You might have thought about the stunning and unparalleled views from outer space – or even the eerie silence of the vacuum – but what you may never have considered is space’s distinct smell.
Those who know best – the astronauts who have actually been up there – have described space as having a distinct odor.
To be clear, nobody has smelt the near-perfect vacuum of space directly and lived to report back on its olfactory notes.
Astronauts are, however, able to report back on a unique scent that lingers on their space suits upon removing their protective helmet once safely back beyond the airlock doors of ISS or another craft.
While this faint and indirect aroma doesn’t allow them to report back on precise top and base notes – the smell of space is said to be a complex one.
“It is hard to describe this smell; it is definitely not the olfactory equivalent to describing the palette sensations of some new food as ‘tastes like chicken’,” NASA astronaut, Don Pettit, told Space.com.
He had just returned from a mission in 2003.
“The best description I can come up with is metallic; a rather pleasant sweet metallic sensation.
“It reminded me of my college summers where I labored for many hours with an arc welding torch repairing heavy equipment for a small logging outfit.
“It reminded me of pleasant sweet smelling welding fumes. That is the smell of space.”
Meanwhile, former NASA astronaut, Thomas Jones, compared the odor to ozone.
Biochemist and CEO of Omega Ingredients, Steve Pearce, combed through astronaut interviews to help him craft a NASA-commissioned scent.
Overall, astronauts often compare the smell of space to “hot metal, burnt meat, burnt cakes, spent gunpowder and welding of metal,” he said.
It’s thought the metallic note may come from high-energy vibrations of ions.
However, another theory suggests that oxidation could be behind it.
When astronauts come back to their spaceship and the airlock re-pressurizes, a chemical reaction occurs, according to How Stuff Works.
Oxygen atoms in space attach to their suits and mix with the atmosphere on the spacecraft.
Oxygen atoms combining to form atmospheric oxygen (O2), could cause the smoky, charred odor.
It’s like the smell of combustion, without the flames and smoke.
Then, there’s a theory which revolves around stellar explosions over the billions of years the universe has existed.
When stars go out, they do so with a bang.
In doing so they create compounds called ‘polycyclic aromatic hydrocarbons’ (PAHs).
These PAHs exist on earth in coal, tobacco and the food we eat – and so could be behind the burnt note.