The global food system is increasingly complex. When we can’t see the wood for the trees, it pays to step back. Way back. In the spirit of citizen space travel in 2021, this pre- sentation reframes the problem of how to optimise a food system by considering how we might do so on Mars. If we had a blank piece of paper, what would we do? Producing food on Mars would require absolute efficiency. Every molecule would count. Food must be safe to eat and production must replenish the environment. This paper outlines four key aspects to consider, puts people at the centre and references great case studies here on earth that progress our knowledge and capabilities: