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[[{"type":"media","view_mode":"media_large","fid":"39597","attributes":{"class":"media-image","typeof":"foaf:Image","style":"","alt":"The Smell of Space"}}]]When we think of space, we think of beautiful pictures of bursting stars, colorful planets and never-ending darkness. We think of the loud noise rockets make when they BLAST off into the sky. We can imagine what it would feel like to float and tumble through zero gravity. If we think long enough, we can nearly taste the dryness of an astronaut’s dehydrated food. But does anyone know what space smells like? To find out, we went to our Extraordinary-Scientist-in-Residence, former NASA astronaut Dr. David Wolf.
The "smell of space" is how Astronauts refer to a hard to describe odor we perceive after spacewalks. The technical term for a spacewalk is "extravehicular activity," or "EVA." To me it is something between a sensation and an odor a little like near a swimming pool. It is not unpleasant at all, and not very strong, but there is no odor quite like it on Earth that I know of.
While working "outside" in our spacesuits, with our closed life support systems, we do not detect this smell. But when we open the airlock to return back inside the spacecraft the other Astronauts inside immediately notice it as do the space-walkers after removing their helmets. I have found this same smell on the International Space Station, the Russian MIR Station, and the Space Shuttle. It only lasts about an hour because the air purification systems of our spacecraft are so effective at scrubbing molecules from the air. So effective that spacecraft are mostly devoid of odors. When we land back on Earth, I am always amazed at how powerful the "Earth" odors are, like grass near the runway.
In this picture I am coming in (ingressing) the International Space Station airlock in 2009, during the STS-127 ISS assembly mission. I'm surrounded by tools and equipment that were used for space station assembly.
We really don't know the source of "the smell of space." It could be on on our spacesuits and tools or even be trace molecules from the vacuum of space that come in with us through the airlock, as our noses are amazingly sensitive. It does seem to me that spacesuits that have been used multiple times retain a faint remnant of this mysterious odor. I have also noticed it after docking two spacecraft together such as the Space Shuttle and the International Space Station. When we open the hatches between the vehicles a little "space" gets in and we detect "the smell of space." I have to wonder if the Apollo astronauts also found this on the Moon! It's one of the unsolved little mysteries of spaceflight.
Another hypothesis recently reported in Mental Floss is that the smell comes from “polycyclic aromatic hydrocarbons (PAHs), which are compounds produced when stars and planets form.” If you’d like to get a whiff of these compounds, fire up your grill. According to Mental Floss, PAHs are also produced when we barbecue.
