The secret to pulling off long-term manned space missions is biomanufacturing – at least, that's the argument presented by scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) who have used synthetic biology to produce sustainable alternatives to fuel and anti-malaria drugs. Their theory rests on the idea that biological production processes and harnessing of materials at the mission destination could dramatically reduce mass (and hence cost) requirements.
Even in the estimations of SpaceX founder Elon Musk, a manned mission to Mars will cost in the order of billions of dollars. Much of that cost will be down to the mass of food and fuel (the Berkeley researchers cite estimates that fuel will be two-thirds of the total ship mass for a return trip to Mars). But if astronauts can generate some portion of their fuel, food, medicines, and tools through synthetic biological processes, the ship mass could be reduced significantly.
For a 916-day manned mission to Mars, for example, the researchers determined that such methods could shrink the mass of fuel manufacturing by 56 percent, the mass of food shipments by 38 percent, and the shipped mass to 3D print a habitat for six people by 85 percent.
The researchers base their figures on estimated crew-generated waste coupled with breakdowns of typical Martian atmospheric and soil composition – which indicate a plentiful supply of carbon dioxide and nitrogen.
Excavated carbon dioxide could be converted to methane for fuel, with the additional 6 kg (12 lb) produced daily by crew members also converted into methane to power jet packs for emergency use. Food stocks, meanwhile, which would be needed in the vicinity of 10,000 kg (22,000 lb) to sustain a six-person crew for the full mission, could be reduced thanks to photosynthetic bacteria that would enable plant-based space farming.
Further mass reductions could come from partially-synthesizing the raw materials needed for 3D printing with nutrients obtained on Mars, and also in using microbes to replenish expired or irradiated pharmaceuticals – with an additional benefit of independence from unmanned re-supply spacecraft.
"The mineral and carbon composition of other celestial bodies is different from the bulk of Earth, but the Earth is diverse with many extreme environments that have some relationship to those that might be found at possible bases on the Moon or Mars," says Adam Arkin, a senior author on the study and director of Berkeley Lab's Physical Biosciences Division.
Their work may be largely speculative, and much of it depends on overcoming still-significant biomanufacturing challenges, but lead author Amor Menzes is upbeat: "We’ve got a long way to go since experimental proof-of-concept work in synthetic biology for space applications is just beginning, but long-duration manned missions are also a ways off," he says. "Abiotic [physical, non-biological] technologies were developed for many, many decades before they were successfully utilized in space, so of course biological technologies have some catching-up to do. However, this catching-up may not be that much, and in some cases, the biological technologies may already be superior to their abiotic counterparts."
And the practicality of synthetic biology, once the technology is fully ironed out, is hard to ignore. Not only will it make long-distance and long-term space travel more feasible, Arkin points out, but "it could also be transformative once explorers arrive at their destination."
A paper describing the research and the Berkeley team's calculations was published in the Journal of the Royal Society Interface.
Source: Berkeley Lab
