Missing the Moon By a Whisker

NO MISSION has evoked a deeper and a wider range of emotion at the Indian Space Research Organisation (ISRO) than Chandrayaan-2. On a high after scoring clean hits with its previous big-ticket missions, which found evidence of water on the moon and put an orbiter around Mars on a shoestring budget, ISRO was preparing for a historic moment: a dream touchdown near the lunar South Pole that would cement its standing as a Columbus of the space age. As the GSLV Mark 3 bearing Chandrayaan-2 lifted off on July 22nd after a minor snag, India was caught up in the power and the promise of the launch. Stowed in the composite spacecraft was Vikram, an indigenous quadrupedal lander carrying Pragyan the rover, a talisman inscribed with the Ashoka Chakra and the collective hopes of 1.4 billion people. In the first week of September, Vikram detached itself from the orbiter about 100 km from the surface of the moon, intending to land in time to make the best of the lunar daylight that would last 14 days. As per plan, in the early hours of September 7th, it began to execute an autonomous powered descent lasting about a quarter of an hour—“15 minutes of terror”, as ISRO Chairman K Sivan described it. During this time, the ground control team could do little but pray that it landed firmly on its legs. India cheered on, as though for an Olympic gymnast performing a spectacularly dangerous routine. Twelve minutes into the complex, multi-staged manoeuvre, the lander abruptly malfunctioned, going off course and losing contact with mission control. India’s latest and most ambitious space project had just been reduced, in the words of a senior ISRO scientist, to “an honourable miss”.

Had things gone as per script, Vikram and Pragyan, landing on a sunlit plain between two craters in a cloud of lunar regolith, would have been among the first—after China’s Chang’e-4 landed on the far side of the moon in January 2019—to look for water and Helium-3, a possible source of unlimited clean energy in the future, in the South Pole region before anyone else got there. Previous missions to the moon have landed in and around the equatorial region and have not studied the poles, which could potentially hold precious stores of water-ice in deep craters hitherto untouched by sunlight. India had hoped to be the first to shine a light into this reservoir of darkness. “If we had landed, it would have made a big impact internationally, wedging India between the US and China in the race to the moon. It was to be the precursor to future moon landings in the South Pole. It was a modest maiden effort, but we wanted to prove, as we did with the Mars mission and with Chandrayaan-1, that we could strike big with the limited resources available to us,” says Mylswami Annadurai, who saw through the successful launch of Chandrayaan-1 as project director. “Every ISRO mission is a culmination of strategic and scientific interests. In the case of Chandrayaan-2, the lander was the strategic part and the orbiter, containing eight new-generation instruments, is of high scientific value. But an orbiter is something we have done before—we put it together in just two years after successfully launching Mangalyaan,” Annadurai says.

Sivan has downplayed the faulty landing, calling it a “failed technological demonstration” and stressed that the orbiter, equipped with a high-resolution camera, a terrain-mapping camera, a dual-band synthetic aperture radar to look for sub-surface water-ice and an advanced IR spectrometer, besides other payloads, will continue to do important science and could be in orbit for up to seven years, although the planned lifetime was just a year. ISRO has once again demonstrated its mastery of orbiter mechanics and planning, but the failure to safely land Vikram, which has since been located lying tilted on the lunar surface, has deeply unsettled scientists, who say none of their simulations had prepared them for the eventuality of a crash or a loss of communications. Scientists at ISRO’s Telemetry, Tracking and Command Network facility in Bengaluru now labour on grimly to re-establish contact with the lander, knowing the chances of retrieving the unit or getting it to function as planned are bleak. “It is a nightmare situation for us. We were hoping to get some sleep after working long days for the past few months,” says a junior engineer. “This is just unbelievable. We had simulated everything, tested every part. In fact, during a test to ensure the load-bearing ability of the lander’s legs—they were originally supposed to fold out, but the design was later simplified—we had attached sensor blocks to them which introduced extra leverage and the test ended up failing. It had us worried at first before we figured out that the test itself was wrong. So you see, nothing was left to chance.” Employees say they have been warned not to talk to the media, lest they let slip information about mission planning and execution that could be held against ISRO while it is yet to announce the cause of the failure. “Space missions are always under scrutiny and ISRO officials are often asked not to reveal strategic information,” Annadurai says. “You may tell children to watch out so they don’t get hurt, but you don’t ask them not to play. I don’t recall such a time in my 36 years of service at ISRO.”

To be sure, there is a lot at stake, not the least of which is India’s confidence in landing on the moon despite a string of failed attempts, the latest being a private Israeli mission that crashed in April 2019. The moon, with its stark chiaroscuro of brightness and shadow, and its terrain slopes and hazards, is not an easy world to conquer. Dust, radiation and charged particles make the environment extremely unpredictable. The temperature on the lunar surface can vary from 200 degrees Celsius below zero in the dark polar regions to 120 degrees above zero during the day. The Indian capsule was designed to use solar energy to explore the area around the landing spot before the sun went down on it. In the absence of sunlight, the electronics aboard the Indian lander-rover duo were expected to fail, for unlike the Chang’e-4, China’s second lander mission, the Indian capsule is not equipped with radioisotope thermoelectric generators (RTG) to power its operations during the lunar night. Given the limited range of the rover—500 m, according to ISRO, although scientists who worked on the project say it could traverse up to twice the distance—however, no power source other than solar was considered necessary. “RTGs were part of the original design. There was concern about the handling of radioactives but the real reason we did away with them was that India does not yet make RTGs. We did not want to import this when the rest of the mission could be built in-house,” says a senior scientist who worked on the lander design.

A triumph of indigenous technologies, Chandrayaan-2 makes a powerful statement at a time when the US still uses Russian Soyuz rockets to send astronauts to the International Space Station. It is the flagship project of a new India that wants to leapfrog to a manned mission in 2022, with other exciting projects, including a Venus probe and a mission to study the sun, on the cards. As per an agreement signed in 2007 between ISRO and Roskosmos, the Russian Federal Space Agency, Chandrayaan-2 was supposed to be a joint mission with ISRO providing the orbiter and the rover and Roskosmos, the lander. Following a failure in December 2011 of Roskosmos’ Phobos-Grunt mission, however, Russia pulled out of Chandrayaan-2, originally scheduled to be launched in 2015. “We decided then to build everything ourselves,” says SVS Murty, a former scientist with the Physical Research Laboratory (PRL), a unit under ISRO, in Ahmedabad. “There was always a small chance that the lander, which we had no previous experience with, could crash. But we were left with no choice—we tried to build a reliable system that could automatically correct its course based on AI and used honeycomb design shock absorbers to handle hurdles and upsets.” The UR Rao Satellite Centre and the Laboratory for Electro-optical Systems in Bengaluru, and PRL and the Space Applications Centre in Ahmedabad jointly designed and built the orbiter, lander and rover and all the instruments onboard. Vikram carried payloads to study lunar seismic activity, the ionosphere and a surface thermo-physical experiment that would have helped Indian scientists understand heat flows on the moon. The six-wheeled Pragyan was equipped with a Laser-Induced Breakdown Spectroscope and an Alpha Particle-Induced X-ray Spectroscope to inspect and identify the composition of elements near the landing site.

“Given a chance, our scientists can design and build almost anything. But the results we achieve at ISRO are irreplicable elsewhere. Like wine from a certain terroir,” says N Vishwanatha, a former director of the Spacecraft Mechanisms Group, ISRO.

The group, which had been working on the rover from 2011 and certain parts of the lander for the past five years, is a cheerless one today. “Among the complex technologies we have built in the past is a six-metre-diameter S-Band unfurlable antenna for the GSAT-6 military communication satellite launched in 2015. We tried to buy the technology but the cost was more than that of the entire mission. We are one of the few countries that can make such a large antenna,” says Vishwanatha. “The mechanisms group holds the distinction of having performed 130 successive successful on-orbit deployments.”

ISRO is yet to fully analyse the landing manoeuvre to determine what went wrong, but among the theories that have emerged is that one or more of the lander’s five engines failed to properly de-boost in the terminal phase of the descent. Those who have worked on the project say the fifth engine was a late addition made to ensure a smooth descent, and not a redundancy. “Changes must not be made so late into a project,” says a former mission planner. “Ambition is great and inspiring but not at the cost of stressing out scientists. Many of them are sleepless and on the brink of burnout. They are being denied leave.” Those of us hymning the virtues of competitive space science have only a foggy sense of the unremitting demands it makes of our engineers. In his interaction with ISRO scientists in Bengaluru, when Prime Minister Narendra Modi acknowledged their dedication, he was rewarded with guileless smiles. “You are the ones who live for the country,” he said. “You are the ones who sacrifice your own dreams and spend sleepless nights to keep India’s head high.”

Others say that the meticulous review system at ISRO leaves little to chance. “The plus point of ISRO is the excellent review system at various levels. If you have a technical doubt, you can raise it irrespective of your rank. This is a culture that we have inherited from Dr Sarabhai, Dr Satish Dhawan and others who have led the organisation. This is the secret behind our resilience,” says V Adimurthy, mission concept designer for the Mars Orbiter Mission, who is now Dean of Research at the Indian Institute of Space Science and Technology. “The one thing we were clear about was that we had to do the best thing that had not been done—whatever the outcome. Because whatever resources we may lack, we make up for with courage.”

Indian space science is a unique cocktail of courage, hard work and improvisation—“jugaad”—says Annadurai. “In 2004, when we were sanctioned Rs 25-30 crore to build a lunar terrain simulation facility in Bengaluru for Chandrayaan-1, we first bought 10 kg of lunar simulant for $150 a kilo. But we needed 60-70 tonnes and it was working out to be too expensive. With help from soil experts at Periyar University and IISc, we identified similar soil and rocks in a village near Salem in Tamil Nadu and acquired it almost free of cost. We took over a shed formerly occupied by a stratospheric balloon-testing facility and recreated the moon’s surface there,” he says.

Space missions are catechisms for man’s ambition, especially now that the rhetoric of saving humanity by venturing to the moon has become every billionaire’s dream. Elon Musk, Jeff Bezos and Robert Bigelow all hope to bring people and materials to the moon in the near future. The moon is not just a trove of resources and minerals we are fast running out of on earth, but with one-sixth the gravity, it is an attractive stepping stone for greater cosmic journeys of the future. Mining the water-ice on the poles and turning it into hydrogen-oxygen rocket propellant no longer seems inconceivable for a space-faring civilisation. For Chang’e-4, named after the Chinese moon goddess, finding and extracting helium isotopes is a key priority. It will also study moon dust and try to melt it using sunlight to develop a sturdy construction material. The US, which recently launched a programme called Artemis to take Americans to the moon by 2024, plans to build a large space station orbiting the moon and a fleet of heavy-lift rockets.

For India, the moon could be a perch to set up telescopes through which to peer deeper into the galaxy. “By the end of the Cold War, after a few people had jumped around on the moon and picked up stones, there was nothing left to do. The target to reach the moon had been achieved. The second phase of lunar exploration, which has picked up pace in the past few years, is driven by a hunger for resources to feed the future needs of the human race,” says Ajey Lele, a senior fellow at the Institute of Defence Studies and Analysis who works on space security and strategic technologies. “Despite technology limitations and with just a small rover, ISRO wanted to do a mission that would not just be an advertisement, but also give it a scientific advantage. India’s priority is finding water,” he says. “Location matters. We chose to land in a place where we were bound to discover something new. We are not competing with China, but we are trying to break new ground in our own way.” ISRO’s next priority is the $1.4 billion Gaganyaan mission, which aims to launch three Indian ‘gaganauts’, at least one of them a woman, into space. Astronauts for the mission will be trained in Russia even as India is working on setting up a training centre for a second-generation of space-men and -women in Bengaluru, where ISRO’s new Human Space Flight Centre is also located.

ISRO has come a long way in the past 30 years, using every failure to inform and enrich successive missions. At an informal meeting of retired ISRO scientists at the Aeronautics Society of India, Bengaluru, two days after India lost contact with the lander, grey-haired south Indian gentlemen recount stories of spectacular failures. The first experimental flight of SLV-3, in August 1979, launched from Sriharikota by the then mission director APJ Abdul Kalam via a manual override despite a system warning, failed, plunging the Rohini satellite into the Bay of Bengal. The same team managed to launch it successfully on July 18th, 1980. Through the 1980s and the 1990s, failure was a rite of passage as India worked to achieve independent access to space with SLV and ASLV rockets. “Even in a successful mission, there are underperformances that you don’t hear about. We learn from these—this is how redundancies come to be built into launch systems,” says G Ravindranath, who worked on SLV, ASLV, GSLV and the cryogenic project and retired as GSLV project director. Indian scientists made basic errors that momentarily set the space programme back. In 1993, the first PSLV flight ended in failure due to a software overflow—which would be an obvious check today. Ravindranath, who lost two missions, says the entire crew got emotional both times. “Thankfully, we didn’t have TV cameras hovering over us. When the GSLV-D3 failed due to a malfunctioning of the indigenously developed cryogenic stage, we lost the satellite too. It was an expensive mission. But we learned from it.”

India’s failure to roll out a moon buggy on its maiden attempt is not an Icarus fable. A crash wasn’t a likely situation, it simply was a possible one. Ever fleet of foot, ISRO remains as eager to strike out into new scientific territory as it was when it set out on an impossible voyage to the red planet. “We will not turn tail,” says a Chandrayaan-1 mission planner. “Once we have found the granular element that must be got right, we will focus on the next project—actually, several—at hand.”

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