Chandrayaan (India’s moon mission)

From Indpaedia
(Difference between revisions)
Jump to: navigation, search
(Why does India/ the world want moon missions?)
(Chandrayaan 2)
Line 209: Line 209:
  
 
''Chandrayaan 2: The planned path''
 
''Chandrayaan 2: The planned path''
 +
 +
===How will Chandrayaan II study the moon?===
 +
[https://www.thehindu.com/sci-tech/science/how-will-chandrayaan-2-study-the-moon/article28422645.ece  Shubashree Desikan, How will Chandrayaan 2 study the moon?, July 13, 2019: ''The Hindu'']
 +
 +
[[File: Chandrayaan II- Some details.jpg|Chandrayaan II- Some details <br/> From: [https://www.thehindu.com/sci-tech/science/how-will-chandrayaan-2-study-the-moon/article28422645.ece  Shubashree Desikan, How will Chandrayaan 2 study the moon?, July 13, 2019: ''The Hindu'']|frame|500px]]
 +
 +
 +
''Why is India’s first attempt at a powered lunar landing important?''
 +
 +
The story so far: When Chandrayaan 1, India’s first moon mission was launched on October 22, 2008, from Sriharikota, using the Polar Satellite Launch Vehicle (PSLV), India became the fourth country to plant its flag on the lunar surface. On the moon, the mission conclusively detected traces of water along with magnesium, aluminium and silicon. Now, close to a decade later, India will launch its second lunar mission, Chandrayaan 2, on July 15, 2019, again from Sriharikota, using the Geosynchronous Satellite Launch Vehicle (GSLV) Mark III rocket. The launch falls a day short of the 50th anniversary of the launch of the American mission Apollo 11 which took humans to the moon and back. The first moon landing occurred on July 20, 1969, on the Apollo 11 mission which was launched on July 16.
 +
 +
 +
'''How will the launch work?'''
 +
 +
The GSLV Mark III rocket will first launch the spacecraft into an Earth Parking Orbit (170 km X 40,400 km). Then the height of the orbit will be enhanced until the spacecraft can reach out to the Lunar Transfer Trajectory. On entering the moon’s sphere of influence, on-board thrusters will slow down the spacecraft, allowing it to be captured by the moon. Then it will be eased into a circular orbit (100 km X 100 km). From this orbit, the lander and rover will separate as a unit from the orbiter, and, through a series of braking mechanisms, the duo will “soft-land” on the moon, on September 6, 2019.
 +
 +
 +
'''What is special about Chandrayaan 2?'''
 +
 +
Chandrayaan 2 will be the first mission to reach and study the south pole of the moon. It is made up of an orbiter, a lander named ‘Vikram’, after Vikram A. Sarabhai, the founding father of space science research in India, and a rover named ‘Pragyan’, which means ‘wisdom’. At about 3,877 kg, the spacecraft weighs nearly four times its predecessor, Chandrayaan 1. It will be launched by the GSLV Mark III, the Indian Space Research Organisation’s (ISRO’s) most powerful and massive launcher. While Chandrayaan 1 sent its lander crashing into the moon, Chandrayaan 2 will use rocket technology to soft land ‘Vikram’, carrying its ‘Pragyan’ rover in a suitable high plain on the lunar surface, between two craters, Manzinus-C and Simpelius N, at a latitude of about 70º South. This landing is scheduled for September 6 this year. The total cost of the project is about ₹978 crore. The lander-rover combo has an expected lifetime of 14 days, while the orbiter will continue for a year.
 +
 +
 +
''' ''How will Chandrayaan 2 study the moon?'' '''
 +
 +
'''How does the ‘Pragyan’ rover operate and what determines its lifetime?'''
 +
 +
The time taken for the moon to complete one rotation on its axis is approximately equal to 29.5 earth days. This is also equal to the time it takes to complete one orbit around the earth. That is why the same side always faces the earth. But because it takes 29.5 earth days to complete one rotation, every point on its surface experiences daylight for about half the time, or a little more than 14 days at a stretch. Moon days are nearly 14 earth days long. Note that the landing is scheduled for September 6, when we will see the first quarter of the moon. This is a date when the lander will land at a point that is facing the earth and which has started receiving sunlight.
 +
 +
This point will receive light for nearly another fortnight which will match the expected lifetime of the lander-rover combo. Since the ‘Vikram’ lander and ‘Pragyan’ rover are powered by solar energy, they will be energised during this period by sunlight on the moon. Once night falls, this energy will not be available as they are plunged into a dark and cold -180º Celsius environment. If the lander-rover duo should kickstart after another half-rotation when day breaks once again, it will be a bonus for the ISRO.
 +
 +
The mission is not designed to survive this extreme cold, unlike some U.S. and Chinese missions which survived on the “dark” side of the moon using special sources of warmth.
 +
 +
 +
'''How will the mission study the moon?'''
 +
 +
Using the Terrain Mapping Camera 2 which is on board the orbiter, the mission will produce images of the moon remotely from a 100 km lunar polar orbit. While the moon rotates about its axis, along its east-west direction, say, the lunar polar orbit will be in the perpendicular direction, along the lunar north-south direction. Thus, as the moon rotates, the orbiter gets a view of its entire surface from overhead. This data collected by the orbiter will be used to produce a 3D image of the moon’s terrain. This is just one of the eight instruments, or payloads, on board the orbiter. The lander carries three such payloads, some of which will measure the electron density and temperature near the lunar surface; the vertical temperature gradient, and seismicity around the landing site.
 +
 +
The rover will carry two instruments or payloads which will collect and test samples from the moon’s surface to identify what elements they contain. The rover moves on six wheels and once let down on the moon, can travel about 500 m from the lander.
 +
 +
 +
'''What is the success rate of “soft-landing” on the moon?'''
 +
 +
There have been 38 attempts so far at “soft-landing” on the moon, with a success rate of 52% according to the ISRO website.
 +
 +
 +
'''Why should we have this mission? Why should we study the moon?'''
 +
 +
The moon offers a pristine environment to study. It is also closer than other celestial bodies. Understanding how it formed and evolved can help us better understand the solar system and even earth itself. With space travel taking shape and exoplanets being discovered everyday, learning more about earth’s celestial neighbour can help in advanced missions. Finally, it is a piece of the larger puzzle as to how the solar system and its planets have evolved.
  
 
=Costs=
 
=Costs=

Revision as of 06:05, 14 July 2019

This is a collection of articles archived for the excellence of their content.
Additional information may please be sent as messages to the Facebook
community, Indpaedia.com. All information used will be gratefully
acknowledged in your name.

Contents

Why does India/ the world want moon missions?

The rationale

Surendra Singh, Why the world keeps returning to Chandamama, July 2, 2019: The Times of India


July 16, the day after India’s Chandrayaan-2 lifts off from Sriharikota, marks the 50th year of the launch of Nasa’s Apollo-11, the mission that took US astronauts Neil Armstrong and Buzz Aldrin to Moon. Half a century later, why Chandrayaan-2? Are we reinventing the wheel?

Similar questions were raised before Chandrayaan-1 mission (which involved only an orbiter) in 2008. But India’s first Moon mission silenced critics when it found evidence of water ice on lunar surface. The mission cost India Rs 386cr — a fraction of what the US and the USSR had spent on similar missions. Chandrayaan-2, involving an orbiter, a lander and a rover this time, will expand the ambit of India’s first lunar probe and perhaps have some surprise finds.

The first object from Earth to kiss Moon was USSR’s Luna-2 craft, on Sept 14, 1959. Under the Luna programme, USSR sent a series of robotic craft missions to Moon between 1959 and 1976, which cost $4.5 billion.

Joining the Moon race, US started the Apollo programme and 10 years later, Armstrong and Aldrin became the first humans to step on Moon, on July 20, 1969. From 1968 to 1972, Nasa launched 11 spaceflights to the Moon and a total of 12 astronauts walked on Moon. The missions cost the $25 billion, considered to be the most expensive lunar programme.

A GSLV-MIII carrying Chandrayaan-2 will lift off on July 15, and its lunar-rover module, which will cover a distance of 384,400km to reach the lunar orbit, is expected to land on the south pole of Moon, which remains virtually unexplored.

The pioneers are also getting back to the game. Fifty years after the Moon race during the Cold War era, the US and Russia have revived their Moon programmes. China and Israel, too, have the jumped on the lunar bandwagon.

In May this year, Nasa awarded $253 million to three US firms to develop robotic landers that will carry payloads to Moon as a prelude to its Artemis programme to return astronauts to Moon by 2024. Russia also plans to land cosmonauts on Moon by 2030. In January this year, China’s Chang’e-4 probe made a historic landing on the far (dark) side of Moon that always faces away from Earth and has a rugged terrain with several impact craters. After Chang’e-4 success, China announced plans to follow up with three more missions, laying the groundwork for a lunar base.

In February 2019, Israel launched its first lunar mission ‘Beresheet’ with the help of SpaceX launcher Falcon 9. Though the module, a joint venture of startup SpaceIL and state-run space agency, successfully reached the lunar orbit, it crashed on Moon. A determined Israel has now started working on Beresheet 2.0 programme.

Private players, too, are eyeing Earth’s natural satellite. The Elon Musk-led SpaceX has unveiled plans for a spacecraft that would allow the company to build a base on Moon and colonise Mars. Jeff Bezosowned Blue Origin is working on a spacecraft (Blue Moon) that will be used to transport scientific equipment and humans to Moon by 2024. For mankind, the love for Moon or Chandamama never wanes.

The road to the Chandrayaan mission

Chethan Kumar, July 4, 2019: The Times of India

1969-75- The growth of ISRO
From: Chethan Kumar, July 4, 2019: The Times of India
1977-1993: India’s satellite missions
From: Chethan Kumar, July 4, 2019: The Times of India
2008-2019: The evolution of the Chandrayaan mission
From: Chethan Kumar, July 4, 2019: The Times of India


After centuries of romanticising the Moon, mankind has been dreaming of colonising it. As our search for habitable planets still revolves around Mars, however, more space scientists are looking at Earth’s natural satellite as a layover point or a launchpad to farther expeditions. India, which will launch its second lunar mission (Chandrayaan-2) on July 15, has been conducting research on various aspects of Moon, including building habitats there. We are interested in sending people to the Moon, Isro chairman K Sivan had said.

Among some serious work by the US, Europe and China is one on using local material to build structures on Moon and building bigger rockets to transport instruments and people. Nasa is leading most of these efforts, with 2028 as the target year, while the European Space Agency is burning the midnight oil on Moon projects.

M Annadurai, the man behind Chandrayaan-1, earlier told TOI: “There’s serious thinking to use Moon as an outpost, just like missions in Antarctica. In the longrun, the space station is likely to be scrapped, and countries including the US are seriously considering building structures more permanent on Moon and working out of there. When it happens, we want India to have contributed.”

Isro has been thinking of building “igloos” on Moon. Earlier this year, Nasa administrator Jim Bridenstine said: “We’ll go to Moon in the next decade. When we go, we will stay. We’ll use what we learn as we move forward to Moon to take the next giant leap – sending astronauts to Mars.”

Senior space scientist P S Goel, however, is not so optimistic about such ventures in the near future. “Colonising Moon is slightly far-fetched as of now. But, using it as a transit point seems more realistic in the next five to ten decades. There are several engineering challengeslike how to generate energy for one—that must be overcome,” he told TOI.

China, which has soft-landed on Moon’s ‘dark side’, has been making significant strides. Scientists agree that humans on future lunar missions will be spending way more time than any of the Apollo missions (US has had 12 of them) did. But a lot of work is yet to be done to accommodate humans there, and this will be done in collaboration with serious space-faring nations combined with big private players like SpaceX.

A senior scientist advising Isro said that in the next few decades, Moon will see a lot of action, but, given the cost, countries cannot do it alone. “It has to be a collaboration, and India can earn a seat at the high table with Chandrayaan-2. You’ll also see big private participation,” he said.

Research and development

How to land on the moon

U Tejonmayam, A decade of research and development has gone into India’s lunar landing, July 10, 2019: The Times of India


For India’s second date with the Moon, expected in the first week of September, Isro scientists have swiped left and right through 3,500 images in search of the right place for the rendezvous near the lunar south pole.

Here, they hope to find clues to the origin and early history of not just the Moon, but Earth and some other members of the solar system as well. Also expected is more evidence of water.

Scientists studied data from Nasa’s Lunar Reconnaissance Orbiter and Japan’s Kaguya Lunar Orbiter to stitch together mosaics and study craters, boulders and slopes. Images of the lunar surface captured by instruments aboard Chandrayaan-1 including terrain mapping camera, hyperspectral imager, lunar laser ranging instrument, moon mineralogy mapper and synthetic aperture radar also came in handy.

“Chandrayaan-1 mapped the entire moon when the orbiter went around for nine months,” said Mylsamy Annadurai, who was the project director of Chandrayaan-1. The orbiter high resolution camera (OHRC) onboard Chandrayaan-2 orbiter will again study the landing site to detect hazards like boulders up to 32cm.

In a paper presented at the 49th Lunar and Planetary Science Conference 2018, Isro scientists said two potential sites were identified— a primary site between the two craters Manzinus and Simpelius, located 350km north of the south pole Aitken basin rim and a second site nearby.

China was the first country to land on the far side of the moon, on a crater about 180km from south pole Aitken basin. “As solar energy powers the system, a place with good visibility and area of communication was needed. Also, the place should not have many boulders or craters. The slope for landing should be less than 12 degrees. The south pole has a near-flat surface, with good visibility and sunlight,” said Isro chairman K Sivan.

The lunar south pole is especially interesting because a larger section of its surface stays in the shadow, which means a higher probability of finding water. The region also has craters that are ‘cold traps’ containing fossilised records of the early solar system, Isro said in a web post.

Accuracy is the key. “We are travelling about 3,84,000km from Earth. Even if we have an error of 1km on the landing site, all these factors should hold good,” Annadurai said. A study by Physical Research Laboratory on the topography of the landing ellipse revealed that 23,605 craters are present, including 12,600 craters with a diameter greater than 10m and 11 craters with greater than 500m diameter. The landing ellipse is generally flat with the primary landing site devoid of craters with significant depth.

Vikram has to soft-land without causing much disturbance. Lunar dust can stick to the instruments, affecting deployment of solar panel, sensors and navigational aids. The less the hovering time, the less the disturbance, said PRL scientists.

Chandrayaan 1

See graphic:

Decision making process of Chandrayaan- I

'Lost' in 2009; NASA finds it orbiting Moon in 2017

Srinivas Laxman, Chandrayaan-1 found by Nasa after 8 years, March 11, 2017: The Times of India


Eight years after it was considered “lost“, India's first lunar spacecraft, Chandrayaan-1, has been “re-discovered“ by Nasa's ground-based radars, the American space agency announced.

Chandrayaan-1, launched on October 22, 2008, was credited with the first discovery of water on the moon on November 14. After that, it suddenly lost communication with Isro ground stations on August 29, 2009 due to a technical problem. Speculation was rife at Isro then that it had crashed on the moon.

But nine years since its launch, a new radar technology pioneered by scientists at Nasa's Jet Propulsion Laboratory (JPL) was put into place to trace Nasa's Lunar Reconnaissance Orbiter and Chandraya an-1. “This technique could assist planners of future moon missions,“ Nasa said.

JPL's orbital calculations indicated that Chandrayaan-1 was still circling 200km above the lunar surface. The father of India's moon mission, Krishnaswamy Kasturirangan, told TOI, “To be declared lost and then found after eight years is a great accomplishment.“ Chandrayaan-1 was our first interplanetary mission, and I am delighted that it has been found,“ Kasturirangan said.

According to Nasa, the main challenge in detecting Chandrayaan-1 was on account of its size; the spacecraft is very small, a cube of about 1.5 metres on each side -about half the size of a smart car. It has not been transmitting signals.

According to Nasa, to find the spacecraft 3.80 lakh km away , the Jet Propulsion Laboratory (JPL) team used its 70-metre antenna at the Goldstone Deep Space Communications Complex in California.

A powerful beam of microwaves was directed towards the moon. The radar echoes then bounced back from the lunar orbit, which were received by the 100-metre Green Bank telescope in West Virginia in the US, Nasa said.

The radar team utilised the fact that Chandrayaan-1 is in polar orbit around the moon. So, it would always cross above the lunar poles on each orbit. On July 2, 2016, the team pointed Goldstone and Green Bank at a location 160km above the moon's north pole and waited to see if Chan drayaan-1 crossed the radar beam. Chandrayaan-1 was predicted to complete one orbit around the moon every two hours and eight minutes. Nasa said that the timing of the detections matched the time it would take for Chandrayaan-1 to complete one orbit and return to the same position above the moon's pole.

Help in creation of first global map of water in Moon's soil

India's Chandrayaan-1 helps scientists map water on Moon, Sep 14, 2017: The Times of India


HIGHLIGHTS

The water concentration reaches a maximum average of around 500 to 750 parts per million in the higher latitudes

NASA's Moon Mineralogy Mapper flew aboard India's Chandrayaan-1 spacecraft

Although the bulk of the water mapped in this study could be attributed to solar wind, there were exceptions

NEW YORK: Using newly-calibrated data taken from NASA's Moon Mineralogy Mapper, which flew aboard India's Chandrayaan-1 spacecraft, scientists have created the first global map of water in the Moon's soil.

The study, published in the journal Science Advances, builds on the initial discovery in 2009 of water and a related molecule - hydroxyl, which consists of one atom each of hydrogen and oxygen - in lunar soil.

"The signature of water is present nearly everywhere on the lunar surface, not limited to the polar regions as previously reported," said the study's lead author Shuai Li, who performed the work while a PhD student at Brown University in Providence, Rhode Island, US.

"The amount of water increases toward the poles and does not show significant difference among distinct compositional terrains," Li, now a postdoctoral researcher at University of Hawaii, added.

The water concentration reaches a maximum average of around 500 to 750 parts per million in the higher latitudes. That is not a lot - less than is found in the sands of Earth's driest deserts - but it is also not nothing.

"This is a roadmap to where water exists on the surface of the Moon," study co-author Ralph Milliken, Associate Professor at Brown University said.

"Now that we have these quantitative maps showing where the water is and in what amounts, we can start thinking about whether or not it could be worthwhile to extract, either as drinking water for astronauts or to produce fuel," Milliken said.

The way the water is distributed across the Moon gives clues about its source, the researchers said. The distribution is largely uniform rather than splotchy, with concentrations gradually decreasing toward the equator, the study said. That pattern is consistent with implantation via solar wind - the constant bombardment of protons from the Sun, which can form hydroxyl and molecular water once emplaced.

Although the bulk of the water mapped in this study could be attributed to solar wind, there were exceptions. For example, the researchers found higher-than-average concentrations of water in lunar volcanic deposits near the Moon's equator, where background water in the soil is scarce.

Rather than coming from solar wind, the water in those localised deposits likely comes from deep within the Moon's mantle and erupted to the surface in lunar magma. The study also found that the concentration of water changes over the course of the lunar day at latitudes lower than 60 degrees, going from wetter in the early morning and evening to nearly bone dry around lunar noon.

The fluctuation can be as much as 200 parts per million. As useful as the new maps may be, they still leave plenty of unanswered questions about lunar water. The Moon Mineralogy Mapper, which supplied the data for the research, measures light reflected off of the lunar surface. That means that it can't look for water in places that are permanently shadowed from the sun's rays.

Many scientists think these permanently shadowed regions, such as the floors on impact craters in the Moon's polar regions, could hold large deposits or water ice. "Those ice deposits may indeed be there, but because they are in shadowed areas it's not something we can easily confirm using these data," Milliken said.

Nasa probe finds water distributed across lunar surface

Srinivas Laxman, Water distributed across lunar surface: Nasa probe on Chandrayaan-1, February 26, 2018: The Times of India


An analysis of data from India’s first mission to the moon, Chandrayaan-1, and Nasa’s Lunar Reconnaissance Orbiter (LRO) has found evidence that the moon’s water is distributed across the lunar surface and not confined to a particular region or type of terrain as stated earlier.

The water appears to be present day and night, though it’s not necessarily easily accessible, said Nasa in a statement. The space agency added that they derived the conclusion after obtaining data from a diviner instrument on the LRO. Nasa has stated that the new data was obtained from the diviner instrument on LRO. “The team applied this temperature model to data gathered earlier by the moon mineralogy mapper, a visible and infrared spectrometer that NASA’s Jet Propulsion Laboratory in Pasadena, California, provided for India’s Chandrayaan-1 orbiter,” it has stated.

“The findings could help researchers understand the origin of the moon’s water and how easy it would be to use as a resource. If the moon has enough water, and if it’s reasonably convenient to access, future explorers might be able to use it as drinking water or convert it into hydrogen and oxygen for rocket fuel or oxygen to breathe,” reads the statement.

The results contradict some earlier studies, which had suggested that more water was detected at the moon’s polar latitudes and that the strength of the water signal waxes and wanes according to the lunar day (29.5 Earth days). “We find that it doesn’t matter what time of the day or which latitude we look at, the signal indicating water always seems to be present,” said Joshua Bandfield, a senior research scientist with the Space Science Institute in Boulder, Colorado, and lead author of the new study published in Nature GeoScience.

Chandrayaan-1 device finds ice on moon surface

Chandrayaan-1 device found ice on moon surface: Nasa, August 22, 2018: The Times of India


Scientists have confirmed the presence of frozen water deposits in the darkest and coldest parts of the moon’s polar regions using data from the Chandrayaan-1 spacecraft, which was launched by India 10 years ago, Nasa said on Tuesday.

With enough ice within the top few millimetres of the surface, water would possibly be accessible as a resource for future expeditions to explore and even stay on the moon, and potentially easier to access than water detected beneath the surface. The ice deposits are patchily distributed and could be ancient, according to a study published in the journal PNAS.

The scientists used data from Nasa’s moon mineralogy mapper, an instrument carried on Chandrayaan-1, to identify three specific signatures that definitively prove the presence of ice. Learning more about it will be a key focus for Nasa and its commercial partners.

Chandrayaan 2

History

Chethan Kumar, India’s tryst with Moon: 10 years and two missions, October 21, 2018: The Times of India


At 6.22am on October 22, 2008, the PSLV carrying Chandrayaan-1 roared into the sky paving the way for the future of India’s endeavours for planetary exploration. And, on November 8 that year, Chandrayaan-1 reached the polar orbit around the Moon.

M Annadurai, called the Moon-man of India recollects: “On November 14, in the presence of then Indian President APJ Abdul Kalam, we commanded a tiny Moon Impact Probe (MIP) to detach from the mother craft targeting to touch down the moon after 27 minutes of flight into the atmosphere of the moon. While climbing down to the lunar surface one of the science equipment onboard the MIP, namely CHACE— a mass spectrometer—started indicating the presence of water (vapour) in the moon’s atmosphere.”

The signal then got more pronounced when the probe was going nearer to moon’s surface. The presence of water near moon was considered to be sourced from the lunar surface. So remaining instruments on board Chandrayaan-1 mother craft were programmed to look for presence of water on the Lunar surface. Untitled design (96)

The search was for the entire surface of the moon. Accordingly Chandrayaan-1 paved the way for deriving Lunar Map with water resources (see pic). “Discovery of ice on the poles of the moon is also credited to the Chandrayaan-1. When another set of International Scientists used Chandrayaan-1 data for their research again the claim was once again got confirmed,” Annadurai said.

Chandrayaan-1 received three international awards , one each for Discovery of water on the moon, Spacecraft Design and compact accommodation of 11 Science instruments and the very high level of international co-operation that paved the way for new wave in planetary exploration.

2019: The mission

Chethan Kumar, Chandrayaan-2 nearly ready for July launch, June 11, 2019: The Times of India

See graphic:

7 challenges of the Moon landing


Isro has entered the last leg of testing of Chandrayaan-2 with integration nearly complete. Final tests are happening at Mahendragiri in Tamil Nadu and Byalalu in Bengaluru. The agency is looking at a July 9 launch. As part of Isro’s present schedule, spacecraft will leave Bengaluru on June 19, and reach the launchpad in Sriharikota on June 20 or 21. From 3D mapping to finding water molecules, and from checking out minerals to landing where nobody has landed, scientists say Isro has prepared to land a “dream on the Moon”.

2019: The planned path

Chandrayaan 2: The planned path
From: June 13, 2019: The Times of India


See graphic:

Chandrayaan 2: The planned path

How will Chandrayaan II study the moon?

Shubashree Desikan, How will Chandrayaan 2 study the moon?, July 13, 2019: The Hindu


Why is India’s first attempt at a powered lunar landing important?

The story so far: When Chandrayaan 1, India’s first moon mission was launched on October 22, 2008, from Sriharikota, using the Polar Satellite Launch Vehicle (PSLV), India became the fourth country to plant its flag on the lunar surface. On the moon, the mission conclusively detected traces of water along with magnesium, aluminium and silicon. Now, close to a decade later, India will launch its second lunar mission, Chandrayaan 2, on July 15, 2019, again from Sriharikota, using the Geosynchronous Satellite Launch Vehicle (GSLV) Mark III rocket. The launch falls a day short of the 50th anniversary of the launch of the American mission Apollo 11 which took humans to the moon and back. The first moon landing occurred on July 20, 1969, on the Apollo 11 mission which was launched on July 16.


How will the launch work?

The GSLV Mark III rocket will first launch the spacecraft into an Earth Parking Orbit (170 km X 40,400 km). Then the height of the orbit will be enhanced until the spacecraft can reach out to the Lunar Transfer Trajectory. On entering the moon’s sphere of influence, on-board thrusters will slow down the spacecraft, allowing it to be captured by the moon. Then it will be eased into a circular orbit (100 km X 100 km). From this orbit, the lander and rover will separate as a unit from the orbiter, and, through a series of braking mechanisms, the duo will “soft-land” on the moon, on September 6, 2019.


What is special about Chandrayaan 2?

Chandrayaan 2 will be the first mission to reach and study the south pole of the moon. It is made up of an orbiter, a lander named ‘Vikram’, after Vikram A. Sarabhai, the founding father of space science research in India, and a rover named ‘Pragyan’, which means ‘wisdom’. At about 3,877 kg, the spacecraft weighs nearly four times its predecessor, Chandrayaan 1. It will be launched by the GSLV Mark III, the Indian Space Research Organisation’s (ISRO’s) most powerful and massive launcher. While Chandrayaan 1 sent its lander crashing into the moon, Chandrayaan 2 will use rocket technology to soft land ‘Vikram’, carrying its ‘Pragyan’ rover in a suitable high plain on the lunar surface, between two craters, Manzinus-C and Simpelius N, at a latitude of about 70º South. This landing is scheduled for September 6 this year. The total cost of the project is about ₹978 crore. The lander-rover combo has an expected lifetime of 14 days, while the orbiter will continue for a year.


How will Chandrayaan 2 study the moon?

How does the ‘Pragyan’ rover operate and what determines its lifetime?

The time taken for the moon to complete one rotation on its axis is approximately equal to 29.5 earth days. This is also equal to the time it takes to complete one orbit around the earth. That is why the same side always faces the earth. But because it takes 29.5 earth days to complete one rotation, every point on its surface experiences daylight for about half the time, or a little more than 14 days at a stretch. Moon days are nearly 14 earth days long. Note that the landing is scheduled for September 6, when we will see the first quarter of the moon. This is a date when the lander will land at a point that is facing the earth and which has started receiving sunlight.

This point will receive light for nearly another fortnight which will match the expected lifetime of the lander-rover combo. Since the ‘Vikram’ lander and ‘Pragyan’ rover are powered by solar energy, they will be energised during this period by sunlight on the moon. Once night falls, this energy will not be available as they are plunged into a dark and cold -180º Celsius environment. If the lander-rover duo should kickstart after another half-rotation when day breaks once again, it will be a bonus for the ISRO.

The mission is not designed to survive this extreme cold, unlike some U.S. and Chinese missions which survived on the “dark” side of the moon using special sources of warmth.


How will the mission study the moon?

Using the Terrain Mapping Camera 2 which is on board the orbiter, the mission will produce images of the moon remotely from a 100 km lunar polar orbit. While the moon rotates about its axis, along its east-west direction, say, the lunar polar orbit will be in the perpendicular direction, along the lunar north-south direction. Thus, as the moon rotates, the orbiter gets a view of its entire surface from overhead. This data collected by the orbiter will be used to produce a 3D image of the moon’s terrain. This is just one of the eight instruments, or payloads, on board the orbiter. The lander carries three such payloads, some of which will measure the electron density and temperature near the lunar surface; the vertical temperature gradient, and seismicity around the landing site.

The rover will carry two instruments or payloads which will collect and test samples from the moon’s surface to identify what elements they contain. The rover moves on six wheels and once let down on the moon, can travel about 500 m from the lander.


What is the success rate of “soft-landing” on the moon?

There have been 38 attempts so far at “soft-landing” on the moon, with a success rate of 52% according to the ISRO website.


Why should we have this mission? Why should we study the moon?

The moon offers a pristine environment to study. It is also closer than other celestial bodies. Understanding how it formed and evolved can help us better understand the solar system and even earth itself. With space travel taking shape and exoplanets being discovered everyday, learning more about earth’s celestial neighbour can help in advanced missions. Finally, it is a piece of the larger puzzle as to how the solar system and its planets have evolved.

Costs

Chandrayaan 1 and 2, vis-à-vis the world

The cost of key USSR, US, Japanese, European, Chinese lunar missions and a comparison of the costs with Chandrayaan 1 and 2.
From: July 2, 2019: The Times of India


See graphic:

The cost of key USSR, US, Japanese, European, Chinese lunar missions and a comparison of the costs with Chandrayaan 1 and 2.

Personal tools
Namespaces

Variants
Actions