 However, News Ledge notes that this short transfer time would require a second array of lasers already existing on Mars to slow vehicles down for Mars orbital insertion.DEEP-IN would use an array of small lasers to focus a stream of photons onto reflectors on spacecraft, eliminating the need for spacecraft to carry propellant and therefore significantly lowering their mass.Photon momentum would be translated to the spacecraft, and reflectors enable a theoretical twofold increase in momentum transfer compared to a blackbody surface.