboard computers will have to make quick calculations and decisions to land itself precisely on the Moon.

This becomes especially complicated when a spacecraft gets within the crucial last few kilometres, according to a report in the journal, Nature . At that point, the computers on board will have to autonomously react quickly to last-minute issues. For example, sensors could become confused by the large amounts of dust kicked up by the propulsion systems.

This is made even more difficult by the fact that the Moon has an uneven surface littered with craters and boulders. Landing on either could prove catastrophic for the mission.

What went wrong with Chandrayaan-2?

Launched on July 22, 2019, the Chandrayaan-2 mission’s lander and rover were supposed to make a soft landing on the Moon on September 7. However, according to Isro Chairman S Somanath, three mistakes led to their crash on the lunar surface.

Why did the Chandrayaan-2’s lander fail to soft-land on the Moon?

Speaking to the media on Monday (June 10), Isro Chairman S Somanath pointed out three mistakes that led to the hard landing of Vikram.
“The primary issues were, one, we had five engines which were used to give the reduction of the velocity, which is called the retardation. These engines developed higher thrust than what was expected,” Somanath told the reporters, according to a PTI report. He explained that the extra thrust led to the accumulation of errors, which, in turn, compromised the stability of the lander during the “camera coasting phase’’ for the soft landing.

This is where the second problem occurred. “All the errors got accumulated, which was on the higher side than what we had expected. The craft had to make very fast turns. When it started to turn very fast, its ability to turn was limited by the software because we never expected such high rates to come,” Somanath added.

The third problem emerged when the lander, despite being close to the surface, increased its velocity as the landing site was quite far away. Somanath said this partly happened because the landing spot was quite a small patch of 500 m x 500 m.
“In a nutshell, the problem in Chandrayaan-2 was that the ability to handle parameter dispersion was very limited,” he said, according to the PTI report.

(With inputs from PTI)

What is “15 minutes of terror” ?

After Chandrayaan-2 failed in its soft landing mission, K Sivan, then chairman of ISRO, described this process as “15 minutes of terror” for them. It includes four phases:

1. The Rough Braking phase includes reducing the lander’s horizontal velocity from a range of 1.68 km/sec (more than 6,000 km/h) at a height of 30 km from the lunar surface, to almost zero for a soft landing at the designated site. This has to be done with precision, within certain durations. Read this explainer for a more detailed explanation.

2. At a height of 7.42 km from the surface, the lander is to go into an “attitude hold phase” lasting around 10 seconds, during which it should tilt from a horizontal to a vertical position while covering a distance of 3.48 km.

3. The “fine braking phase” lasts around 175 seconds, during which the lander is to move fully into a vertical position. It is to traverse the final 28.52 km to the landing site, the altitude will come down to 800-1,000 m, and it would reach a nominal speed of 0 m/sec. It was between the “attitude hold phase” and the “fine braking phase” that Chandrayaan-2 lost control and crashed.

4. “Terminal descent” is the final stage, when the spacecraft is supposed to descend totally vertically onto the surface.

What are the key upgrades in Chandrayaan-3 from 2019’s Chandrayaan-2?

Johnson T A writes:

Key upgrades in Chandrayaan 3

1.Strengthened legs

A Lander does not have wheels; it has stilts, or legs, which are supposed to touch down on the lunar surface, and then stabilise. Chandrayaan-2 lost control over its descent around 7.2 km from the surface of the Moon. Its communications system relayed data of the loss of control up to around 400 m above the surface. The Lander had slowed down to about 580 km/hr when it crashed.

The legs of Chandrayaan-3 have been strengthened to ensure that it would be able to land, and stabilise, even at a speed of 3 m/sec, or 10.8 km/hour. Of course, this would be of little use if Chandrayaan-3 is struck by a problem similar to the one that crashed Chandrayaan-2, but this can certainly avert many other kinds of troubles in case of a rough landing.

2.Bigger fuel tank

The Chandrayaan-3 Lander is carrying more fuel than Chandrayaan-2. This has been done to ensure that the Lander is able to make a last-minute change in its landing site, if it needs to.

The Chandrayaan-2 Lander too had the ability to change its course if the onboard cameras detected a boulder, a crater, or any other lunar surface feature that would make the landing unstable. The extra fuel is meant to enhance this capability.

3. Sun on all its faces

The Chandrayaan-3 Lander has solar panels on four sides, instead of only two in Chandrayaan-2. This is to ensure that the Lander continues to draw solar power, even if it lands in a wrong direction, or tumbles over. At least one or two of its sides would always be facing the Sun, and remain active.

4. More instruments

Additional navigational and guidance instruments are on board Chandrayaan-3 to continuously monitor the Lander’s speed, and make the necessary corrections. This includes an instrument called Laser Doppler Velocimeter, which will fire laser beams to the lunar surface to calculate the Lander’s speed. New sensors and cameras have also been added.

5. Updated software

The hazard detection and avoidance camera and the processing algorithm have been upgraded. The navigation and guidance software has also been updated. Multiple layers of redundancies have been added to ensure that if one system does not work because of any reason, something else will.

6. Multiple stress tests

The Lander has been subjected to multiple stress tests and experiments, including dropping it from helicopters. ISRO created several kinds of test beds at one of its facilities to simulate lunar landing conditions.

How Chandrayaan-3 may be seen in the world?

Shyam Saran in the opinion piece of The Indian Express writes that India is now at par with China and better than Russia. He explains:

“Chandrayaan-3 succeeded where a Russian lunar landing craft – Luna-25 — failed and crashed a few days earlier. It may have been a coincidence that Russia, already a seasoned space-faring nation, launched its Moon landing project virtually days after India did. But Russian failure and Indian success will be assessed side by side. Russia’s failure is already being seen as a symptom of its decline and inability, in terms of resources, to maintain its status as an advanced space power. Space exploration is a high-risk and expensive pursuit and India itself suffered disappointment when its Chandrayaan-2 also crashed on the Moon’s surface in September 2019. There is no reason to believe that Russia will not overcome this setback and pick up the pieces again. But perceptions matter. Chandrayaan-3 reinforces the international perception of India as a rising power and that of Russia as a declining power. If Russia undertook this project to counter the notion that it was no longer in the front ranks of technologically advanced countries, that the Ukraine War had not in any way dented that position, it failed. The political and psychological setback is obvious from the very limited coverage that the failed Moon mission received in the Russian media.

China has always looked down upon India as being out of its league as a global economic and technological power. It sees India as pretending to be a leading power without having the economic and technological capabilities to back it up with. India’s earlier demonstrations of scientific and technological excellence, for example, in the nuclear and space fields or in its successful IT sector, have been received with surprise. They have often been dismissed as “borrowed” from other countries. Chandrayaan-3’s outstanding achievement may be difficult to dismiss in a similar manner. Perhaps this may lead China to shed some of its arrogance and approach India as a country which must be treated with respect rather than condescension. The two countries can put their relations on an even keel only if they treat each other as equals. How China reacts to Chandrayaan-3’s success will be a pointer to whether there is a shift in China’s posture towards India after the violent clashes at the Line of Actual Control in eastern Ladakh.”

The Private Sector

Somak Raychaudhury writes for The Indian Express:

“One is painfully aware that the private sector in India, despite being capable, is engaged in only a tiny fraction of the space enterprise in the international industrial sector, currently valued at about $500 billion. This has to change, and the Indian industry must become a major global player.

The government’s newly-unveiled Space Policy 2023 states that India’s space programme should “enable, encourage and develop a flourishing commercial presence in space”. Chandrayaan-3 is a clear example of how India’s space programme is helping achieve this goal.

The mission is a joint project between ISRO and the Indian private sector. This is the first time that India has partnered with the private sector on a major space mission, and it demonstrates the government’s commitment to the new Space Policy. The lander and rover that will be deployed on the Moon were developed by a consortium of Indian companies in collaboration with ISRO laboratories. The mission’s ground control systems were also developed by ISRO with the help of the industry, and much of the mission’s data will be processed and analysed by the private sector.”

JUST FYI

India is now a signatory to the Artemis Accords, an agreement with the other leading Space Agencies of the world – NASA (US), ESA (Europe), JAXA (Japan) and the CSA (Canada) — for moon exploration with a view to colonise it. If Chandrayaan-3 can lead the way in this challenging region, future Artemis astronauts, based on ISRO’s pioneering work, will be able to collect core samples and volatiles from these regions. This could have a profound impact on the future of deep space exploration and eventual commercial activities.

India’s scientists are now taking part in a few frontline worldwide projects that are pushing technological boundaries. India has dealt with hardware and software challenges in the Thirty Meter Telescope project, in collaborations at the Large Hadron Collider at CERN, and in the preliminary stages of the recently-approved Laser Interferometric Gravitational Wave Observatory in India (LIGO-India) and the Square Kilometre Array in Radio Astronomy. The technological achievements in the astrophysics and space sectors are now for the world to see.

What else you should know?

After a successful moonshot, ISRO aims for the Sun

More immediately, however, ISRO is focussing on the early September launch of Aditya-L1, India’s first mission to study the Sun. The spacecraft will be placed in a halo orbit around the Lagrange point 1 (L1) of the Sun-Earth system, which is about 1.5 million km from the Earth.

Lagrange points are positions in space where objects sent there tend to stay put. At these points, the gravitational pull of two large masses (in this case, the Earth and the Sun) precisely equals the centripetal force required for a small object to move with them. This means, spacecraft can remain in one position without requiring too much fuel.

There are five Lagrange points where a small mass can orbit in a constant pattern with two larger masses. ISRO’s mission will join SOHO at the L1 point. Notably, the James Webb Telescope is currently positioned in a halo orbit on the L2 point.

Placing the Aditya-L1 spacecraft in a halo orbit around the L1 point of the Earth-Sun system will mean that it will be able to continuously view the sun, without any disruption. Equipped with seven payloads, it will study the Sun’s corona, solar emissions, solar winds and flares, and Coronal Mass Ejections (CMEs), and will carry out round-the-clock imaging of the star.

The L1 point is already home to the Solar and Heliospheric Observatory Satellite (SOHO), an international collaboration project of NASA and the European Space Agency (ESA).

A trip to the Evening Star

Also on the cards is a trip to Venus, hopefully within the next couple of years. “Currently a Venus mission has been conceived, a project report is made, money identified, an overall plan has been prepared … all this has been done,” Somanath said, speaking at the inauguration of a one-day meet on Venusian Science in Ahmedabad last year.

While the exact details of this mission are yet to be revealed, like previous ISRO missions, the conceived Venus mission will also emphasise on scientific research while also showcasing the space agency’s technical prowess.

Only slightly smaller than Earth, Venus was once believed to be very similar to our home planet. In fact, prior to planetary exploration, many believed that it would be suitable to human exploration. But early missions to Venus in the 1960s discovered that conditions were extremely inhospitable, making exploration an extremely challenging task.

The intense heat and crushing pressure on the planet are further aggravated by the contant volcanic activity. Till date, the longest any spacecraft has survived on the planet’s surface is a little over two hours – a record set by the Soviet Union’s Venera 13 probe in 1981.

While ISRO’s first Venus mission is likely to be a somewhat easier orbiter mission, it is yet to be seen whether the agency plans to send a spacecraft to the planet’s surface.

Sending humans to space the ‘ultimate’ aim

Perhaps ISRO’s ultimate goal in the near future is to carry out manned space missions, something that would signal a radical advancement in ISRO’s capabilities.

The Gaganyaan project envisages demonstration of human spaceflight capability by launching crew of three members to an orbit of 400 km for a three day mission, and bring them back safely to Earth, by landing in Indian sea waters.

ISRO is already working on a modified version of the LVM-3 rocket, used for Chandrayaan-3, to take humans to space. The HLVM-3 (Human-rated LVM-3) will be capable of launching an orbital module to an intended Low Earth Orbit of 400 km. It will incorporate a crucial Crew Escape System (CES).

Before Gaganyaan takes flight, however, Indian astronauts are already set to go to the International Space Station (ISS), sometime next year. Just a couple of months ago, ISRO and the United States’ NASA agreed to send a joint human spaceflight mission to the ISS. This would be the first time in 40 years that Indians would fly to space, though they would ride a NASA spacecraft and not India

That would mean that the first Indian astronauts to go in space in 40 years would ride a NASA spacecraft, not India’s own.

Point to ponder

The successful landing of Chandrayaan-3 on the moon, that happened last week, is one of the most defining moment in India’s history. Have you ever thought why?

Thought process

Chandrayaan-3 consolidates India’s position as a space power. The mission’s success will inspire generation of scientists and engineers- and all those who seek knowledge- so set the bar higher.

Compared to other powers, India has a comparatively low-budget aero-space programme. But the efficiency and cost-effectiveness with which ISRO carries out its projects have helped in building a formidable brand name for the space agency. Chandrayaan-3 was accomplished at a cost of Rs 615 crore (a fraction of the cost of an Airbus) — Russia’s Luna 25 which crashed last Sunday came with a price tag of Rs 1,600 crore and China’s shot at the Moon cost more than Rs 1,700 crore.

Also remember, the fact that India made it in the second attempt does not take anything away from the achievement. On the contrary, The Indian Express’ Editorial writes, it underlines the resiliense, commitment and character of the space agency. There is not one space faring nation that has not encountered spectacular failure.

BTW

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