(NEXSTAR) – Currently, there are seven individuals aboard the International Space Station, sharing the experience of working, eating, exercising, and living together within the station’s confined, airtight habitat.

So let’s talk about what it might smell like up there.

Astronauts who have spent time on the ISS often comment on its unique odor, often described as unforgettable.

In a 2017 interview with Wired magazine, former NASA astronaut Scott Kelly compared the smell to that of a jail he once visited, describing it as a mix of antiseptic, trash, and body odor. He clarified that while the astronauts themselves don’t typically have strong odors, their workout attire might.

“We use deodorant, we wipe, rinse off, shower. But there’s definitely some body odor involved. Primarily, it’s the exercise clothes worn for weeks without being washed,” Kelly explained.

Years prior, he mentioned to CBS News that various parts of the ISS have different levels of pungency, a sentiment echoed by Samantha Cristoforetti, an Italian astronaut with the European Space Agency. During her 2022 visit to the station, she explained on TikTok that while the ISS has a distinctive smell, certain areas tend to be more odorous.

Among the stinkier parts, Cristoforetti pointed out the spots where trash is stored, solid human waste containers are kept, and near the exhaust of the “brine processor,” which removes water from urine.

NASA astronaut Bob Hines, who lived on the ISS with Cristoforetti in 2022, said his first whiff of the ISS was a mixture of “old luggage” and a “hospital-type smell,” he told Boston’s Museum of Science. The reason for the former, he said, was because of the many cargo bags stored throughout the station, while the latter was due to the crew’s cleaning and sanitation protocols.

Of course, NASA is always looking for ways to mitigate the odors. The space agency relies on air filters to remove not only carbon dioxide, but gases produced by scientific experiments and human bodies. And engineers and chemists with NASA have also researched ways to contain bad odors before they become distractions for crew members.

“We really want astronauts to be able to focus on their job,” Susana Tapia-Harper, who managed the odor lab at NASA’s test facility in New Mexico, told WHYY of their work in 2021. “If you can imagine if you had to do your homework in a nasty bathroom, it would be hard to concentrate. So that’s the kind of situation we want to avoid for our astronauts.”

These mitigation efforts are also likely why some of the same astronauts who spoke of the smells on the ISS — Kelly, Cristoforetti, Hines — say they aren’t all that terrible, despite their initial impressions.

Cristoforetti called the air filters “very good” and claimed she wasn’t able to detect any consistent smells “within a matter of days” after arriving. And Hines said “you don’t even notice it” after a while.

Canadian astronaut Chris Hadfield once went as far as saying that the ISS has a “pretty clean” smell, like one that a person might encounter when walking “onto an airplane” or into a “nice clean hospital building.”

“We work hard to keep it smelling good and healthy. It’s good for our health, and doesn’t let any bacteria grow,” Hadfield continued. “And it’s better if it doesn’t have a smell that you don’t like.”