"A bit charcoal-esque with hints of eggy sulphur? No idea actually considering the Apollo crews said 'spent gunpowder' but the composition on the Moon is mainly silicon with some iron". Dr Louisa Preston, Dept of Space & Climate Physics at University College London, and Planetary Groups' Habitability Lab at the Mullard Space Science Laboratory.
We have an idea of what Moon dust smells like, thanks to the Apollo Astronauts that visited our satellite. During moonwalks, Moon dust particles clang onto the space suits, gloves and boots of astronauts. After returning to the safety of the lunar module and taking off their helmets, moonwalkers noticed the smell of this dust.
Astronaut Gene Cernan, who was the last man to walk on the Moon, said that Moon dust smelled like spent gunpowder, and remarked "smells like someone just fired a carbine in here." Charlie Duke, Apollo 16 pilot, said "it is really a strong smell, … It has that taste -- to me, [of] gunpowder -- and the smell of gunpowder, too."
However, it’s important to understand that Moon dust is nothing like gun powder! According to NASA, “almost half is silicon dioxide glass created by meteoroids hitting the moon. These impacts, which have been going on for billions of years, fuse topsoil into glass and shatter the same into tiny pieces. Moondust is also rich in iron, calcium and magnesium bound up in minerals such as olivine and pyroxene.”
Nobody knows for sure why the Apollo astronauts smelled spent gunpowder. There are several theories, including:
Moon dust reacting with moist air in the lunar module and the moisture releasing volatile smelly molecules into the air.
Solar wind ions getting caught in the dust and evaporating when in contact with air inside the spacecraft.
Moon dust beginning to oxidise when coming into contact oxygen in the lunar module for the first time, and causing a burning smell.
The interesting thing is that the dust doesn’t smell here on Earth, so whatever causes the smell, it happens when ancient Moon dust first encounters the warm and moist air inside the lunar module.
How do we know so much about the Moon?
Thanks in part to amazing technology put to good use in Lunar space missions, and in part to the bravery and curiosity of the Apollo missions’ astronauts, who not only walked on the Moon, but also brought with them 382 kg of Moon rocks! Over the past few decades, scientists around the world have studied the Moon rock samples, which together with data from other missions to the Moon, like the SMART-1, Chandrayaan-1 and Lunar Reconnaissance Orbiter (LRO), have given us a very good idea of what the Moon is made of, and therefore, of how it might smell if we’d be able to breathe on its surface.
We created two different smells for the Moon.
The first smell was based solely on the Apollo astronauts’ descriptions and used a traditional way of capturing fragrance called enfleurage that uses cold fat to absorb aromatic molecules from the air. We set up to create an enfleurage extract of gunpowder smoke in an attempt to produce a faithful recreation of the smell reported by moonwalkers.
We then designed a second Moon-smell using perfumery ingredients that combine the smell of spent gunpowder with a more realistic smell of what the minerals found on the Moon might smell like, and the sensation of very fine moon dust tickling your nostrils as you inhale. We thought about the dry, dusty and mineral notes of the major chemical elements in the upper lunar crust (O, Si, Al, Ca, Fe, Mg, Ti), the extreme dryness due to lack of water, and the main minerals found on the Moon: plagioclase, pyroxene, olivine and ilmenite. The resulting smell is dusty, mineral and cool, and if it had a colour, it would be grey and remind you of a grey dry volcanic rock. We combined both, the smell of gunpowder and the smell of minerals and dust, to create the final Moon-smell for our educational and outreach activities.
Read more about the smell of the Moon HERE.
MORE ABOUT THE MOON
12 astronauts walked on the Moon during the Apollo programme (1969 – 1972)
Average distance from Earth: 384,400 km
Orbit and rotation period: 27.3 Earth Days
Equatorial radius: 1,737.5 km
Mass: 0.0123 of Earth's
Surface gravity: 1.62 m/s2
Mean density: 3.34 kg/cm3
Escape velocity: 2.38 km/s
Surface temperature range: -233 to 123 °C
The Moon has no atmosphere so the lunar surface is unprotected from solar winds, cosmic rays and meteorites. This also means that no sound can be heard on the Moon!
Major chemical elements in the upper lunar crust: O, Si, Al, Ca, Fe, Mg, Ti. The moon is depleted in water and volatile elements such as Na and K, which are only found in very small quantities. Other chemical elements are present in tiny amounts of parts per thousand or even parts per million.
Main lunar rock forming minerals: plagioclase, pyroxene, olivine and ilmenite .
Learn more about the Moon with the European Space Agency HERE
Learn more about the next crewed missions to the Moon, the Artemis missions. NASA will land the first woman and first person of color on the Moon, and, in time, establish the first long-term presence on the Moon. More information from NASA HERE
