Growing food on Mars for long-term space exploration has many benefits including reduced fuel and cost requirements for lift-off, improved nutrition and psychological benefits for astronauts, air purification, and oxygen and water regeneration. However, complications are caused by the thin atmosphere on Mars, which would force production underground or into a heavily armored shelter. Providing the massive number of photons necessary to grow food is expensive and careful consideration must be made regarding the most promising technologies. The two most promising options are a combination of either concentrating mirrors coupled to solar-fiber-optics (SFO), or photovoltaics (PV) coupled to light-emitting diodes (LEDs). Here we discuss the efficiency, equivalent system mass, and photobiological potential of both systems. Recent advances in PV and LEDs mean that they have caught up to SFO technology and now appear to be the superior technology
