NASA's Chief Odor Expert Works to Prevent 'Stinky' Issues in Space

Before anything—every screw, zip tie, or even a container of Tang—goes to space, it undergoes rigorous checks. After all, it only makes sense: space isn’t a place for unexpected issues.

Testing every item—ensuring it performs as expected in extreme conditions—is the responsibility of a dedicated team at NASA’s White Sands Test Facility in New Mexico. Among them, the Materials Flight Acceptance team meticulously assesses the space-readiness of materials, guaranteeing that nothing will catch fire, release toxic gases, react oddly in the vacuum of space, or cause adverse reactions with other materials onboard. The main priority: ensuring astronaut safety.

One of the unique testing areas that has made the Materials team a bit of a celebrity within NASA is the odor panel.

It turns out that what astronauts smell in space is actually a critical part of the mission as well.

"If you can’t stand the smell of fish on Earth, you can simply open a window and let it air out," says Susana Harper, the manager of the Materials Flight Acceptance standards testing at White Sands. "But in space, we don’t have that luxury."

Why Smell Is So Important in Space

While the occasional bad smell like halibut or a farting co-pilot is unpleasant, NASA’s concerns go beyond just simple odors. (After all, certain smells in the confined space of the International Space Station or Orion are inevitable.) "Our goal is to avoid creating an environment that distracts or bothers the astronauts so they can remain fully focused on their mission," Harper explains.

In addition to ensuring astronauts' comfort—which is undeniably important—NASA also keeps unwanted smells out of spacecraft for a practical reason: too many unfamiliar scents in a confined space could potentially mask odors astronauts need to identify, such as an ammonia leak or the smell of something burning.

There can't be too many odors onboard, or astronauts might miss detecting crucial ones.

"Our primary method of detection is the human sense of smell. While we’ve collaborated with companies and use certain onboard detectors," says Harper, "we ultimately trust the human nose as our most sensitive tool for identifying hazardous odors."

NASA's Nose Knows Best

NASA's Materials group operates an odor panel that evaluates what can be sent into space and what simply smells too unpleasant. Five volunteers evaluate every smell found in the astronaut's living area. The odor is first captured in an air chamber, and then the air is injected into masks worn by each panel member using a syringe. They rate the smells on a scale of 0 (least offensive) to 4 ("get this out of here"). Anything that exceeds a rating of 2.5 fails the test. Another team also tests for toxicity before items are cleared.

The panel's most experienced member is George Aldrich, a 64-year-old chemical specialist who has spent nearly 46 years smelling things for NASA. Having participated in over 900 smell tests, Aldrich is the leader in sniffing, earning him quirky titles (such as "nasalnaut"), media attention (including a memorable moment where he sniffed out drugs like a police dog), and the admiration of astronauts. He even received the prestigious Silver Snoopy Award for his contributions.

Although Aldrich has been performing this role since he was a teenager, it's no cushy position—he must requalify for the panel every four months.

To do so, Aldrich and other volunteers are put through the 10-bottle test, where they must identify seven specific smells and identify the three bottles with no scent. "As we age, eyesight is not always the first thing to go," Aldrich jokes. "The day I can’t pass the 10-bottle test is the day I retire from the odor panel."

The seven smells tested are commonly referred to as "primary" odors.

"You want me to list them for you?" Aldrich responds. "Musky, minty, floral, etherous, camphoraceous, pungent, and putrid. I still have it."

It’s worth noting that Aldrich doesn’t have an especially large nose. "Size," he claims, "doesn’t matter." He rarely suffers from allergies, which he believes helps keep his sense of smell sharp. Aldrich continuously challenges his nose, often following scents down hallways to identify them and their source. "I always keep my nose tuned to odors," he says.

"From my viewpoint," Harper remarks, "I also believe he has honed his sense of smell much like a weightlifter enhances their strength or a wine taster refines their palate. He smells countless materials, paying close attention to the nuances of those smells. It's as though he’s been training his nose like a muscle, which has grown more sensitive over time."

Aldrich was once part of the NASA fire department at White Sands when his supervisor introduced him to the odor panel. "I had no idea," he reflects. "I thought I was just doing something beneficial for the astronauts."

Since then, the Materials group has kept him on his toes, providing him and the other panel members with a variety of materials to evaluate, including some truly unpleasant ones. He vividly remembers the particularly foul smell from undoing a Velcro strap as one of the worst offenders.

But Aldrich never complains. For nearly fifty years, he's been proud to put his nose to work in the service of science, no matter the smell.