The Scents of Infinity: What does space smell like?13th Jun 2023
Our planet is a unique ecosystem with millions of scents, and our sense of smell gives us the opportunity to experience this incredible range. But what does space smell like? Theoretically, there are no smells in a vacuum environment of space, but the astronauts’ practical experience and astronomical studies prove the opposite.
Years of space exploration and observation allow us to conclude that any space object, as well as the space between objects, can have its own smells. They depend on the chemical composition of the object and the processes occurring on it and around it.
Conducting research using the 30-meter IRAM radio telescope in the Milky Way, German scientists from the Max Planck Institute suggested what the centre of the universe smells like. You will be surprised, but it is delicious! It smells of rum and raspberries. Astronomers have looked for signs of life in cosmic dust and gas clusters, but no protein molecules have been found. Instead, ethyl formate molecules were discovered in the gas clouds of the universe; this substance creates the fragrance of forest raspberries and rum. But this is still only a a hypothesis.
Yes and no. The senses of astronauts in space work in the same way as they do on Earth. But it is impossible to feel the scent of the universe by going out into outer space. First, there is no air; space is almost a vacuum, which means that odour molecules do not spread in space the same way they do in our atmosphere. Second, an astronaut cannot take his spacesuit off and sniff the space environment — he will instantly die. So you can only find out what outer space smell like inside the spacecraft or on the ISS. But how does that happen?
When astronauts go into outer space, odours settle on the outer surface of their spacesuits, and the sense of smell catches them when the astronauts go back inside.
When asked does space have a smell, Discovery shuttle pilot Tony Antonelli says it definitely does, and it’s “different from everything else.” Mission Specialist and veteran of the four STS missions Thomas Jones believes space “has a distinct smell of ozone, a faint acrid smell… a bit like gunpowder, sulphurous”. And Don Pettit claims that he sensed the odour every time he closed the airlock behind his returning colleagues, and the scent came “from the air ducts that squeezed the compartment. Then I noticed that this smell was on their suit, helmet, gloves and tools. It was more pronounced on fabrics than on metal or plastic surfaces”.
However, the astronaut found it difficult to say what exactly the space smells could be compared to. In his opinion, they are not like any common food or anything else we’re used to. Rather, the smell of space gives a sugary, metallic taste reminiscent of the sensations received from a working welding machine.
Astronauts of the Australian Academy of Sciences also compare the scent of space with the smell of welding smoke. In addition, they thought the odour was reminiscent of “burning metal,” “the smell of ozone,” “walnuts and brake pads,” “gunpowder,” and even “burnt macaroons.” Let’s find out where such a wealth of flavours comes from.
According to Canadian astronaut Chris Hadfield, the scent of gunpowder and sulphur is not present in space but is formed as a result of a reaction when “the vacuum of space sucks chemicals out of the spacecraft walls.”
Scientists believe that an astronaut in a spacesuit brings atomic oxygen into the ship, and when the pressure is re-pressurized, these atoms combine with oxygen and turn into ozone, which, in turn, gives a metallic space smell and other strange odours.
If the scent of heated metal, gunpowder, and ozone in space is not very surprising, then the origin of the fried meat odour is intriguing. Why does space smell like steak? The reason lies in the polycyclic aromatic hydrocarbons found in any part of the universe. Louis Allamandola, a professor at the Ames Research Center, explained their origin this way: “They are present in space in large numbers, emerging from comets, meteorites and cosmic dust.”
There are also such smells on Earth, and not only from barbecue. According to the scientist, molecules of aromatic hydrocarbons on our planet are found in coal, oil, and some food products. Many astronauts say that space smells like burnt steak. And since the association is the same for everyone, this opinion can be trusted.
What does it smell like on the space station?
Astronauts live on the ISS for several months, and naturally, this space is filled with different odours. Astronaut Thomas Jones shares that space on the ISS smells of sulphur and gunpowder and has “a distinct smell of ozone, faint and acrid,” as in the above-mentioned situations when the scents were brought into the ship on a spacesuit. But other odours are added to those.
ESA astronaut Scott Kelly says that these are the smells of unwashed body, antiseptic, and rubbish. And chemist Steve Pearce, the founder of food flavouring company Omega Ingredients, showed the scents of the Mir space station (the predecessor of ISS) in the Impossible Smells art installation: a mixture of stale body odours and sweaty feet, petrol, and nail polish remover.
Why does the inside of space stations have such an unpleasant air? The answer lies in the conditions under which astronauts operate:
- the presence of odours in the ship equipment;
- astronauts’ regular physical exercises, as a result of which sweat is released;
- lack of water for washing;
- inability to change linens frequently;
- clothes are not washed but stored.
In other words, spaceship conditions are spartan, and one can’t open a window to ventilate, whereas in-built ventilation works at peak capacity.
What do other planets smell like?
NASA chemist Dr Luis Allamandola believes that the scents of space are different in different parts of the universe. The smell of space depends on the molecules and their combinations at a given place. However, due to the lack of oxygen and the abundance of carbon, almost all odours will be unpleasant, hydrogen-sulphuric.
The Moon is the only object in space that astronauts have been able to sniff. Apollo 17 mission member Gene Cernan reported that the lunar dust delivered aboard the lander smelled like fired gunpowder. The scent was caused by the combination of hydrogen and helium ions with silicon dioxide in the Moon’s soil.
The atmosphere of Mars is practically odourless, but you will still scent sulphur, similar to the odour of a burnt match, and, of course, you will sense the smell of hydrogen sulphide, which we associate with rotten eggs. Mars also has a special taste. What does it smell and taste like on Mars? It is the scent and taste of rust due to oxidized iron in the dust of the Red Planet.
Venus is also interesting from the point of view of odours. Under the influence of enormous temperatures, clouds of sulphuric acid that cover the atmosphere of carbon dioxide exude a sour, pungent odour. The scent of phosphine, reminiscent of the rotten fish odour, is added to it; and one can also sense hydrogen sulphide and sulphur dioxide with the aroma of a smouldering match.
The scent of phosphine and ammonia is added to the smell of hydrogen sulphide on the gas giant Jupiter. This mixture is very unpleasant. Clouds of hydrogen cyanide, sometimes found on Jupiter, have a slightly different odour. Saturn smells almost the same but has an even richer ammonia scent, and the concentration of ammonium sulfate adds an odour similar to hair dye.
As you can see, each celestial body has its own special scent, but there are also similarities. If you are wondering what Neptune or any other planet smell like, then it will definitely have a smell of hydrogen sulphide, and there will also be impurities of other odours to varying degrees.
By the way, you may not only imagine but actually feel the smell of space. To do this, it is not at all necessary to become a part of the astronaut corps. In 2020, NASA and Steve Pearce developed fragrances called Eau de Space and Smell of the Moon, and now everyone can experience them for only $100. It’s incredible!
Summing it up
So what does space smell like? Scientific research and astronauts’ experience say that space smells in different ways, but mostly, not very pleasant. But after all, there are enough fragrances on Earth that make us wrinkle our noses. One thing is certain — we will need to go much further than the Moon to find out what new space discoveries smell like.