Chandrayaan (India’s moon mission)
This is a collection of articles archived for the excellence of their content.
Why does India/ the world want moon missions?
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
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.
2019, Sept: India and other countries with lunar missions
2019, Sept: India’s position among countries with lunar missions
Research and development
How to land on the moon
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.
Decision making process of Chandrayaan- I
'Lost' in 2009; NASA finds it orbiting Moon in 2017
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
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
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
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.
Vis-à-vis US, USSR missions
A COMPARISON OF LUNARCRAFT LAUNCHERS OF ISRO & NASA
Have you wondered why Chandrayaan-2 will take 48 days to reach Moon whereas missions launched by USSR and US over five decades ago reached the lunar surface in under a few days?
USSR’s Luna-2 craft took just 34 hours to reach Moon in 1959. Ten years later on July 20, 1969, Nasa’s Apollo-11 mission carrying humans landed on Moon in just four days, 6 hours and 45 minutes. Besides being the world’s first manned Moon mission, Apollo-11 was also the fastest trip of astronauts to the Moon.
So why is Chandrayaan-2 taking more than a month? The answer lies in the build of the rocket, the amount of fuel it’s carrying and the speed of the lunarcraft.
In space, covering long distances requires high speeds and straight trajectories. For Apollo-11, Nasa had used Saturn V, a super heavy-lift launcher, to travel at more than 39,000km per hour. The powerful rocket had a lifting capability of 43 tonnes, including the lunar module, service module and command module housing the crew capsule. Saturn V’s third stage put the modules (command with crew capsule, service and lunar modules) into the trans-lunar trajectory soon after orbiting Earth for the second time (see graphic below). The launcher and the lunar craft used powerful engines to reach Moon covering 3.8 lakh km in just four days. However, Nasa had to pump in $185 million ($1.2 billion in 2016 value) for each Apollo mission between 1969 & 1971. Of the $185 million, it spent $110m ($690m in 2016 value) on every Saturn V.
India does not have a rocket powerful enough to hurl Chandrayaan-2 on a straight path to Moon. It’s the reason Isro chose a circuitous route to take advantage of Earth’s gravity, which will help slingshot the craft towards the Moon. The role of GSLV-MkIII, with only 4-tonne lifting capability, was limited to putting Chandrayaan-2 (3.8 tonnes) in the geosynchronous transfer orbit. Currently, the lunarcraft’s propulsion system is raising its orbit. Once the craft reaches its apogee (farthest point from Earth), and with added acceleration, the final orbit will become so stretched out that the farthest part will be very close to Moon’s orbit.
Isro chairman K Sivan told TOI, “The spacecraft requires a minimum velocity of 11km/ second to go to Moon. Of that, 10.3km/second is provided by the vehicle and 700m/second is being provided by the craft’s propulsion system. Being a small engine, we are burning the engine not continously but in short bursts to manoeuvre the craft. If we had a powerful engine like Saturn V, we could have reached Moon in a single shot.” He added, “We are using Moon’s gravitational pull to take craft to the lunar orbit. Though we are taking 29 days to reach the lunar orbit, this is the most cost-effective way to travel to Moon.”
Isro invested Rs 978cr in the Chandrayaan-2 mission. Rs 375cr ($142m) of the total was spent on building GSLVMkIII, a fraction compared to what Nasa had spent on Saturn V.
ISRO’S GSLV-MKIII CARRYING CHANDRAYAAN-2
The three-stage rocket is Isro’s heaviest lifter with the capacity to carry up to 4 tonnes. Though it’s called Isro’s ‘Bahubali’, the rocket is no match for Nasa’s Saturn V. GSLV-MkIII is 43.4m in height (as tall as a 14-storey building) and weighs 641 tonnes. It carried the module to the geosynchronous transfer orbit.
NASA’S SATURN V CARRIED APOLLO-11
Nasa’s heavy-lift vehicle was a three-stage liquid-propellant rocket. As of 2019, Saturn V is the tallest (111 metre or a 36-storey building), heaviest (2,950 tonnes) and most powerful rocket built. It had the largest payload capacity of 140 tonnes, which included third stage and unburnt propellant to send a command and service module and lunar module to the Moon. Saturn V carried a 43-tonne payload.
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
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”.
How will Chandrayaan II study the moon?
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.
2019: The planned path
Chandrayaan 2: The planned path
Why the July 2019 launch was postponed
Working overnight on the aborted Chandrayaan-2, the Indian Space Research Organisation (Isro) teams have pinpointed the leak in the GSLV-MkIII cryogenic engine to a ‘nipple joint’ of the helium gas bottle that supplies pressure to the fuel and oxidiser. Why it happened remains the crucial question Isro engineers are trying to answer.
Isro had aborted the Chandrayaan-2 launch 56 minutes before its scheduled lift-off at 2.51am on Monday.
“The good news is that we can fix the leak without dismantling the rocket, since there is an access door to the gas bottle which is atop the oxygen tank,” a senior scientist told TOI. “The bad news is that unless we ascertain the reason for the leak, there is a probability of the problem recurring.” Not having to dismantle means Chandrayaan-2 may be able to fly before the end of the July launch window, but a final failure analysis will be available only in a day or two.
Sources told TOI that the leak wasn’t serious enough to impair the flight, but Isro decided to apply “abundant caution,” given the importance of the Rs 978-crore project that would make India only the fourth country – after the US, Russia and China – to land a craft on the lunar surface.
The helium gas bottle has a capacity of 34 litres and it was to be pressured up to 350 bars before regulating the output to 50 bars. “The leak was bringing down the pressure by four bars per minute. The rocket could’ve still made it, but we didn’t want to take any chances,” a source said.
A veteran of Isro failure analysis said teams would now look at the proximity of the faulty ‘nipple joint’ to the oxidiser tank that stores liquid oxygen at minus 183 degrees Celsius. “If the joint was close to such a low temperature, the reason could be micro shrinkage of the joint. In that case we need to insulate it or shift the joint away from the coldest point,” the scientist said.
Bigger leaks in the gas bottle can, besides affecting combustion and velocity, send the rocket spinning out of control. For now, Isro is confident of rectifying the fault and flying to moon without much delay.
More than 7,000 people from across the country had gone to the Sriharikota spaceport to witness the Monday launch. President Ram Nath Kovind was with senior Isro scientists at the mission control centre when the launch was called off at 1.55am.
The Cryogenic Upper Stage
The ABC of Cryogenic upper stage
How Isro toiled for years to develop cryo engine
SRIHARIKOTA: A technical snag in the cryogenic stage of the GSLV-MkIII rocket carrying Chandrayaan-2 module had stalled Isro’s launch of the moon mission on July 15. Though the space agency successfully launched the mission in its second attempt on Monday after taking great efforts to fix the snag, the moot question is why it is so difficult to deal with a snag in the cryogenic upper stage of GSLV Mk III, popular as 'Bahubali' . To know about the cryo stage snag, first an understanding of the art of cryogenics is needed. Among all rocket fuels, hydrogen is known to provide enormous thrust as compared to solid and earth-storable liquid propellants. But hydrogen in its natural gaseous form is difficult to store and handle, and is, therefore, not used in normal engines like that of PSLV. However, hydrogen in liquid form can be stored in a rocket engine but that requires it to be maintained at a very low temperature — minus 253 degrees Celsius. And to burn the liquid fuel, oxygen too needs to be in liquid form — minus 187 degrees Celsius. Creating an atmosphere of such low temperatures in the rocket is quite challenging as it creates problem for other materials.
Over 25-30 years ago, Isro was desperate to develop the cryogenic technology for its GSLV rocket in order to lift heavier payload of over 3-4 tonnnes into the geo orbit at 36,000km altitude, from where it could send its spacecraft to deep space or other planets. This was because Isro’s mainstay rocket PSLV without a cryogenic engine, could deliver payload only up to 1.7 tonne to the lower earth orbit up to an altitude of 600 km. It could go to geo tranfer orbit but at reduced payload. Though PSLV was used for launching India’s first moon mission Chandrayaan-1 in 2008 and Mars Orbiter Mission in 2014, in both the cases the payload was not above 1.4 tonne.
In early 1990s, India had approached the US, Soviet Union, Japan and France for cryo technology. Only Soviet Union came forward. But Moscow too stepped back when the US cited a violation of the international Missile Technology Control Regime (MTCR) to threaten it and imposed sanctions on Isro and Soviet Union's launch service provider Glavkosmos. Though the US threat stalled the transfer of Russian cryo technology, India still managed to import seven such engines from Glavkosmos. The engines were used to launch initial versions of GSLV rockets. But desperate to have an indigenous technology, Isro scientists worked tirelessly for over two decades to develop its own cryo engine. Being a complex system, Isro still faces some hiccups in its cryo stage like the July 15 snag.
The July 15 glitch was due to a leak in helium bottle joint in the cryo upper stage (Helium is used to maintain pressure in the cryogenic chamber). The leak occurred after the propellant tanks were filled with liquid hydrogen, the fuel, and liquid oxygen, the oxidiser. With the pressure not holding in the cryogenic chamber, the mission control centre had no option but to call off the liftoff.
Making lunar spacecraft think and act
Within a week after Chandrayaan-1 was launched in 2008, scientists had to abort a manoeuvre of the spacecraft as all ground stations lost visibility. But that did not hamper the mission, as the spacecraft used its own electronic brain fed with commands in advance to manoeuvre on its own. Six years later, it is with the same ebrain that Mangalyaan found its way to Mars by correcting its altitude and the position of its antenna and solar panels during its 300-day journey. Rocket science calls it autonomy.
With Chandrayaan-2, Isro will once again demonstrate its mastery over autonomy when Vikram will soft land on the south pole on its own sans intervention from ground control. And that is going to keep India in good stead as Isro plans future interplanetary missions.
“It’s like an aircraft on auto-pilot. Vikram will have only one chance. It has to see the landing place correctly, reduce its velocity and land with minimal impact,” said Chandrayaan-1 project director Mylsamy Annadurai.
Rover Pragyan, too, will work on its own. It will have the ability to ‘think’ it is not in the right position and move back to its last step if it does not receive commands from the ground station.
India has planned seven inter-planetary missions in the next 10 years, starting with Xposat to study cosmic radiation in 2020, Aditya L1 to Sun in 2021, Mars Orbiter Mission-2 in 2022, a date with Venus in 2023, Lunar Polar Exploration or Chandrayaan-3 in 2024 and Exoworlds, an exploration outside the solar system, in 2028.
Simultaneously, as it adds more satellites to meet its demands, monitoring and controlling from the ground could become humanly impossible. Injecting smarter satellites into orbit meant it can decide autonomously what, when and how to carry out operational tasks, like capturing images of Earth, analyse and process them before selecting important data for downloading to the earth station. This also allows satellites to communicate with each other and do tasks like identifying a target to be monitored continuously, like a moving vehicle.
“This is an electronics revolution. It simply puts intelligence into a satellite,” said TK Alex, former director of UR Rao Satellite Centre. “On the software side, India is on the top.”
Extra brake thrust may have sent Vikram out of control
Isro Searched For Links From Nasa Centre, But To No Avail
When silence descended upon the Isro mission control and millions of Indian homes minutes before Vikram was to touch down on the Moon at 1.53am on Saturday, many thought the lander had too little thrust to brake to a halt. A day later, Isro scientists are looking at whether Vikram had too much braking thrust, which spun it out of control.
“We thought one of the thrusters may have underperformed,” said an Isro scientist. “But after some preliminary analysis, it looks like a thruster overperfor med.”
Descending from its orbit 30km from the Moon, Vikram had achieved perfect roughbraking for 10 minutes, reducing its velocity from 1,680 metres per second to 146 metres per second. Soon after the fine-braking that signalled Vikram’s last 5km descent to the Moon, mission control lost contact with the lander.
Officially, Isro maintained that data was still being analysed. However, a scientist told TOI, “Vikram’s legs were to be horizontal during the roughbraking and had to be rotated by 90 degrees to bring them vertical to the landing surface before fine-braking. At this point, the thrust might have been more than optimal, impacting the lander’s orientation. It’s like a car losing direction due to sudden braking at high speed.”
When Vikram went silent, Isro mission control searched for links from Nasa’s deep space network centre in Madrid and the Indian station in Mauritius, but to no avail.
90-95% of mission objectives achieved
The space agency also underscored that 90-95 per cent of the mission objectives had been achieved and would contribute to lunar science despite the loss of communication with the Vikram lander.
In its first statement after moon mission suffered a huge setback on Saturday, the Indian Space Research Organisation described India’s Chandrayaan-2 as a highly-complex mission that represented a “significant technological leap”.
The space agency also underscored that 90-95 per cent of the mission objectives had been achieved and would contribute to lunar science despite the loss of communication with the Vikram lander.
It specifically counted the precise launch and the mission management as one success area, one that would enable the Orbiter to stay in place for the next seven years instead of the planned one year.
“This was a unique mission which aimed at studying not just one area of the Moon but all the areas combining the exosphere, the surface as well as the sub-surface of the moon in a single mission,” the statement said.
The Vikram Lander followed the planned descent trajectory from its orbit of 35 km to just below 2 km above the surface. The statement did not spell out what exactly had happened beyond this point.
Chandrayaan 2: Achieved 90-95% objectives, says ISRO chief K Sivan
In its first statement after moon mission suffered a huge setback, the Indian Space Research Organisation described India’s Chandrayaan-2 as a highly-complex mission that represented a “significant technological leap”.
But till then, the statement said, all the systems and sensors of the Lander “functioned excellently” and proved many new technologies such as what it called “the variable thrust propulsion technology”.
“The Orbiter has already been placed in its intended orbit around the Moon and shall enrich our understanding of the moon’s evolution and mapping of the minerals and water molecules in the Polar Regions, using its eight state-of-the-art scientific instruments,” the statement said.
The Orbiter camera is the highest resolution camera (0.3m) in any lunar mission so far and shall provide high resolution images which will be immensely useful to the global scientific community. Isro said it would have a long life of almost 7 years instead of the planned one year.
The success in placing the Orbiter was a point that has been highlighted by Prime Minister Narendra Modi as well, first in his televised address to the Isro scientists and later at the inauguration of metro projects in Mumbai.
“We have to remember that orbiter is still there... This is also a historic achievement,” he said in Mumbai.
Hours earlier, Prime Minister Modi had comforted crestfallen scientists and a stunned nation from mission control in Bengaluru.
In the early hours of Saturday, the Vikram lander - named after Vikram Sarabhai, the father of India’s space programme - had gone silent just 2.1 kilometres above the lunar surface.
PM Modi told scientists to not lose heart and thanked them for the milestones achieved during this historic attempt. “It is not a small achievement and the country is proud of you. If the communication starts again, then the mission will be able to give us a lot of information. Let’s hope for the best,” he said.
The Orbiter continues looking for water, minerals
With 8 payloads, probe to look for water, minerals
All is not lost with Vikram and Pragyan losing contact with Indian Space Research Organisation (Isro) moments before their scheduled landing. Their separated brother, the lunar orbiter, is going around the Moon, collecting valuable information on possibility of finding water and minerals.
Equipped with eight payloads, the orbiter, that has been in place since September 1, has a life span of more than seven years.
Nasa veteran Jerry Linenger, who had flown on space shuttles and spent five months on Russian space station Mir in 1997, said, “With Chandrayaan-2’s orbiter doing three-dimensional mapping of the Moon and looking beneath the lunar surface, we are expecting a lot of information. Anyone looking to set up a base on Moon will be benefited by such infor mation.”
Retired Isro scientist M Annadurai, who was the project director of the 2008 Chandrayaan-1 mission, told TOI that the orbiter does many things that the lander and the rover couldn’t have. “While the rover’s research area would have been 500 metres, the orbiter will map the entire Moon from an altitude of about 100km. Onboard equipment such as IR spectrometer, two cameras and dual-band synthetic aperture radar can do a lot,” Annadurai said.
“The IR spectrometer covers the entire Moon to study what three payloads of Chandrayaan-1 — India’s hyperspectral imager, Germany’s near infrared spectrometer and Nasa’s moon mineralogy mapper — have done,” he added.
The Chandrayaan-2 orbiter’s terrain mapping camera has a spatial resolution of 5m and a swath of 20km, which will help Isro prepare 3D maps of the lunar surface. The high-resolution camera can pick up details as small as 30cm (Chandrayaan-1 camera had 1m resolution). The indigenous synthetic aperture radar used this time has dual band (frequency), whereas the Nasa-imported one used in Chandrayaan-1 had just one band.
Another senior Isro scientist told TOI that the synthetic aperture radar will help Isro make accurate estimates of water in the polar craters. “It can capture images of lunar rocks of up to one foot. This camera will be used in the Cartosat-3 series of surveillance satellites and also the Indo-US joint venture NISAR satellite due for launch in 2022,” he said.
Not a failed mission
World media, experts
BENGALURU: International space experts and media around the world called the communication loss with Vikram lander a "partial loss" and said "all is not lost" as the orbiter with key scientific instruments on board is still circling Moon's orbit.
Former US astronaut and space analyst Jerry M Linenger said, “India was trying to do something very, very difficult. Everything was going as planned as the lander came down. Unfortunately, it never quite made it to the hover point. That would be at an altitude of about 400 metre if it had made it to that point, and even if it had not succeeded beyond that, it would have been helpful because the radar altimeters and lasers could have been tested. This would obviously be very helpful for follow-on missions. Overall, the mission has been very successful."
He said, "The orbiter will continue to downlink very valuable information for the next year. And by all indications, all systems are go on the orbiter. I look forward to watching complete success in the future based upon lessons learned from this bold attempt.”
Writer and managing editor of Nasa Spaceflight Chris G said, "The orbiter is where 95 per cent of the experiments are. The orbiter is safely in lunar orbit and performing its mission. This is not a total failure. Not at all," Chris G tweeted.
Israel, whose Beresheet lander crashlanded in April this year, too responded positively about the Chandrayaan-2 mission. Israel ambassador Ron Malka tweeted, "Take pride India and have courage. This is a great achievement and it is not the end. Israel is no stranger to the stumbling blocks on the way to a soft landing and we know India will try again and complete the last step. We will see you there. #IndiaOnTheMoon"
Most of the world newspapers did not call India's mission a total failure.
"All is not lost for the mission", the online edition of US magazine 'Wired' said on Vikram's "deviation from its expected trajectory". The New York Times lauded India's "engineering prowess and decades of space development have combined with its global ambitions."
'The Guardian', in its article titled -- India's moon landing suffers last-minute communications loss, quoted Mathieu Weiss, a representative in India for France's space agency CNES, as saying, "India is going where probably the future settlements of humans will be in 20 years, in 50 years, 100 years."
Amid the increasing hostility with Pakistan, its minister for science and technology Fawad Chaudhry only made a sarcastic remark on Vikram lander. "Please sleep. The toy landed in Mumbai instead of landing on the moon," he tweeted.
American magazine Wired said the Chandrayaan-2 programme was India's "most ambitious" space mission yet.
"The loss of the Vikram lander and the Pragyan rover it was carrying to the lunar surface would be a big blow for India's space program...but all is not lost for the mission," it said.
The Washington Post in its headline "India's first attempt to land on the moon appears to have failed" said the mission had been a source of "immense national pride". "Social media erupted in support of the space agency and its scientists despite the setback... The incident could now set back India's growing space ambitions, seen as a reflection of the aspirations of its young population," it said.
"One of the successes of India's space program has been its cost-effectiveness. Chandrayaan-2 cost $141 million, a small fraction of what the United States spent on its historic Apollo moon mission," the report said. American network CNN described it "India's historic landing on moon's polar surface may have failed".
"India's historic attempt to soft land a rover on the moon may have ended in failure moments... The crowd had celebrated every small step during the controlled descent and the moment the landing was expected to take place, silence descended," it said.
The BBC wrote the mission had made global headlines because it was "so cheap".
"The budget for Avengers: Endgame, for instance, was more than double at an estimated $356 million. But this isn't the first time Isro has been hailed for its thrift. Its 2014 Mars mission cost $74 million, a tenth of the budget for the American Maven orbiter," it said.
French daily Le Monde mentioned the success rate of soft landing on the moon.
It said, "so far, scientists point out, only 45 per cent of missions aimed at alleviating have been successful".
It started its article with words "A broken dream" and said that the Indian newspapers "were quick to titrate their websites, after announcing the worse scenario that could expect the Indian Space Research Organisation". In the early hours of Saturday, Indian space agency Isro's plan to soft land Chandrayaan-2's Vikram module on the lunar surface did not go as per script.
The lander lost communication with ground stations during its final descent. Isro officials said, adding that the orbiter of Chandrayaan-2 - second lunar mission - remains healthy and safe.
Prime Minister Narendra Modi asked Isro scientists not to get disheartened by the hurdles in the moon mission Chandrayaan-2 and asserted that there will be a "new dawn and better tomorrow". ( With agency inputs)
Shanmuga Subramanian locates the lander’s debris
NEW DELHI: After almost three months of frantic search for the Vikram lander by space scientists and space agencies from across the world, it was a techie from Chennai who found the debris of Chandrayaan-2's Vikram lander on Moon's south pole by using US space agency Nasa images.
Shanmuga Subramanian (Shan), a mechanical engineer and a computer programmer who works as a technical architect at engineering company Lennox India Technology Centre in Chennai, has made India's greatest space discovery of the lander, which had made a hard-landing on Moon's surface during a landing attempt on September 7, 2019.
Shanmuga, who hails from Madurai and had earlier worked for Cognizant as a programme analyst, used lunar images from Nasa's Moon's Lunar Reconnaissance Orbiter (LRO) captured on different dates (September 17, October 14, 15 and November 11) and studied them for weeks to locate the debris of the lander.
After making the discovery, Shanmuga wrote to Nasa informing it about his findings for which the US space agency took some time to confirm it. Authenticating his discovery finally, Nasa's deputy project scientist (LRO mission) John Keller wrote to him, "Thank you for your email informing us of your discovery of debris from the Vikram lander. The LROC team confirmed that the location does exhibit changes in images taken before and after the date of the landing. Using the information, the LROC team did additional searches in this area and located the site of the primary impact as well as other debris around the impact location and has announced the sighting on the Nasa and ASU pages where you have been given credit for your observation."
Wishing Shanmuga for his hard work, Keller further wrote, "Congratulations for what I am sure was a lot of time and effort on your part. We apologise for the delay in getting back to you as we needed to be certain of our interpretation as well as making sure that all stakeholders had an opportunity to comment before we could announce the results".
Later, confirming news to the world, Nasa tweeted: "The Chandrayaan-2 Vikram lander has been found by our NasaMoon mission, the Lunar Reconnaissance Orbiter. See the first mosaic of the impact site." An image of Moon with blue and green dots show the impact point of Vikram and an associated debris field.
"Green dots indicate spacecraft debris. Blue dots locate disturbed soil, likely where small bits of the spacecraft churned up the regolith (moon soil). "S" indicates debris identified by Shanmuga Subramanian," the Nasa statement read. The debris, first located by Shanmuga, is about 750 metre northwest of the crash site.
Indian Space Research Organisation (Isro) and Nasa have been looking for the Vikram lander + since September 7. In fact, Nasa had used its deep space network antennas in California, Madrid and Canberra to send signals to the Vikram lander with the hope that it would reflect the signals if the lander's systems were working but all the US space agency's efforts went in vain. Finally, it used its orbiter LRO, circling around the Moon, to take images of the south pole region to locate the lander. Isro, too, has been using Chandrayaan-2's functional orbiter, circling Moon at 100km altitude, to scan the landing zone to look for the lander.
Recently, in a written reply to a question in the Lok Sabha, Union minister for department of space Jitendra Singh explained the reason for the Vikram's hardlanding. He said, "During the second phase of descent (of lander), the reduction in velocity was more than the designed value. Due to this deviation, the initial conditions at the start of the fine braking phase were beyond the designed parameters. As a result, Vikram hard-landed within 500 metres of the designated landing site."
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.