2022 Focus Event Topics

Mission designers have long chosen high-durability, high-efficiency multijunction photovoltaics for space missions which typically require the highest possible performance in turning solar energy into direct-current energy. Unfortunately, the production of these devices requires expensive, high-quality crystalline substrates, precision epitaxial deposition systems, and meticulous device and module fabrication processes that drive costs to more than 100 times that of terrestrial silicon photovoltaics. Many space missions require high beginning-of-life conversion efficiency (>30%, 1 sun air mass zero at 28C) and durability in the space environment (such as resistance to darkening to ultraviolet light, stability through thermal cycles, and high energy radiation resistance) that terrestrial silicon solar cells cannot achieve. Increased efficiency also reduces the mass, deployed area, and stowed volume at the solar array level.

• Both NASA and commercial satellite providers would greatly benefit from technology that enables manufacturing low-cost, high-efficiency photovoltaics for space applications at a high throughput scale for <$25 per watt. Potential solutions include—but are not limited to—the growth of substrates, including reuse and alternative materials, low-cost deposition methods that maintain high-efficiency performance, and cell processing (metallization, etching, packaging). U.S. Department of Energy (DOE) National Renewable Energy Laboratory (NREL) techno-economic studies have indicated that these cost reductions for III-V photovoltaics are possible at large scale.

On Earth, logistics innovations have allowed industry to ship more and more and waste less and less. However, the packaging needed to deliver a given product can sometimes still outweigh and outsize the product itself, leaving a large percentage of packaging waste at the delivery destination or point of use. The packaging problem is magnified when many small items need to be packaged and organized into larger packages and when the deliveries must cover long distances under harsh environmental conditions. Logistics deliveries in space exemplify all these challenges. The significant packaging required can lead to substantial packaging waste.

NASA seeks point-of-use recycling solutions for common waste streams produced in space. This includes the packaging waste stream, produced by logistics supply missions, but could also entail recycling other common waste streams, such as food waste, human waste, or paper, plastic, or cloth waste. Astronauts may recycle waste streams individually or combine them into mixed waste streams for more efficient recycling.

Point-of-use recycling systems in space must be efficient and fit into a small footprint. Astronaut crews cannot spend valuable time separating or preparing the waste for recycling. Finally, the recycled products must be useful, reducing the need for future crew supplies. Recycled materials may serve as feedstock for 3D printing or as resources for other manufacturing processes, or crews may convert recycled materials into other items for end-use. Examples of this might include resealable plastic bags and containers, paper towels, radiation shielding, tissues or other paper or plastic products produced from recycled packing materials or other common waste streams. In this way, all of the materials delivered—including the packaging—can be recycled and used, wasting nothing. Point-of-use recycling innovations could also offer efficient ways to make direct use of unwanted packaging waste here on Earth, offering alternatives to placing it in a recycling bin that may, or may not, eventually reach a recycling center.