Moon missions are as risky today as they were 60 years ago. NASA’s failed Peregrine mission is a reminder that getting humans back to the moon is years off. The Americans landed people on the moon in 1969 with less computing power than our contemporary phones. So, why do we find it so hard to land on the moon today?
Heard that before? We have. It has become one of those irritating cliches that contain an element of truth. It is also a question that deserves an answer, with Russia, India, the United States, China, Japan, and Israel all racing to get to the moon again—sometimes within a week of each other.
The US and China want to send humans to the moon
Missions to the moon have varied goals, but the main one is getting people back on the surface of the moon. But it is as tough today as it was between 1969 and 1972 when NASA successfully landed humans on the moon six times. One mission, Apollo 13, failed to land.
Also Read | Shooting for the stars with feet of clay
In early January 2024, NASA and a commercial partner, Astrobotic, took a first step towards returning US robotic instruments to the moon, but failed. They said their Peregrine One spacecraft had “no chance of a soft landing on the moon”—meaning, it would crash land, if at all.
Soon after the Peregrine One had launched and separated from its rocket, itself a new Vulcan carrier made by United Launch Alliance, the propulsion system failed, causing external damage to the spacecraft and a critical loss of fuel. Peregrine One was part of NASA’s Artemis program and an essential step before a crewed mission to the moon in 2025. Those plans have now been delayed by at least one year, said NASA.
Since this follows an earlier failed test launch by SpaceX’s Starship rocket, there may be more delays to come, but not less pressure to be the first: China is targeting 2030 for a crewed landing.
Moon landings at the South Pole
Other nations are test-landing in difficult locations, such as at the South Pole. Most of the landings by the USA and Cold War-era Russia landed in around an “easier” central belt of the moon. And Peregrine One was also going to land in that area—around the Bay of Stickiness (Sinus Viscositatis).
But in August 2023, India became one of only four countries to have successfully landed on the moon when Chandrayaan-3 reached the moon’s South Pole. No other country had ever landed at the South Pole, a region thought to hold ice water and other valuable resources, so it was a win-win for India. That came just days after Russia’s Luna-25 crashed into the moon, also in an attempt to reach the South Pole.
South Pole: Beyond the comfort zone
Russia’s Luna-25 mission had aimed to land at the Boguslawsky Crater. The moon’s South Pole is thought to have deposits of ice water and possibly other resources necessary for any humans to live and work on the moon and return to Earth. It is a region worth investigating.
In 2014, researchers conducted a safety study of landing sites at the Boguslawsky Crater. They found slopes of 5-10 degrees and other, more dangerous, slopes of about 45 degrees, and “more than 16,000 boulders between [about] 0.5 meters up to 13 meters in size” in an area of 4 square kilometres.
So, there was fairly detailed information almost 10 years ahead of the mission. But as it came into land, the Russian space agency Roscosmos said its spacecraft “ceased to exist as a result of a collision with the surface of the moon”.
Moon hazards: Craters and boulders
A 2020 study put the number of known craters at close to 1,40,000, ranging from 1 (0.62 miles) to 8 kilometres in diameter, and others hundreds of kilometres in diameter, often incredibly steep. Then there are the boulders.
“[L]anding on the moon is still difficult. It requires deep experience in the lunar environment,” said Markus Landgraf, Senior System Architect and Moon Future Studies Team Lead at ESA’s European Space Research and Technology Center in the Netherlands. There are better maps available now, but nothing beats being there. Craters and boulders pose in-situ threats that need to be assessed as you attempt a soft landing—that is, surviving, not crashing, like Russia’s Luna-25.
Moon landings: Take nothing for granted
Our engineering and technology—“rocket science”, if you will—has developed in the 50-plus years since the Cold War space race, when Neil Armstrong and Buzz Aldrin became the first people to walk on the moon in 1969. And we have new players in space, more spacefaring nations, including India, with its Chandrayaan missions and regular satellite launches, and the UAE venturing to Mars. China has even landed on the far side of the moon.
But we have not seen the same level of technological improvement across the board, even with the advent of sustainable rockets. “Compared to the Apollo era, navigation technology is much more advanced today. Our on-board sensors allow for more precise and autonomous calculation of position and velocity, on-board computers are much faster, and advanced interfaces increase the situational awareness of ground and on-board crews alike,” Landgraf said.
Spaceflight is not only about computing power, however. “Rocket engine technology has advanced since the 1960s, mainly in terms of performance due to better materials and understanding of the hydrodynamics and combustion processes. But while computers are many times faster than 50 years ago, the efficiency of rocket engines has increased only by 10 to 20 per cent,” said Landgraf.
Moon rockets: We understand the risks better
Our technology has improved, as has our understanding of the risks—particularly those in actual rocket science. “In the 60s and 70s, we simply didn’t understand the risks we were taking. Today, we have a better handle on those, but to overcome them, we add complexity to the solution. But complexity makes it easier to miss a mistake and for ‘anomalies’ to occur,” said Malcolm Macdonald, a professor of spacecraft engineering at Strathclyde University, Scotland.
That is why we test rockets before we put people in them. We have learned from disasters such as the fire that broke out in the cabin of NASA’s Apollo 1 moon mission in 1967. “Modern spacecraft are far more complex [now], which both drives up the cost of development and testing, but also the risk of overlooking something,” said Macdonald.
The moon is back in our sights
After 50-plus years of seeming inaction, we are seeing a series of new moon missions but also a string of failures. In 2019, Israel attempted its first moon landing—Beresheet—and failed.
The same year, India’s Chandrayaan-2 attempted to reach the moon and land a probe called Vikram at the South Pole but failed. And in April 2023, Japan’s Hakuto-R also failed to land, apparently because it ran out of fuel. “The Hakuto-R and Chandrayaan-2 [failures] both originated—roughly speaking—from improper or incomprehensive testing campaigns, potentially caused by cost reduction measures,” Landgraf said.
But no one is giving up, and India’s successful soft landing at the South Pole will no doubt inspire other nations to lift their game.