The other end of eating in space
What goes in must come out – and scientists are getting creative with waste-disposal methods
Of course, food consumption is just the start of a complex set of digestive processes that end – quite literally – at the other end. With no gravity, going to the toilet in space is a tricky procedure. On Glenn’s first flight there were no provisions, and after a launchpad delay, he ended up urinating in his suit. Apollo astronauts didn’t fare much better, having to use a combination of absorbent pads, sheaths and bags – not always successfully.
A document by NASA entitled Biomedical Results of Apollo states ‘the principal problem with both the urine and faecal collection systems was the fact that these required more manipulation than crewmen were used to in the Earth environment and were, as a consequence, found to be objectionable’. Apollo 7 astronaut Walter Cunningham estimated the time required to correctly accomplish the process was around 45 minutes.
Fast forward to today and there are two toilets on the ISS, in both the Russian and US sections, and since 2008 urine – and other waste liquids from showers and condensation – have been recycled into drinkable water.
NASA is planning to return to the Moon by 2024 with the Artemis program, so in June 2020 it launched the Lunar Loo Challenge, offering a prize of $35,000 (£25,000) to anyone who could design the ultimate loo. “The key driver for this toilet compared to other very capable current toilets like the Universal Waste Management System (UWMS) is mass and volume,” says competition organiser Michael Interbartolo. “Our toilet has to not only work in orbit around the Moon, but also on the surface of the Moon, and to get down to the surface takes propellant. There is a significant gear ratio of propellant to mass for items going down to the Moon and back up again, of around 10:1, so our toilet has a very low mass target of 15 kilograms, which is less than the standard twopiece toilet you have at home.” Not only that, but it also has to work for both male and female astronauts and fit in a very small space, like on the Orion Capsule.
The crowdsourcing effort attracted over 2,000 submissions, and NASA awarded prizes to the top five participants. The first prize went to THRONE (Translunar Hypercritical Repository 1). The team presented a novel idea for a bladeless fan to entrain waste, as well as a method for bagging the waste which would minimise crew interaction with waste bags.
But how important is it to get this right? “Toilets are very important for crew wellbeing.
Apollo had a very limited waste-management capability that the astronauts didn’t like and had issues with. While going back to the Moon in 2024 is about starting the scouting for a permanent human presence, we wanted to ensure when that first woman and next man land at the south pole, going to the bathroom is not something they dread,” says Interbartolo.