It is a question that has long puzzled earthbound scientists - what does space actually smell of?
Thanks to an orbiting astronaut, we now know the answer, and it is even stranger than you might expect.
Astronauts say the unique smell aboard the International Space Station is reminiscent of two things - meat and metal.
It has been described as like 'seared steak', 'hot metal' and welding fumes'. Astronaut's have largely agreed on the scent.
Tony Antonelli has said, "definitely has a smell that's different than anything else."
Three-time spacewalker Thomas Jones said returning to the ISS, 'carries a distinct odor of ozone, a faint acrid smell.' and is 'sulfurous'.
Nasa is now trying to reproduce that smell for training purposes, and has hired the scent chemist Steve Pearce to recreate it on earth, according to The Atlantic. Part of his inspiration is a description from astronaut Don Pettit.
'Each time, when I repressed the airlock, opened the hatch and welcomed two tired workers inside, a peculiar odor tickled my olfactory senses,' Pettit said.
At first I couldn't quite place it. It must have come from the air ducts that re-pressed 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, he admits it is hard to pin down the exact smell of space.
'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.'
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.'