Thanks to George Aldrich and his team of NASA sniffers, astronauts can breathe a little bit easier. Aldrich is a chemical specialist or "chief sniffer" at the White Sands Test Facility's Molecular Desorption and Analysis Laboratory in New Mexico. His job is to smell items before they can be flown in the space shuttle.
Aldrich explained that smells change in space and that once astronauts are up there, they're stuck with whatever smells are onboard with them. In space, astronauts aren't able to open the window for extra ventilation, Aldrich said. He also said that it is important not to introduce substances that will change the delicate balance of the climate of the International Space Station and the space shuttle.
More than being merely unpleasant, smells in space can indicate a health threat. Even objects that give off no odor can emit dangerous chemicals by a process called off-gassing. If an object's off-gassing has toxic effects, it can be a matter of life and death.
"Smell is brought out by confined spaces and heat," said Aldrich, "yet astronauts have no way of escaping a smell if it becomes pervasive. If that smell comes from dangerous compounds, it's a serious health threat."
It is Aldrich's job to use his sense of smell to ensure the olfactory comfort, as well as the safety, of astronauts on orbit.
When he was just 18 years old, Aldrich began working at White Sand's fire department and was asked to be on the department's Odor Panel. Aldrich explained that one of the requirements to get a job as a sniffer is a lack of any allergies or respiratory problems. "If you have a lot of allergies, your nasal passages are already irritated and cannot be used," he said.
NASA calibrates and certifies its sniffers' noses every four months using a "10-bottle test" in which seven of the bottles have odors and three of them are blanks. The seven scents must be categorized as musky, floral, ethereal, camphoraceous, minty, pungent or putrid.
According to the NASAexplores Web site, Aldrich's team tests nearly all items that astronauts would encounter during their flight — including fabric, toothpaste, circuit boards, makeup and even the ink on their checklists.
First, the items are tested for toxicity. They are placed into individually sealed containers and then into an oven, which is heated to 49 degrees Celsius (120 degrees Fahrenheit) for three days to speed up the off-gassing process. The gases are then extracted and tested to determine whether they are toxic or carcinogenic. If the gases are deemed safe, the items then undergo odor testing.
Aldrich and four other team members smell the items and rank them on a scale of zero to four, ranging from non-detectable (zero), to barely detectable, easily detectable, objectionable and offensive (four). Aldrich refers to level four as "get-me-out-of-here." Because the sense of smell can vary from person to person, sniffers give each object its own ratings, from which an average is obtained. If an item rates more than a 2.4 on the scale, it fails the test and is not allowed on the flight. Some items that have failed are camera film, felt-tipped markers, mascara and certain types of stuffed animals. Aldrich has done 765 of these "smell missions" to date.
NASA could use dogs or "electronic noses" for this testing, but as Aldrich pointed out, the Agency would rather use human sniffers because they serve as a screening test for the also-human astronauts. The human testers can more accurately identify smells that will offend the human crewmembers than an electronic nose could.
As a result of his career, Aldrich has had some uncommon opportunities. He has served as a judge four times at the Odor-Eaters Rotten Sneaker Competition. He has also appeared on television a number of times, including appearances on two game shows.
While others may chuckle at his unusual occupation, Aldrich said he believes in its value.
"I wouldn't be doing it if I didn't think it was important," he said.
This article originally appeared on NASA. Follow @NASA on Twitter.