Physical Sciences Inc. (PSI) proposes to develop a plant lighting system which collects, transmits and distributes photosynthetically active radiation (PAR) for biomass production in planetary and transit missions. In this system, solar light or electric lamp light is collected by reflector optics and focused at the end of an optical fiber cable. The light is filtered by a selective wavelength filter to reject the non-PAR spectra to minimize heat generation within the plant growth chamber. The PAR spectra are transmitted to the plant growth chamber where the light is uniformly distributed over the plant growth area at optimum intensities. Key features of the proposed system are: (1) the PAR can be transmitted via a flexible optical fiber cable to plants away from the light source; (2) only the PAR will be transmitted to the plant, minimizing the thermal loading in the plant growth chamber, while the non-PAR spectra can be converted to electricity by means of low band-gap PV cells; (3) the low profile light diffuser makes more volume available for plant growth; and (4) the electric light source can be chosen for the best system efficiency and can be placed at the location best suited for thermal control.