[adastra22]

You would likely use this “food” to feed more traditional agriculture for human consumption. A better way of positioning it is processing the content of abiotic asteroids into a biological system capable of providing nourishment to astronauts and space colonists.

[roughly]

The article says the cost of feeding one astronaut for one year is around 5,000-160,000 tons of ore per year. My understanding is the rule of thumb is about an order of magnitude nutritional drop off each step - that is, to produce 100cal of meat requires 1000cal of plant food. Bumping those yield estimates, especially the pessimistic end, up by another factor of 10 is just a phenomenal amount of material to process for one person for one year.

[Teever]

That's just the mass you need to extract the resources that make up the food that one person consumes in a year. Assuming you don't just space the human waste and instead reuse it you'll be accumulating material that can make up the biomass that will comprise a large and intricate food web that will eventually make up the biomes of large O'Neill cylinder stations.

[pavel_lishin]

I didn't read the paper in depth, just skimmed it, but it seems like their assumption is that the astronauts will be eating some sort of microbe slurry; so I think that the cost includes only that, not using microbes to feed higher-order life or growing plants.

[roughly]

Agree, but the post I was responding to was suggesting it be used as an agricultural feedstock to feed things the astronauts eat - that’s where my order-of-magnitude calculation came from.

[adastra22]

Biomass is recycled. You would only need the replacement rate for losses, which would be nonzero not negligible, but much smaller.