What Does Outer Space Smell Like? A Whiff of the Universe’s Secrets

Outer space, often depicted as a silent and sterile void, harbors a surprisingly rich tapestry of scents, at least for those who venture beyond Earth’s atmosphere. Astronauts returning from spacewalks have consistently reported a distinctive odor upon re-entering their spacecraft. Descriptions range from “burnt steak” and “hot metal” to “welding fumes” and “spent gunpowder” 

These scents are not the result of actual smells in the vacuum of space, since molecules are too sparse to carry odor, but rather chemical reactions occurring when astronauts re-enter the pressurized environment of their spacecraft. One prevailing theory suggests that atomic oxygen, which clings to spacesuits during spacewalks, reacts with the oxygen inside the spacecraft to form ozone, producing that characteristic burnt aroma.

Interestingly, the universe’s diverse celestial bodies emit their own unique odors. For instance, Jupiter’s upper clouds, composed of ammonia ice, are likened to the smell of cat urine, while deeper layers might emit a stench reminiscent of rotting eggs due to ammonium sulfide. Comets, planets, and gas clouds each have their own distinct scents, offering a fragrant glimpse into the cosmos’ chemical makeup.

To bring these cosmic aromas closer to Earth, scientists and fragrance designers have endeavored to recreate them. For example, the fragrance “Eau de Space” was developed to mimic the scent of outer space, blending notes of gunpowder, seared steak, raspberries, and rum. Such endeavors not only satisfy curiosity but also enhance astronaut training, preparing them for the sensory experiences of space exploration.