The golden age of lunar exploration during the 1960s and 1970s was a time like no other. A space race was underway between the USA and the USSR, with each nation putting everything they could towards the fantastical goal of touching the moon. The pace of missions was incredible; if a Soviet spacecraft launched, the Americans would swiftly respond with their own mission just a month later, and vice versa. Every robotic mission to the moon brought about new revelations for scientists to comprehend, but in the end, only one nation would go on to make the leap from unmanned to manned expeditions.
The success of the USA's Apollo program brought about bold promises of permanent lunar colonies, which were to be operational by the late 1980s. However, these dreams of a sustained human presence on the moon would never materialize, with the American human landings ending in 1972, and the USSR’s lunar ambitions winding down after the launch of the Luna 24 sample return mission in 1976. A short break was in store for lunar exploration, at least that is what most people believed. However, nobody would imagine that it would be another 37 years until the next successful soft landing on the moon.
The success of the USA's Apollo program brought about bold promises of permanent lunar colonies, which were to be operational by the late 1980s. However, these dreams of a sustained human presence on the moon would never materialize, with the American human landings ending in 1972, and the USSR’s lunar ambitions winding down after the launch of the Luna 24 sample return mission in 1976. A short break was in store for lunar exploration, at least that is what most people believed. However, nobody would imagine that it would be another 37 years until the next successful soft landing on the moon.
Though the exploration of the moon faded from the limelight for a few decades, it is now undergoing a rapid resurgence, with a staggering number of entities, both governmental and commercial, expressing interest in gaining a slice of the lunar pie. Countries that have historically dominated spaceflight like Russia and the USA are now being challenged by newcomers like India and of course, China, which ended the 37 year-long lunar landing drought in 2013 with its Chang’e 3 mission. This new wave of lunar missions, both manned and unmanned, promises to be even more intense than the original space race, and the next decade could very well see exponential growth in trips to and from the moon. Although all of these missions are incredibly diverse in terms of design, goals, and scope, there is one thing that many of them share in common: the lunar south pole.
The lunar south pole is rapidly becoming the site of the first lunar gold rush, and how the region is utilized in the coming years will determine what the future of humanity’s presence on the moon will look like. However, to understand the rationale behind this newfound obsession with the south pole, we first need to look at the two major sources of motivation that are guiding companies and countries.
The goal of establishing permanent human outposts on the moon is the most obvious of the two motivations, as it has been in the works for decades. This is an endeavour that is largely being pursued by governments, but the final plans for colonization will likely rely heavily on private companies as well. Regardless of whether colonies are commercial or governmental, they will all require the basic resource of water, which has three main uses from a manned mission perspective: life support, rocket fuel, and radiation shielding. For humans to live, they will need water to drink, but unlike the ISS, which sources water from Earth, any future lunar colony will need to produce its own water since the moon is much further away. Additionally, the elemental composition of water also means that it will be critical to the production of rocket fuel since hydrogen and oxygen are highly efficient propellants. The final property of water that makes it essential to lunar colonies is its ability to block solar radiation and cosmic rays, which will ensure the long-term health of people living on the moon.
The second motivation that is guiding the future of lunar exploration, particularly when it comes to companies, is the prospect of mining. Although science fiction has popularized the extraction of rare earth metals and helium-3 from the moon, there is a much more important resource that the moon has in large quantities: water. Just as water will provide astronauts with rocket fuel to get home to Earth, it will also be necessary for even more ambitious missions into deep space. The general consensus among scientists is that expeditions beyond the moon to places like Mars will need refuelling stops, and there is no better place to refuel than the moon. At first glance, it might seem strange to refuel at a place so close to home, but it makes sense for a couple of reasons. Firstly, there are no other large bodies near Earth that could sustainably provide water for centuries to come. Secondly, spacecraft travelling to distant places would exhaust much of their fuel supplies while escaping from Earth’s gravitational field, so by the time they arrive at the moon, it would make sense to refuel. Therefore, establishing water mining operations and propellant production facilities on the lunar surface will be key to exploring places beyond the Earth-Moon system.
From these two scenarios of colonization and mining, it is clear that any future exploration of the moon will be constrained by water requirements, and this is where the lunar south pole becomes relevant.
For decades, scientists have suspected that the moon harbours vast reservoirs of water ice. The first evidence for these suspicions came from data that the Cassini spacecraft collected during a flyby of the moon in 1999, and a decade later, the Chandrayaan-1 mission observed the first direct evidence of ice deposits at the lunar poles. Missions that came afterwards corroborated the data, and it didn’t take long for scientists to identify the poles as the most promising location for lunar exploration.
Now, scientists know that although both the north and south poles of the moon contain large amounts of ice, the concentration is much greater at the south pole, which also has the added benefit of high insolation. In fact, certain areas in the south, like the rim of Shackleton crater, receive sunlight for more than 200 days straight!
The existence of ice in a region that receives large amounts of sunlight might seem like an unlikely combination, but there is a simple explanation. The lunar south pole is one of the more heavily cratered locations on the moon, and the presence of craters in sunlight means that there are also numerous permanently shadowed regions (PSRs), like the floor of the aforementioned Shackleton crater. While sunlit areas of the south pole experience temperatures above 100 degrees Celsius, NASA’s Lunar Reconnaissance Orbiter discovered that PSRs can dip as low as -248 degrees Celsius, which is easily cold enough for ice.
The discovery that ice is more abundant on the lunar south pole than previously theorized has fueled a new wave of scientific missions that have begun to pave the way for future development. One of the first was the LCROSS mission in 2009, which consisted of an impactor that deliberately crashed into the south pole and an orbiter that flew through the resulting debris plume. By analyzing the plume, scientists identified substances like ammonia, methane, and hydrogen, which as you know, is a component of water. More recently, the Chang’e 4 spacecraft carrying the Yutu-2 rover became the first mission to soft-land in the south pole region, and as of mid-2021, it is still operational. However, other countries and companies do not plan to leave Chang’e 4 alone for long, as additional landers and rovers are being planned to launch as soon as 2022.
One major venture that is currently in the planning stages is the US-led Artemis program, a commercial-governmental collaboration that involves numerous international partners like Canada and the European Space Agency. Artemis will start with the deployment of robotic spacecraft like the IM-2 mission, which is scheduled to land near the lunar south pole in December of 2022. Then, in 2023, China’s Yutu-2 rover will gain some mobile company in the form of NASA’s VIPER rover, which is being designed specifically for the exploration of PSRs. VIPER will have a drill to better understand the specific characteristics of lunar ice, and it will also be equipped with headlights that will illuminate ice deposits that have not seen sunlight for millions of years. These robotic missions will act as precursors to the ultimate goal of the Artemis program, which is to land humans on the lunar surface by 2024 (the feasibility of that deadline remains to be seen). The Artemis human landings are being planned for the south pole specifically because of the region’s potential for supporting a long-term human presence on the moon since the plan is to eventually establish a permanent base camp that will be able to rely on lunar ice as a primary source of water for life support, rocket fuel, and radiation shielding.
Separate from the Artemis program, Russia is also planning a revival of the Soviet-era Luna program in preparation for cosmonaut landings in the next decade. Next spring will see the launch of the Luna 25 lander, which will carry on the legacy of the original Luna line of spacecraft, with one key difference: unlike the previous 24 missions which targeted mid-latitude regions of the moon, Luna 25 will be heading to (you guessed it!) the south pole.
Finally, there’s China, which has come to dominate lunar surface exploration in this century so far. At least 3 more Chang’e missions are planned for this decade, and all of them will explore the south pole in one way or another. Possibly the most scientifically intriguing of these missions is Chang’e 6, which will be the first sample return mission from the south pole (to understand why sample return missions are so valuable, read our article on the Mars Sample Return Project).
The sheer number of missions in development right now might be reminiscent of the original space race, but this time, the race will have more than two contestants, and that fact alone means the chances of success are higher than ever before.
On Earth, gold rushes have marked periods of heightened development and innovation, so only time will tell if the same will occur on the moon in the coming years. The first lunar gold rush is undoubtedly underway, but this time, the gold will be icy, and the rush will take a new generation of spacecraft and their human companions to the lunar south pole.