India lands on the moon
The third lunar mission of India to study permanently shadowed craters: An Israeli nonprofit, the United States and Israel have failed to land on the Moon
The country has become the first to land a probe near the Moon’s rock and crater-strewn south pole.
Excited and anxious, people across India, home to the world’s largest population, crowded around televisions in offices, shops, restaurants and homes. Thousands prayed Tuesday for the success of the mission with oil lamps on the river banks, temples and religious places, including the holy city of Varanasi in northern India.
Chandrayaan 3, India’s third lunar mission, lifted off on 14 July. A six-wheeled robotic rover called ‘Prowyan’ is the centerpiece of the landing module that was carried by the launch. Pragyan will ramble around the landing site for one lunar day, equivalent to 14 Earth days.
Many countries and private companies are interested in the south pole region because permanently shadowed craters may hold frozen water that could help future astronaut missions.
The Chandrayaan 3 landers and rover module are configured to give the scientific community data on the properties of lunar soil and rocks.
“The recent crash of Russia’s Luna 25 spacecraft is a stark reminder of just how difficult it is to land successfully on the Moon,” says Marc Norman, planetary geochemist at the Australian National University in Canberra. Israel and Japan have had crashes while attempting controlled landings on the Moon. Only China has landed successfully on the Moon in the last few years. The United States and the Soviet Union have put craft on the moon.
A $140 million mission was planned to study permanently shadowed moon craters that are thought to contain water and were confirmed by India in 2008.
After Russia’s failed attempt to land a rocket, there was more anticipation for a successful landing. The Chinese government launched a three person crew for its space station in May and plans to land astronauts on the moon before the end of the decade. There have been disagreements between India and China in the past.
Numerous countries and private companies are racing to successfully land a spacecraft on the lunar surface. The Japanese company was attempting to make a landing on the moon. An Israeli nonprofit tried to achieve a similar feat in 2019, but its spacecraft was destroyed on impact.
An X-ray telescope mission by Japan will be followed by a lunar landers launch later this weekend. The two US companies competing to land on the moon are both at the south pole. NASA plans to land astronauts on the lunar south pole in the coming years, taking advantage of the frozen water in craters.
Launching of the Russian spacecraft Luna 25 at the Moon’s south pole on August 19, 2005 at 8:14 a.m. Eastern time
India’s success instills faith in its space industry, says a mission systems engineer at Bengaluru-based company KaleidEO. Karampuri said it could attract global investments in the Indian private space sector and foster international collaboration.
The landers is in a close fly past of the moon, flying as close as 15 miles above the surface. On Wednesday at around 8:14 a.m. Eastern time, ISRO says the spacecraft will fire its engines to bring itself out of orbit and begin a descent to the surface. The engines will further brake its fall, to help it achieve a soft landing.
The nation’s space program, the Indian Space Research Organization, will provide a livestream from the mission control room in Bengaluru. You can watch it on ISRO’s YouTube channel or website starting at 7:50 a.m. Eastern.
The landing site is in the afternoon on the day of the sun’s rise. The mission is to conclude two weeks later when the sun sets. While on the surface, the solar-powered lander and rover will use a range of instruments to make thermal, seismic and mineralogical measurements.
The Moon’s south pole — a challenging region to land in — has drawn interest from many nations because of the possibility that it contains water ice, and the large craters near it could offer clues about the composition of the early Solar System. The Russian craft Luna 25 crashed into the Moon on August 19 before it could land at the south pole, just days before several missions are headed there.
The power descent phase began at about 8:15 am ET, during which time the craft’s speed slowed from 1,680 to 358 meters per second, and the altitude dropped from 30 to 7.4 kilometers over a period of 11.5 minutes. During the following altitude hold phase, for 10 seconds the craft turned its altimeters towards the moon’s surface to take a reading of how far it was from the regolith. After a few moments the fine brakes phrase began, as the altitude was reduced to 800 meters.
The vertical descent began shortly after 8:29 am Eastern time, as the craft began its approach to the lunar surface. It briefly hovered 150 meters above the surface as the craft’s sensors took readings of the safety of the landing site and re-targeted accordingly. People in the mission control headquarters broke into applause after it set down on the regolith. “India is on the moon!” exclaimed ISRO chairman Vikram Sarabhai. Prime Minister Narendra Modi was watching the show remotely, and Sarabhai asked him to speak. “Friends, on this joyous occasion I would like to address all the people of the world, the people of every country and region. Modi said in his address that the moon mission is not only India’s alone. This success will help moon missions by other countries in the future. I’m confident that all countries in the world, including those from the global south, are capable of achieving such things. We all have an ambition for the moon and beyond.
The landing gave confidence to the people that there are missions going to the moon, Mars, Venus, and maybe even asteroids.
These include a new laser sensor to measure the real-time velocity of the spacecraft relative to the Moon, algorithms to handle unanticipated deviations in propulsion or trajectory and better judge the landing terrain, bigger and more solar panels, more fuel, a heavier lander equipped with four sturdier legs to handle a faster landing velocity.
Landing at the Moon’s south pole is difficult because it involves positioning the spacecraft at a different angle from previous landings, and the area has rough terrain.
In particular, it requires putting the spacecraft into a polar orbit that is at right angles to the Moon’s orbit, says Norman. “This requires additional energy to move the spacecraft into an ‘unnatural’ orbit, which introduces uncertainties on critical aspects such as velocity and location of the spacecraft.”
The lack of data on the region’s gravity and surface characteristics are related to the problem. “For example, if the spacecraft lands in a crater, on a slope, or the leg of the lander catches on a boulder, the mission could be compromised.”
Moon quakes near the area add complexity, says geologist Saumitra Mukherjee at the Jawaharlal Nehru University in New Delhi, whose team analysed images sent by India’s first lunar mission, Chadrayaan-1, which launched in 2008 and detected cliffs and signs of displaced underground rocks in two craters near the lunar south pole.
There are challenges that come from poor lighting from the Sun. “Some areas are completely in the dark, other areas are in the light, but with extreme sun angles blocking out any terrain features,” says Torin Clark, an engineer at University of Colorado Boulder. The landing sites and timing were selected specifically to ensure quality lighting of the lunar terrain, like rocks and craters.
