Space, the final frontier…vastness we can only observe when we look up at the night sky from our humble planet dwelling. But what exactly is space? If you ignore the galaxies with all their planets and stars, then the huge area of nothingness in-between is mainly a vacuum. No particles at all, nothing, just emptiness. And if there are no particles, then there can be no smell, right?

After all, our noses work by being sensitive to microscopic molecules that drift through the air and get trapped on a film of mucus in the back of your nose. Then 40 million special receptor cells fire signals to different regions of the brain and…voila! You have the sensation of smell. But then many astronauts have come back to tell us that space has a particular smell; that there is a whiff, to the cosmos. We’ll find out more about it today, in this of The Infographics Show: What Does Space Smell Like?

Astronauts typically stay on the international space station for 6 months. So imagine all that food waste and dirty socks. With no regular cleaning service, there’s bound to be a few bad smells floating about. But after doing a little online research to see what these intergalactic travellers are reporting back, it seems there’s more adrift than a bad case of dirty laundry.

According to Tim Peake, a UK astronaut, the smell of space can be likened to a summer barbeque, burning hot dogs on a charcoal grill. Peake describes the aroma of space in his book, Ask an Astronaut. He says it’s his favorite question but the hardest to answer because exactly what it smells like is hard to put your nose on. And Peake has been to space and smelt the empty aroma, on a number of occasions. The first time he was aware of the whiff, was after being on the space station for a few days.

He was helping 2 astronauts back into the capsule after their spacewalk. So for Peake, it was a reminder of back home – a good old British barbeque.

Astronauts have described it as many things including seared steak, hot metal, and even welding fumes. Three-time spacewalker and American astronaut Thomas Jones said it carries a distinct odor of ozone, a faint acrid smell and a little like gunpowder. It is sulfurous, he said. Through our research, we found there are actually numerous accounts of the onerous odor.

Very few astronauts do not have an opinion. Many mention sharp metallic types of smells or burnt meaty smells. After a mission in 2003, American astronaut Don Pettit described on the NASA blog what he smelt. He said the best description he could come up with was metallic, a rather pleasant sweet metallic sensation. He said it reminded him of college summers when he worked for long hours with an arc welding torch repairing heavy equipment. The smell was like those sweet smelling welding fumes.

So do these astronauts have super sensitive noses able to pick up the odor from a particleless void, or is something else at play?

We wanted to see if we could work out where these suspect smells are coming from. There is no way to actually directly smell space as whenever an astronaut is exposed to the void, he or she is protected within a space suit, breathing oxygen from a tank.

So in all cases, the experience of the smell comes from items that have been exposed to space and then come back into the ship. In an article the Atlantic ran, about the smell of space, they referenced research stating that the aroma is the result of high-energy vibrations in particles brought back inside which mix with the air. Well, we know there must be some particles in the mix, but what is the actual smell?

Louis Allamandola, the founder and director of the Astrophysics and Astrochemistry Lab at NASA Ames Research Center, has a theory. The report of hot metal, diesel fumes and barbecue or meaty smells, are mostly the cells of dying stars. The by-products of all the combustion are smells from compounds called polycyclic aromatic hydrocarbons. These molecules maybe all over the universe, floating around indefinitely. They appear in comets, meteors and space dust. When astronauts are outside the space station, the compounds stick to their suits and so can be picked up as a smell when back on the station. So who would have imagined we can smell the stars!

In 2008 The Daily Telegraph reported that Nasa commissioned Steven Pearce, a chemist and managing director of fragrance manufacturing company Omega Ingredients, to recreate the smell of space in a laboratory.

Pearce came to NASA’s attention after he recreated the smell of The Soviet Mir space station as part of an art installation on Impossible Smells. The Mir burnt up in the atmosphere in 2001. Other recreations by Pearce included recreating the metallic fallout of the first atomic bomb, the aroma of cloves and oranges, and even the first aid kit of a medieval plague doctor.

The result of Pearce’s efforts? Unfortunately he didn’t complete the task so it seems the true smell of space will need to stay well out there, beyond the final frontier.

What we can tell from the stories of our astronauts is that space smells like everything from seared steak, or British barbecued sausages, to metal being welded or even gunpowder. And though there is nothing to truly breathe in a vacuum, the combination of dead stars, galactic dust clouds, and a bit of old commit, can create a smell that traverses even the vastness of space…Is there anybody out there? We are still yet to discover, but one thing we now know for sure, is that if there is, then an astronaut will pick up the aroma.

So, what do you think about the smell of space? Do you have your own theory about where the strange smell is coming from? Let us know in the comments. Also, be sure to check out our other article called NASA vs SpaceX!


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