Tristan Hotham

Researcher of campaigns and platforms. Maker of other things.

Junk on the Moon and Mars: every human-made object on two worlds, mapped

Title card reading 'Junk on the Moon and Mars' in red, black and rust on pale paper, beside two framed maps: a grey Moon scattered with coloured symbols for 133 objects, crowded in the middle of the near side, and an orange Mars with 27.

Since 1959 we have scattered 203.2 tonnes of hardware across the Moon and 10.4 tonnes across Mars: landers, rovers, crashed probes, spent rocket stages, six flags and a handful of golf balls. I mapped all of it.

Explore the interactive map
Read the paper

On 13 September 1959 a Soviet probe called Luna 2 hit the Moon, and the 9,100 kg rocket stage that had carried it crashed down nearby. Nothing made by people had touched another world before. Sixty-seven years later, Wikipedia’s list of artificial objects on the Moon has 104 rows, and its Mars list another 20. I turned those lists into one table, added the small things the Apollo astronauts left behind that the tables skip, and put the lot on maps of both worlds: 133 objects on the Moon and 27 on Mars.

Map of the whole Moon on a grey photographic base map, with coloured symbols for every human-made object: circles for landers, squares for rovers, crosses for crashes and impacts, diamonds for rocket stages and white stars for sites where Apollo crews left small items. Most symbols cluster in the middle of the near side; a few sit on the far side, including China's Chang'e 4 and Chang'e 6. A zoomed panel below shows the six Apollo landing sites with their stars, the Surveyor landers and the crash sites of the Saturn V third stages
Everything on the Moon. Colour shows who left it; symbol shows what it is. Labels sit beside the map, never on it.

Mostly American, mostly rockets

Add up the masses in the tables, counting each figure once, and you get 203,228 kg on the Moon. The United States left 58% of it, the Soviet Union and Russia 31%, and China, which only started landing in 2013, already 15.1 tonnes. A third of the whole lot is just five objects: the third stages of the Saturn V rockets from Apollo 13 to 17, each about 14 tonnes, which NASA deliberately crashed into the Moon for seismic research. Mars has about a twentieth as much, 10,380 kg, half of it American.

Two bar charts of mass by country. On the Moon the United States leads with 117.9 tonnes, then the Soviet Union and Russia with 63.5, China 15.1, India 3.3, Japan 3.0, and Europe and others a few hundred kilograms. On Mars the United States has 5.2 tonnes, the Soviet Union 3.1, China 1.5 and Europe 610 kg
Who left the most mass on each world. The two charts use different scales.
Bar chart of the twelve heaviest objects on another world. The top five are the Apollo 13 to 17 S-IVB rocket stages at about 13.5 to 14 tonnes each, followed by the Luna 2 third stage at 9.1 tonnes and a run of Soviet Luna spacecraft between 4 and 6 tonnes
The heaviest things humans have left on another world. All of them are on the Moon.

Two waves

The Moon’s junk arrived in two bursts. The space race brought 34 objects in the 1960s and 28 in the 1970s. Then, after the Soviet Luna 24 in 1976, nothing in the list reached the Moon until 1990. The second wave is now. The 2020s have already brought 20 objects from 7 countries, more than the 2000s and 2010s combined, and for the first time many of them are private: SpaceIL, ispace, Intuitive Machines, Firefly and others. Of the 9 company objects in the table, 3 landed in one piece.

Bar chart of objects arriving per decade, Moon and Mars side by side, coloured by type. The Moon has 44 in the 1960s and 46 in the 1970s, including many small Apollo items, none in the 1980s, a few in the 1990s, 2000s and 2010s, and 20 in the 2020s so far. Mars has none in the 1980s and between 3 and 8 in each other decade from the 1970s
Objects arriving per decade, Moon and Mars. The 1980s were empty.

Landing is hard. Mars is harder.

Wikipedia’s list of landings records 40 attempts at a soft landing on the Moon. 28 worked, 70%. China has a perfect four out of four; the Soviet Union and Russia managed 8 of 14, ending with Luna 25’s crash in 2023; commercial landers are at 3 of 6. On Mars 11 of 16 attempts worked. NASA landed 9 of its 10; the Soviet Mars 3 touched down in 1971 and fell silent almost at once; Europe’s Beagle 2 and Schiaparelli both failed; and China got Zhurong down first time in 2021.

Two bar charts of soft landing attempts and successes by country. Moon: United States 14 of 16, Soviet Union and Russia 8 of 14, China 4 of 4, Japan 1 of 3, India 1 of 2, Israel 0 of 1, 28 of 40 in all. Mars: United States 9 of 10, Soviet Union 1 of 3, Europe 0 of 2, China 1 of 1, 11 of 16 in all
Soft landing attempts that worked, by country.

The graveyard is quiet

Almost all of it is dead. Of the 104 rows in the Moon table, 68 hit the surface hard, by accident or on purpose, and only three are listed as still operating, all Chinese. On Mars, NASA’s Curiosity and Perseverance are still driving. The quiet survivors are the simplest things on the Moon: mirrors called retroreflectors, left by Apollo 11, 14 and 15 and carried by the Soviet Lunokhod rovers and India’s Chandrayaan-3, which still bounce laser pulses back to Earth so that the distance to the Moon can be measured.

Map of Mars on an orange topographic base map with every human-made object: blue circles and squares for NASA landers and rovers from Viking 1 and 2 to Curiosity and Perseverance, red symbols for the Soviet Mars 2, 3 and 6, a teal circle for Beagle 2 and a teal cross for Schiaparelli, a gold circle and square for China's Tianwen-1 and Zhurong, and white stars for smaller pieces such as heat shields and pennants
Everything on Mars. The positions of Mars 2, 3 and 6 and Mars Polar Lander are estimates.

Flags, golf balls and a Fallen Astronaut

The tables skip the small stuff, so I added 29 items that Wikipedia’s articles name. Six American flags, five of them still standing, according to pictures from orbit; Apollo 11’s was blown over by the engine on take-off. A plaque on the ladder of each Lunar Module. The golf balls Alan Shepard hit on Apollo 14. A Bible left by David Scott, and the Fallen Astronaut, an 8.9 cm aluminium figure he laid beside a plaque naming 14 astronauts and cosmonauts who had died. And a small vial of the ashes of the lunar scientist Eugene Shoemaker, which rode Lunar Prospector into a crater near the south pole in 1999: the only human remains on the Moon.

How I did this

Everything comes from English Wikipedia: the lists of artificial objects on the Moon and on Mars, the list of landings on extraterrestrial bodies, and the articles on the Moon landings, the Fallen Astronaut, the Apollo science packages and the lunar rover. I parsed the tables cell by cell, counted shared or repeated masses once, converted Martian longitudes to one convention, and kept objects without a known position off the map rather than guessing. The small items are placed at their landing sites, so their positions are approximate. The two Wikipedia lists disagree on where 8 objects are, by more than a degree; I kept the object tables’ positions. The paper sets out every step and caveat.

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Read the paper
Data and code

Notes and sources

Tristan Hotham

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