I'd like to know what is the lightest possible solar array per unit power with current or near future technology.
The arrays I have been able to find:
- Vanguard Space THINS 400-500 W/kg (2014; thin film)
- SLASR 362 W/kg (2006; concentrator with GaAs cells)
- SCARLETT 45 W/kg (1998; concentrator with GaAs cells; flown on DS-1)
- Orbital/ATK UltraFlex 150 W/kg (since 1995-98; triple junction GaAs; flown on Mars Phoenix and Mars Insight)
Thin film solar cells (for example CIGS) can have efficiencies around 10% with a thickness of 1-3 microns (excluding substrate). A 10 micron laminate with a thin film solar cell would weigh 30-50 g/m^2 depending on composition; this would put the output at 2600-4300 W/kg, which might be a reasonable ballpark near-term goal without major technology advances. With a bit of a stretch, a 3-5 micron laminate with a 1-2 micron cell could be over 10 kW/kg. From that perspective, the numbers for existing arrays are a bit low.
What is the state of the art and most promising research for ultra-lightweight solar arrays? What are the major technical challenges to higher power/mass ratios?