NASA has proposed a series of missions called “Fire and Ice”. Aspects of these missions include a search for ice caps on Mercury and the Solar Probe to explore the Sun’s corona and the solar wind. These missions pose significant challenges for power systems that use photovoltaic power sources. This paper discusses a range of photovoltaic options for this class of missions and presents a simple methodology for selecting the appropriate technology. A range of photovoltaic power systems with band gaps from 1.0 to 3.0 eV is considered. The power output as a function of solar distance is presented and the implications discussed.