The proposed study would investigate a system architecture with the potential to provide solar-powered transportation to the outer planets and solar power in orbit at the destination. This architecture consists of two key features:
- Very large, deployable solar arrays to provide power at the outer planets (roughly a few thousand square meters per wing with areal densities of order ~100 g/m2).
- Direct-drive electric propulsion systems to take advantage of the high-power provided by very large solar arrays to deliver them to their destinations. Ideally, such electric propulsion systems require the development of high-voltage solar arrays with output voltages of order 1 kV and should be throttleable over a large input power range (≥100:1).
We will take build this architectural approach with broad community, identify and address feasibility issues, and define a roadmap of useful technology demonstration and operational missions that lead to the desired end state—an alternative approach for solar system exploration that requires no use of nuclear power sources. The conceptual, non-nuclear exploration architecture would include: solar-powered orbiters, battery-powered landers and rovers, and solar-powered sample return vehicles.
There are four emerging technologies that make this the right time to investigate the potential and limitations of a non-nuclear solar system exploration architecture. The proposed study will investigate how these technologies can be combined to enable this new exploration capability:
- Development of very lightweight, large-scale photovoltaic arrays with a per wing area of order 3000 m2 and areal densities in the range 100 to 200 g/m2. These performance values are consistent with the objectives of the current space solar power work at Caltech.
- Development of solar cells that work efficiently under Low Intensity Low Temperature (LILT) conditions at solar intensities corresponding to solar ranges of 20 to 30 au, or the development of concentrator solar arrays with relatively low concentration-ratios (~10:1).
- Development of solar arrays that have output voltages of 1 to 2 kV that can operate successfully in the plasma environment created by electric propulsion systems.
- Development of direct-drive, electric propulsion systems with a large input power throttling range coupled with the high-voltage solar arrays.