While the space station orbits high in the heavens, it’s George Aldrich’s job to make sure it doesn’t stink to the high heavens.

Aldrich, whose official title is chemical specialist, works at NASA’s White Sands Test Facility in New Mexico. He uses his nose to protect astronauts from noxious odors that could compromise a mission. He’s NASA’s esteemed head "nasalnaut," and his near four-decade career has involved smelling objects from technical manuals to astronauts’ personal effects.

Why does NASA need the best nose in the business?

On Earth, it’s easy enough to air out a bad smell by opening a window, but when an odor enters the International Space Station, it’s stuck there. It’s critical that all items taken aboard the ISS are stench-free.

Since astronauts are allowed to bring personal or sentimental items aboard, even the most unexpected objects must be smell-checked prior to leaving Earth. In a video provided by Science Channel, Aldrich relates one specific occasion when an astronaut wanted to build a ship in a bottle in space. Everything in the ship-building process had to be sniffed – right down to the glue.

Aside from the olfactory comfort of astronauts, Aldrich and his team at the White Sand’s Molecular Desorption and Analysis Laboratory are responsible for making sure that objects are not harmful or even carcinogenic to astronauts. When the ISS heats up, a process called off-gassing occurs. Objects that would be safe on Earth could give off foul odors or become dangerous when exposed to high temperatures in the ISS’s unique environment.

Of course, humans aren’t the only testers or the first to be exposed to potentially dangerous objects. Before Aldrich sticks his nose into a substance, it has been examined for toxicity and carcinogens by machines including chromatographs and mass spectrometers. Even though machines can detect unsafe substances, computers cannot tell exactly how things smell to humans. While something could be technically fine, it could be malodorous to an astronaut.

After an object is deemed safe to sniff, a chemist creates an extraction, which is then injected into and smelled through a mask.

Aldrich’s nostrils are not alone in the nasal lab. He is the head of a hard-sniffing team of smell testers. Together they smell each object and rate it on a scale of 1 to 4. According to NASA, 1 cannot be detected, and 4 is deemed not bearable. After the scientists conclude their tests, the scores are averaged. NASA says, "If an item rates more than a 2.4 on the scale, it fails the test and is not allowed on the flight."

How Aldrich become NASA’s go-to nose guy

Aldrich, a former firefighter, began his career with the space agency nearly 40 years ago when he signed up to be a volunteer sniffer at the age of 18. According to Wired, “He took his first calibration test and scored a perfect 10 out of 10. He's now taken the test 90 times, and he always gets 10 out of 10." What sets Aldrich’s nose apart from the rest of us is his ability to use his 400 nasal receptors to the fullest each day. It’s not a task for the fainthearted or the tender nosed.

Aldrich doesn't just keep astronauts safe. He even sniffs things never destined for microgravity. For example, he’s helped judge Odor-Eater’s Rotten Sneaker Contest on multiple occasions.

Whether he's smelling tennis shoes or spacesuits, one thing is for sure: George Aldrich has the right sniff.