One of the major disappointments of the Apollo 11 landing in 1969 was the discovery of the complete absence of beer on the Moon. The situation may only temporary, though. A team of University of California San Diego engineering students are working on an experiment to brew the first beer on the lunar surface, and it may fly by the end of this year.

Finding a way to brew a pint on the Moon may seem a bit frivolous to some, but there's a serious purpose behind it. While the UC Sand Diego team admits that it did start out as a bit of a joke, their reasoning is that if the fermentation of yeast, which is at the heart of brewing, can be carried out on the Moon, it will not only be a boon to thirsty astronauts, but also the key to everything from baking lunar bread to creating sophisticated pharmaceuticals.

The UC San Diego experiment, called "Team Original Gravity," is one of the finalists in the Lab2Moon competition – a sub-competition held by India's TeamIndus, which is sending a lander to the Moon as part of the Google Lunar XPRIZE challenge that's scheduled to launch on December 28 of this year.

If you're expecting the students to set up a full-blown robotic brewery on the floor of a lunar mare, you'll be in for a disappointment. The experimental apparatus is only about the size of a soda can and the laws governing unmanned probes mean that special precautions need to be taken to prevent biological contamination of the landing area. This means that the experiment is like one of those home brewing kits where half the work's already been done. Instead of taking hops and barley to the moon for brewing, the unfermented beer or wort will be preprocessed on Earth. This means that starting fermentation means simply bringing wort and yeast together and letting nature take its course.

"Our canister is designed based on actual fermenters," says Srivaths Kaylan, a fourth year nanoengineering major and mechanical lead for the team. "It contains three compartments — the top will be filled with the unfermented beer, and the second will contain the yeast. When the rover lands on the Moon with our experiment, a valve will open between the two compartments, allowing the two to mix. When the yeast has done its job, a second valve opens and the yeast sink to the bottom and separate from the now fermented beer."

Another simplification is that the canister combines the fermentation and carbonation phases into one, so it's a bit like bottle-conditioned beer, where the beer is allowed to continue fermentation in the bottle. According to the team, this simpler design eliminates the need to vent carbon dioxide, so it's more sanitary and avoids the sort of over-pressurization that space engineers frown upon.

Since there won't be anyone on the Moon to taste the finished product, this emphasis on fizz may seem a bit pedantic, but it is necessary because the traditional way of testing yeast fermentation is by measuring density, which relies on gravity. Since the Moon has only a sixth of Earth's gravity, the team has opted for measuring pressure as an alternative.

"Converting the pressure buildup to fermentation progress is straightforward, as long as volume and original gravity — specific gravity before fermentation, hence our name — are known prior to the experiment," says Han Ling, a fifth year bioengineering undergraduate.

The UC San Diego experiment final prototype is scheduled to be evaluated by an international jury at Bangalore, India, in March.

Source: UC San Diego