Another plan, proposed by Bradley C. Edwards, is to beam power from the ground. This plan utilizes 5 200 kW free electron lasers at 0.84 micrometres with adaptive optics on the ground to beam power to the MPD-powered spacecraft, where it is converted to electricity by GaAs photovoltaic panels. The tuning of the laser wavelength of 0.840 micrometres ( per photon) and the PV panel bandgap of to each other produces an estimated conversion efficiency of 59% and a predicted power density of up to . This would be sufficient to power a MPD upper stage, perhaps to lift satellites from LEO to GEO.