Get your toilet humor and poop puns ready – it’s time for another edition of “What do astronauts do with all that doo-doo?” NASA recently asked researchers to come up with a way to use all of the human waste expected to pile up when it builds a moon base. The best answer was to use it to fuel spacecrafts on their trips back to Earth.

Up until now, astronauts saved their waste and burned it off on re-entry. Concerned about waste weight, wasted space and long-term waste storage on the moon, NASA asked Pratap Pullammanappallil, a University of Florida associate professor of agricultural and biological engineering, for an alternative.

Using chemically produced human waste supplied by NASA, Pullammanappallil determined that the waste of an average crew could produce 290 liters of methane per day using a process that takes about a week. He used an anaerobic digester that killed pathogens and produced a biogas mixture of methane and carbon dioxide that would fuel returning spacecrafts. According to his report published in the journal Advances in Space Research, the digester also produces non-potable water which can be broken down into hydrogen and oxygen, with the oxygen being used for breathing.

What took NASA so long to come up with this idea? The Bath Bus Company in the UK already has a 40-seat Bio-Bus powered by human waste. Let’s hope the windows don’t open and it has a sign on the rear telling drivers to stay far back. What will they do on the moon where those smells will be trapped in the habitat? Koehler just announced a new toilet seat with a fan that pulls offensive air in and passes it through a filter and over a scented pad. No more “I wouldn’t go into that waste disposal pod if I were you.” In fact, why worry about smell at all? A French inventor has developed pills that make flatulence smell like chocolate or roses. Makes every day on the moon smell like Valentine’s Day.

There are solutions to every problem, NASA. You just need to ask the right people.