The smell of space is quite complicated to define, as we are unable to inhale it without we being harmed or die from the harsh conditions there. You can read about these conditions HERE.
About the general scent
Just as the smell of food and cigarettes lingers on our clothes for a while, during spacewalks, the smell of molecules found outside also soaks into our spacesuits to some extent. Returning to the airlock after a spacewalk, astronauts report that they smell characteristic smells after removing their helmets.
Greg Chamitoff (USA, August 6, 1962 – ), American electrical engineer and former NASA astronaut, said: “Here’s one smell up here that’s really unique though… we just call it the smell of space. There’s this really, really strong metallic smell and I don’t know exactly what it is.”
Alexander Gerst (Germany, May 3, 1976 – ), German geophysicist and ESA astronaut, stated the following: “To me, space smells like a mixture between walnuts and the brake pads of my motorbike.”
Donald Roy Pettit (Silverton, Oregon, April 20, 1955 – ), American chemical engineer and astronaut, defines the smell of space as the pleasant, sweet smell of welding fumes.
Other descriptions include: burning metal, a strange ozone smell, a sour smell, gunpowder, burnt almond cookie, burnt meat.
Based on the above, it can be said that space as a whole is characterized by a kind of “sooty”, burnt smell for most astronauts. There are several explanation for this.
Chemistry
One theory is that oxygen atoms in space stick to astronauts’ suits during spacewalks, and when they return to the airlock, a chemical reaction of oxidation occurs during the repressurization (increasing air pressure). Additionally, some oxygen atoms can form ozone, O3. This process is similar to flameless, smokeless combustion and has a similar odor, which may explain the smoky, charred odor.
Dr. Louis Allamandola, former director of NASA Ames Research Center – Astrophysics and Astrochemistry Laboratory, believes it is most likely that so – called polycyclic aromatic hydrocarbons (PAHs) are what cause this characteristic smell. These molecules are common throughout the universe. Here on Earth, they are also found in things like soot, exhaust fumes, and charred meat.
At the same time, he mentions that it is not all the same where we “smell” space. We have to think in two regions. One is interstellar space itself. As stars reach the end of their lives, the elements created by fusion are expelled from them. For example, carbon, nitrogen, oxygen. Some stars produce more carbon than oxygen at this time and form soot. Carbon – rich stars can produce so much soot that it can blocks their light until this soot cloud, or nebula, clears.
This is most comparable to the burning of fossil fuels, such as a car with a running engine and little oxygen, which starts to soot from the exhaust, emitting black smoke, with a characteristic, burnt smell. But the scent could be very similar also a smell of burnt meat, burnt bread crumbs in a toaster.
Polycyclic aromatic hydrocarbons are extremely complex molecules and stable, mainly formed as by – products of the combustion of organic materials.
It’s pretty much the only molecule that survives interstellar radiation and massive shock waves, so it floats out there for a very long time.
The other region is found in the dark bands and patches of the Milky Way. When large amounts of soot and other dusty materials formed at the end of the lives of stars accumulate, they form dark bands and patches over vast areas. These are interstellar dust clouds that are so huge that they block the light of the stars behind them, and they are only 15 degrees warmer than absolute zero, or about −258.15 C°. The atoms and molecules floating here cool down so much that they freeze onto the grains, forming new molecules. However, there are regions in these clouds where UV is strong enough to chemically affect the frozen parts. These are mainly composed of water, alcohol, ammonia, carbon dioxide, carbon monoxide, PAH, formaldehyde, for example. Comets, moons, and young planets can be born from this type of ice.
So in these clouds, we could feel like we were in an ice cream parlor and an autopsy room at the same time, based on the smells that appear there.
Space perfumes?
NASA isn’t just treating these experiences as a curiosity. In 2008, the agency commissioned Steven Pearce, a chemist at Omega Ingredients (a company that specializes in scents and flavors), to create space smells for astronaut training simulations. This is important so that they can distinguish between, say, a chemical leak on board a spacecraft or space station and odors “brought in” from space.
During the Apollo Program, astronauts often smelled a gunpowder – like odor after climbing back into the airlock of their lunar module from the surface of the Moon, taking off their helmets. This described smell was also created by Pearce:
“ Recently we did the smell of the Moon! Astronauts compared it to spent gunpowder.”
So now, astronauts are embarking on their missions with some gudiance and even the world of perfumes has grown with 2 otherworldly scents (tap on the pictures).
Smell of Objects
Sagittarius B2
This dust cloud is located in the middle of the Milky Way. In addition to containing various types of alcohol, the concentration of ethyl formate is high. The latter gives the smell of raspberries or rum here on Earth, for example.
Io, a moon of Jupiter
Scott Sandford, a lead researcher at Ames, describes it this way: “Io is an environment that probably has its own unique smell, I suspect strong overtones of rotten eggs.”
Titan, Saturn’s largest moon
Titan has an atmosphere that contains a thick haze of hydrocarbons. On its surface, liquid hydrocarbons form oily lakes and rivers, but methane, Titan’s dominant hydrocarbon, has no smell. Yet if you could breathe in its atmosphere, you would smell gasoline. So what’s that like?
NASA’s Cassini spacecraft has identified an unknown chemical in its atmosphere that NASA’s ground-based laboratory experiments have determined is a molecule containing nitrogen, methane, and benzene, which belongs to a family of molecules called polycyclic aromatic nitrogen heterocycles (PANH). Gasoline is made from crude oil rich in hydrocarbons, which are molecules made of hydrogen and carbon atoms, such as methane and ethane.
Comet 67P/Churyumov–Gerasimenko
The mission of the ESA – European Space Agency Rosetta probe was to study the comet, including a lander. In 2014, when it caught up with the comet, it also examined its coma. Among the molecules in the coma, it identified hydrogen sulfide, ammonia, hydrogen cyanide, carbon sulfide and formaldehyde. For example, hydrogen sulfide can be compared to a rotten egg, ammonia is like urine, hydrogen cyanide has the smell of almonds, carbon sulfide is sweet, and formaldehyde is sour.
The coma of comets consists mainly of water vapor and carbon dioxide, so if we could smell it, it would be quite weak.
Be a Nerdy Bird!
