Production of food in space via photosynthetic crops similar to the ones
we use on Earth requires profligate use of resources that will be in
short supply in early long duration space missions. We demonstrate that
production of bulk calories via chemotrophic single cell organisms is 2
to 3 orders of magnitude less expensive in terms of energy, volume, and
water usage than via photosynthetic crops. In addition we survey the
history and current state of the art in production of food from
non-photosynthetic single cell organisms.