Reflecting on Apollo 11: 50 years since the first Moon landing
Astronomer Robert Massey looks back 50 years to when Neil Armstrong stepped out on to the surface of the Moon. Apollo 11 was the culmination of an enormous effort to send astronauts to our nearest neighbour and is one of the defining moments in twentieth century history. Apollo followed a long effort to understand the Moon from the ground, and is just one part of our continued journey to explore the universe around us.
Inspired by the anniversary, the art historian Alexandra Loske and I set out to understand how the Moon shaped our world, not just through its physical effects, but through culture – art, objects and fashion too. We turn 50 this year, so neither of us are young anymore, but we still have no memory of those earliest missions. Like Alexandra, growing up in the 1970s and 1980s, we watched the ambition for exploring space shrink back. In my case at least, science fiction dreams continued, which probably encouraged me to become an astronomer. But the prospect of people going any further than low Earth orbit – about 400 kilometres up, or roughly the distance from London to Newcastle – became remote.
Except on rare occasions like a total solar eclipse, the Moon is the only object in the sky where the human eye can see any detail, even without a telescope. It changes its shape over about four weeks, from a thin crescent to full, before reducing down and starting the cycle again. That, and the way it lights up an otherwise dark landscape, draws the attention of anyone who looks up. It isn’t surprising that the earliest peoples saw the Moon as a deity, marked its position with huge monuments like Stonehenge, and inscribed its image on to beautiful objects like the Bronze Age Nebra Sky Disk. Even today the Jewish and Islamic calendars are still based on the phases of the Moon, and the spring Full Moon determines the date of Easter.
Astronomy: from the naked eye to telescopes
The very best scientists, working in the ancient civilisations in Babylon and Greece, and the Islamic countries of the middle ages, relied on eyesight alone to study the sky. These researchers made accurate catalogues of the positions of stars, later used by European astronomers. But it took the invention of the telescope in 1608 by Dutch optician Hans Lippershey to begin to understand the real nature of the Moon, Sun, planets and stars.
By the following year astronomers across Europe were already pointing the new instruments at the sky. One of the first worked in west London. Thomas Harriot, a traveller and astronomer, set up a telescope in Syon Park near the River Thames. On the 26 July 1609, he looked at the Moon, making the first known drawing with an optical instrument. Harriot’s first sketches are rough, the result of a crude telescope, but improved quickly, and his later maps have the lighter and darker features familiar today.
Far better known for his huge contribution to science, working in northern Italy, Galileo Galilei made beautiful drawings of the lunar surface later in the same year. These early works showed the Moon to be a world in its own right, a place of smooth plains, mountain ranges, craters, ridges and channels, features we now associate with a violent history.
Astronomy is mostly a hands-off science. At the moment it would take our fastest spacecraft thousands of years to reach even the nearest stars, so we build up an idea of how they work by collecting light with telescopes of different kinds on Earth or in space. Unlike physics on the ground, or chemistry in a lab, we mostly can’t do experiments either, and have to watch things happen at a huge distance.
For 350 years that applied to the Moon too. The earliest lunar scientists relied on drawing skills, piecing together elaborate and detailed maps in a painstaking effort over many nights. Photography, used from the mid-19th century, offered another way to record that detail, and early science fiction writers like Jules Verne started to imagine the ways we could reach our nearest neighbour.
Many books show the Earth and Moon as almost adjacent. But although the Moon is about a quarter the size of the Earth, it is on average 380,000 kilometres away. 34 Earths could fit in the gap between us and the Moon – the distance is about 23 times as far as from London to Sydney. Any attempt to cross that, through the vacuum of space, was always going to be a challenge.
By the twentieth century, the nature of the Moon was becoming clearer, helped by amateur astronomers who made their own sketches and maps of its landscape. No one seriously believed there was life on its surface, and it was recognised as a virtually dead world without any kind of substantial atmosphere. Various theories explained the rugged lunar features, like volcanic activity, wrinkling of the surface as it cooled and the blasts resulting from meteorite impacts.
Copernicus crater. Credit: NASA
The development of rockets: from war into space
The same period saw a rapid development in rockets, in use as weapons since their invention in China in the 13th century. The Russian scientist Konstantin Tsiolkovsky and the German engineer Hermann Oberth separately developed models for rockets launching and moving through space, with Oberth thinking about exploring the solar system. American Robert Goddard simultaneously built the first liquid-fuelled rockets, eventually reaching an altitude of 2.7 kilometres.
Rocketry though has a chequered history. In the closing stages of World War Two, the German Nazi missile programme, led by Wernher von Braun, used V2 rockets to attack northern France and southern England. After the German surrender, American and Soviet leaders captured the engineers working on the V2 and used them to build their own long-range missiles.
From 1945, the ‘Cold War’ between the two post-war superpowers began, with rivalry between the United States and the Soviet Union at a high point in the 1950s. Both countries worked to build intercontinental ballistic missiles, rockets that could carry nuclear weapons to targets almost anywhere on Earth in less than an hour.
Von Braun (a problematic figure who benefited from the crimes of the Nazi regime) by then had a different and more peaceful vision. He pushed for rockets to enable the exploration of the Solar System, often referred to as the ‘conquest of space’, describing missions to the Moon and Mars.
The Space Race
It was though the Soviet successes that galvanised the US space programme. Under Sergei Korolev, an engineer whose existence was only announced at his death, Soviet scientists achieved a series of firsts. October 1957 saw the launch of the first satellite, Sputnik 1, that transmitted a beeping signal to the Earth, and intensified US fears of falling behind Soviet technology.
After some public failures (the USSR was less open about missions that didn’t succeed), the US launched its first satellite in January 1958. But by then the Soviets had put the first living being, a dog named Laika, into orbit. In 1959 their first probe to leave Earth orbit – Luna 1 – flew past the Moon, and later that year Luna 2 crashed into the surface, becoming the first terrestrial object to arrive at another world.
The surprising Far Side of the Moon
Studying the Moon from Earth has one major frustration. Captured rotation, where the Moon rotates on its axis in roughly the same time it takes to complete an orbit around the Earth, means that 41% of the surface is invisible from the ground. The far side, sometimes referred to as the ‘dark side’ (though it sees as much daylight as the side facing the Earth), was out of reach until the space age.
Luna 3, launched at the end of 1959, changed that. It sent back the first images of the far side, revealing a surprise. The landscape of the hemisphere facing away from the Earth is completely different to the one we see. Much more rugged, it is dominated by mountains and craters, and has very few of the lava plains seen as the ‘eyes’ and ‘mouth’ of the ‘Man in the Moon’ on the near side.
US robotic missions were initially less successful, with a number of failures to launch or reach their destination. In April 1961 the Soviet Union achieved another first, when cosmonaut Yuri Gagarin became the first person to orbit the Earth. Three weeks later the United States placed their own astronaut, Alan Shepard, in space, on a less impressive suborbital flight. Not until February 1962 did John Glenn match the Soviet achievement and become the first American to reach orbit.
JFK’s vision to land a man on the Moon
That January a new American President, John F. Kennedy, took office. In May 1961, acknowledging the Soviet head start in space exploration, he made a remarkable speech to both houses of the US Congress. With the words “…I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth” he asked his country to commit itself to a step forward in space exploration not seen since.
Shepherd, Glenn and five other astronauts flew in single person Mercury capsules. To reach the Moon needed larger spacecraft, the ability to separate and connect them together in space, and a far larger launch vehicle to carry them away from the Earth. Kennedy asked the newly-formed National Aeronautics and Space Administration (NASA) to accomplish all this, and reach the Moon, in just nine years.
Building a lunar spacecraft also meant NASA recruited a huge number of physicists, engineers and mathematicians. Described in the film ‘Hidden Figures’, it enabled women and black and minority ethnic Americans to take these jobs – rapidly changing the pattern of employment in the southern states notorious for racial segregation. The mathematics and coding work of two of the best known recruits, Katherine Johnson and Margaret Hamilton, was a vital part of the space programme.
From Apollo 1 …
After Mercury, the two astronaut Gemini space vehicles demonstrated that long duration flights were possible, and that people could work in space, outside their spacecraft. Then in 1967 came the first scheduled flight for Project Apollo, the spacecraft that would take astronauts to the Moon itself. Space veterans Gus Grissom and Ed White, with newcomer Roger Chaffee, were due to fly on Apollo 1 in February. But in a reminder of the risks of space travel, the three were killed in a test on the launch pad, when a disastrous fire consumed the interior of the capsule.
NASA quickly recovered from this tragedy. Apollo 7 took a crew to Earth orbit, and in December 1968 Apollo 8 made the first voyage to the Moon, taking astronauts away from Earth, and behind the far side for the first time. Famously the crew read from the Book of Genesis on Christmas Day, with a live television transmission, and photographed the Earth rising over the lunar surface.
The Earth and Moon as seen from Apollo 8. Credit: NASA
… to Apollo 11
By July 1969 everything was in place for Apollo 11, the first mission to place humans on the Moon. The huge Saturn V rocket, still one of the most powerful ever built, stood on the launchpad at Cape Kennedy in Florida. To reach the Moon needed three stages and an enormous quantity of fuel, and of the mission launch mass of 2.8 million kg, less than 6,000 kg would return to Earth.
Astronauts Neil Armstrong, Buzz Aldrin and Michael Collins made up the Apollo 11 crew, beginning their journey at 1332 GMT on 16 July. Three days later they arrived in lunar orbit. Armstrong and Aldrin entered the landing vehicle – the lunar module – the following day and prepared for the descent to the surface, leaving Collins behind in lunar orbit in the command module.
A lunar landing is anything but routine. On the way down, Armstrong and Aldrin saw alarms (partly a result of the onboard computer overloading), and were left with just 30 seconds of fuel by the time they touched down in the Sea of Tranquillity (actually one of the lava plains visible from Earth).
Apollo is a good example of where scientists took advantage of a programme put together for other reasons. The Apollo 11 crew and the ten astronauts that followed them collected 384 kg of Moon rocks, and left behind instruments like seismometers, that detected significant Moonquakes, and reflectors. Firing lasers from Earth at the latter and measuring the time for the reflected beam to return gives a direct measurement of the Earth-Moon distance, and confirms that the Moon is moving away at 3.8 cm a year.
Astronaut Buzz Aldrin, lunar module pilot, stands on the surface of the moon near the leg of the lunar module. Credit : NASA.
Apollos 12 to 17
There were a total of six successful landings, interrupted by the near tragedy of Apollo 13, where the crew needed all their resources and those of mission control to recover from an explosion in an oxygen tank two days after launch. Happily the astronauts made it back safely, but with the later Shuttle accidents and deaths it serves as a reminder that space travel is still a risky endeavour.
That first phase of human exploration ended with Apollo 17 in 1972, after which only robots have made the journey. Since 1990 Europe, China, Japan, India, Russia and the United States have all sent uncrewed spacecraft to the Moon. None of these quite compare to Apollo, but together they made major contributions to lunar science. Most recently, the Chinese rover Yutu 2 rolled off a lander to explore the far side of the Moon, exploring the region invisible from the Earth.
What did the Moon landings achieve?
Looking back half a century, it is reasonable to ask what Apollo and the subsequent missions achieved. At its height in 1966, the NASA budget accounted for nearly 5% of US national government spending. The agency today spends one tenth of that, and still delivers results that lead the world. An important difference today is that cooperation between NASA and other space agencies around the world shares not just the spending, but the scientific and engineering expertise.
In science terms, Apollo and its successors helped answer some of the long-standing questions about our nearest neighbour. For example, analysing rock samples from Apollo means we now think that the Moon formed after a colossal impact between the early Earth and a Mars-sized world, soon after the planets formed. Fairly soon after, the Moon condensed out of some of the debris, starting out about ten times closer to the cooling Earth than today.
Later robotic missions confirmed the presence of water ice on the Moon, a possible resource for a future lunar base, probably brought there by colliding asteroids and comets. This ice is mostly mixed in with lunar rock in craters at the south lunar pole, craters so deep that the Sun almost never reaches their base, and the ice stays frozen.
But for me the impact of Apollo is about what it meant for people back on Earth. An estimated 600 million people – one sixth of the global population at the time – watched the landing. It wasn’t just Americans who celebrated, but citizens of many different nations. Perhaps we need projects like this to unite humanity today.
When will we see a woman on the Moon?
50 years on, it looks as though there are finally serious plans to return to the Moon. European Space Agency (ESA) Director General Jan Woerner described a ‘Moon village’ in 2015. And this year American vice-president Mike Pence confirmed the US commitment to an international ‘Lunar Gateway’, a space station in lunar orbit that would be a base for exploring its surface. If this goes ahead, we could see astronauts in residence next to the Moon by the mid-2020s, and new landings - this time certainly including women - at the same time.
With UK involvement through ESA, this is a big opportunity for today’s physics students. For the first time in 50 years, graduates could get to work on a crewed Moon mission, designs for Moon bases, and instruments for lunar science and astronomy on the surface. I very much hope they take up that challenge.
In this illustration, NASA's Orion spacecraft approaches the Gateway in lunar orbit. Credit: NASA