Description: CropGlass is adhered to the top of CIC coverglass in the crops and overlapping a small area of the cell. Light enters through the top of CropGlass and is reflected back upward. Total internal reflection keeps the light inside CropGlass and the majority of the light is directed laterally through CropGlass and then downward onto the overlapped cell area. CropGlass is a very low risk technology, as it is made from entirely flight heritage materials, it is low profile and it has no moving parts. Additionally, CropGlass leverages mature nano- and micro-fabrication techniques which will result in a low cost for high volumes. CropGlass offers the ability to increase power or decrease cost without influencing other solar array design parameters. Very large solar arrays will benefit most because of the huge power levels and cost of these programs. Because CropGlass can be added to a complete array, this innovation will also be beneficial to completed solar array programs that experienced less than anticipated power or increases in needed power late in the manufacture of the solar arrays. Competing approaches include reflective concentrators such as panel edge reflectors. What makes crop glass unique is that it is flat, requires no deployment of optics and does not require a custom solar panel or blanket design. No existing concentration technology offers such a low cost, low risk and flight heritage-based path to higher power and lower cost. CropGlass concentrates light at less than 3x. Past industry attempts at concentration above 10x have shown many engineering challenges at these high concentration levels. These challenges include heat rejection, outgassing of concentrator material and power loss in off-pointing. Conversely the industry has heritage of successful concentration at lower levels.

Benefits: We expect direct commercialization after Phase II for this technology, by leveraging the flight-heritage of CropGlass materials and the experience of our commercial partner. We expect applications post-Phase II should be in the form of purchase contracts with our subcontractor and commercialization partner, ATK. This cost-saving technology will be highly relevant to NASA and commercial aerospace firms alike. Additional possible post applications will include mission specific studies of this technology, including different orbits or special requirements. Integrating this technology into the manufacturing workflow of the major solar cell suppliers (Spectrolab, Emcore) represents another post application opportunity. We expect that after a successful Phase II effort that the community will see this technology as low risk. The cost savings will particularly useful to missions that require very high power levels. NASA programs involving large solar arrays, such as the solar electric propulsion (SEP) demo, would be particularly interested in CropGlass.

Department of Defense, foreign government programs and the commercial sector all have an interest in greater power and lower cost for solar arrays. With the vast majority of space missions powered by solar arrays, and given the low risk nature of the design, CropGlass has large potential across broad markets.