Food production in space from CO2 using microbial electrosynthesis

•Microbial electrosynthesis of acetic acid could lower the cost of space missions.•In space, it is 1.38 times lower mass than the current standard (prepackaged food)•It is cost-competitive with microalgae-based life support systems.•It is likely more energy efficient than alternatives (∼19.8 % electricity-to-calories)•It is estimated to consume only 3.45 kW of electricity to feed five astronauts. The current food method in space is launching prepackaged food which is costly and unsustainable. Alternatives include growing crops and microalgae single cell protein (SCP) using artificial light photosynthesis, which are energy inefficient. Prepackaged food and microalgae food were compared to microbial electrosynthesis of acetic acid (MES-AA). Since the dominant cost of a space mission is the cost of launching mass, components of a system were converted to an equivalent mass, including power, heat rejection, and volume. Three-year roundtrip crewed missions were evaluated for the International Space Station, the Moon, and Mars. The average Equivalent System Mass (ESM) of MES-AA is 1.38x and 2.84x lower than prepackaged food and microalgae SCP, respectively. The expected electricity-to-calorie conversion efficiency of MES-AA is 19.8 %, consuming 3.45 kW to fully feed five astronauts; diets would realistically include multiple foods. MES-AA has a higher energy efficiency than any currently investigated resilient food in space. MES-AA can provide diet diversity at a lower cost than customarily storing prepackaged food or growing crops in space. Producing food while contributing to closed loop life support in space can contribute to reducing global catastrophic risk and is relevant in off-grid communities, like in rural Alaska.