In a few weeks, Nasa will celebrate a remarkable anniversary. Fifty years ago the last astronauts to visit the moon returned to Earth, leaving behind the final tell-tale signs that our species had once visited another world. For three days in December 1972, Apollo 17 crewmen Gene Cernan and Harrison “Jack” Schmitt explored the moon’s Taurus-Littrow valley, travelling over 30 kilometres in their lunar rover while collecting more than 100kg of rocks for return to Earth.
Then, on 14 December, geologist Schmitt returned to the mission’s lunar lander while Cernan gave a brief speech that was broadcast to Earth. “We shall return, with peace and hope for all mankind,” he pledged. Then Cernan closed the spaceship’s hatch and after adjusting the controls, placed his hand on the ship’s yellow ignition button and uttered the last words that a human would speak on the moon for the rest of the 20th century: “Okay, Jack, let’s get this mutha outta here.”
Their lander, Challenger, soared into lunar orbit and docked with the mission’s command ship, America. As Apollo 17 began its journey home, the astronauts held a televised press conference. It was not a global success. “Apparently we were already yesterday’s news because the networks didn’t find time to put us on the air,” recalled Cernan. Thus humanity turned its back on the last moonwalkers before they had even made it back to their home planet.
The world had been transfixed by Apollo 11 three years earlier. But after a series of further manned moon missions, boredom set in. Apollo 18, 19 and 20 were cancelled and Apollo 17 was decreed to be the last mission – although it seems this detail had slipped the US public’s attention by the time launch date arrived. When CBS cut its drama series Medical Center to show Apollo 17’s launch on 7 December, 1972, the network was bombarded with complaints while NBC – instead of showing Cernan’s final moon steps seven days later – chose to broadcast a repeat of the Johnny Carson show.
It was a humiliating end for the Apollo programme. For his part, Cernan – who died in 2017 – was bitter at this rejection by the public and fierce in expressing his disappointment that he had become the last person to walk on the moon. “It is a very dubious honour,” he told the Observer in 2002. “It tells us how much we have not done, rather than how much we have done.”
So it is ironic that the anniversary of the Apollo 17 landing will coincide with a mission that is intended to herald the return of human beings to the moon – albeit half a century later. Launched last week, Artemis 1 blasted an un-crewed Orion capsule on a 25-day mission beyond the orbit of the moon. It is scheduled to return to the Earth on 11 December, the exact date, 50 years earlier, when the Apollo 17 astronauts landed on Taurus-Littrow. If all goes well, and Orion’s systems perform as expected, a follow-up mission, Artemis 2, will put a crewed Orion capsule on course for a lunar fly-by in 2024 with Artemis 3 carrying out a crewed lunar landing the next year. According to this timetable humans will return to the moon after a gap of 53 years – though given the Artemis programme’s already troubled history of delays, the interval could be even longer.
After these flights, further missions will be launched with the aim of establishing Lunar Gateway, a crewed space station that will orbit the moon, as well as a permanent scientific outpost on the surface. Work will also begin on sending humans to Mars from the Moon. In addition, Nasa – in collaboration with space agencies in Europe, Japan and Canada – will initiate a host of robotic flights launched by a patchwork of nations and private companies. Missions will include landers and orbiters that will survey the moon for signs of water, mineral deposits and other features that will help prepare for future long duration missions.
These will include the Lunar Polar Exploration Mission, a robot spacecraft – designed jointly by the Indian and Japanese space agencies – which will drop a lunar rover that will explore the south pole region of the moon next year. In addition, Russia is planning a lunar return after a gap of 46 years with its Luna 25 mission which will investigate the composition of lunar soil.
Suddenly, everyone is going to the moon – though this grand return is not without controversy. Should we be placing heavy emphasis on putting humans on the moon? If so, how can we justify the heavy costs of lunar colonisation? Should we instead rely on robots to exploit its resources? And what role should private enterprise have in sending humans into space? These questions reveal major divides among scientists.
Those who believe we should rely on automated devices and landers and eschew human involvement include UK astronomer royal Martin Rees and US astronomer Donald Goldsmith. They point to the enormous cost of a single Artemis mission: around $2 billion. In addition, there is the price tag involved in keeping humans alive in space. “Astronauts need far more maintenance than robots, simply because their journeys and surface operations require air, water, food, living space, and protection against harmful radiation,” they state in their recent book The End of Astronauts: Why Robots are the Future of Exploration.
Others claim that sending humans back to the moon would be an act of inspiration. Without a big problem to overcome, we lose what it means to be human. Sending men and women back to the lunar surface would be reinvigorating for humanity. Again Rees and Goldsmith are dismissive. The Apollo missions were heroic events – for their time. Merely going back to the moon will simply look routine, despite the $90bn cost of the Artemis programme. Spend the money on other science, they argue.
But others disagree. The legacy of the Apollo missions – in particular Apollo 17 which spent the longest time on the moon – was immense, said planetary scientist Professor Ian Crawford, of Birkbeck College London. “Cernan and Schmitt travelled more than 30 kilometres over the moon surface in their rover. In comparison, robot rovers that we have sent to Mars take years to cover the same distances.
“The Apollo 17 astronauts returned more than 100kg of moon rocks. Robot craft have only returned tiny amounts in comparison. And the two of them drilled three metres into the lunar soil to get samples – something that robots have never achieved over the years – and deployed a wide range of geophysical experiments. Yet they were there for only three days. That shows you what humans can do. The Apollo programme laid the foundations for modern planetary science and we need to go back to the moon to build on what they started.”
Scientists like Crawford argue that building research stations such as those erected in Antarctica offer the best option for science. “These need not be occupied permanently, at least initially, but over short periods like many polar research centres. There is so much we can do on the moon but we need humans on site to maximise the scientific return. Eventually you might see these bases evolving into true colonies but that is not something that is likely to happen for perhaps a century.”
Many factors – not least financial ones – will clearly affect the rate at which the moon is opened up for human occupation and these will determine just how busy the moon will become in future decades. In his book, The Last Man on the Moon, Cernan recalls stopping as he took his final footsteps across the lifeless, airless surface towards the spaceship that would take him back to Earth. “I took a moment to kneel and with a single finger, scratched [my daughter] Tracy’s initials, TDC, in the lunar dust, knowing those three letters would remain there undisturbed for more years than anyone could imagine.”
It remains to be seen how much of the rest of the lunar surface will be touched or marked by humans this century. Will we soon be covering its plains and craters with evidence of our arrival. Or will the few marks in the soil, and the odd piece of abandoned Apollo kit, be the only evidence left to show our species once slipped the surly bonds of Earth and reached another world.