Chemistry World introduces us to a particularly talented NASA veteran, George Aldrich – an expert smeller whose olfactory sensitivity ensures that bad smells don’t disrupt missions in space – where atmosphere is precious:
Aldrich is not a chemist and never attended university – he joined Nasa’s White Sands Test Facility in New Mexico in 1973, straight after graduating from high school. ‘My dad worked out here, and he called me and said they were looking for five temporary hires,’ Aldrich recalls. He immediately quit his job to take one of these provisional posts, before becoming a fireman guard for the site. It was his fire chief, who belonged to Nasa’s first odour panel, that got Aldrich into the smelling business at the tender age of 18. ‘He told me about it, since I was young and healthy, and said it was a great thing to do for the astronauts,’ Aldrich adds.
As astronauts are in a ‘closed loop’ environment where air is recirculated, the delicately-balanced environment could be upset by a smell that is toxic or overwhelming: in space, you can’t just open a window. In the 1970s, the Russians had to abort a space mission shortly after lift-off because of a bad odour inside the space capsule; Nasa doesn’t take any chances.
To prepare for odour testing, Nasa places the material that it intends to launch in a glass desiccator and heats it to around 49°C for 72 hours, then lets it cool. Next, the agency selects five people from its odour panel to smell the samples. First, a nurse inspects their noses and throats to ensure that they don’t have a pre-existing condition that could cause them harm or affect the test, like a raw throat or bloody nose. Then the sniffing begins.
‘We just come in, one at a time, and we are subjected to the gas of that material three times,’ Aldrich says. Each of the panel members then rates the smell on a scale of zero (undetectable) to four (revolting). Any material that scores over 2.5 fails the odour test. ‘We report back to the customer that it is slightly over the threshold for odour, but if it is very important for that object to fly, it might fly anyway. Or, they might try flying something else that might be less toxic.’
Once these odour tests are completed, the nurse returns three hours later to recheck the participants’ noses and throats to determine whether the material caused adverse effects.
All of this volunteer work is separate from Aldrich’s official role, which is to conduct toxicity testing on objects before they go into space.