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| Fig. 1: ROSA undergoing in-flight testing on the ISS [1] (Courtesy of NASA) |
Solar power emerges in space applications as the predominant form of energy generation for near-sun environments. Current payload storage limits govern the size and weight able to be brought to space, requiring advanced methods of volume optimization. In addition, as small form-factor satellites such as CubeSats become more commonplace, methods for power generation for such satellites must be optimized to occupy as little volume as possible. Origami deployable structures, which draw inspiration from the ancient Japanese art of paper folding, are one such solution for creating lightweight and compact structures for use in space.
Traditional solar panels necessitate the usage of complex structures to support their rigid designs, increasing weight and bulk required for operation. In space missions today, with launch costs ranging from $10,000 to $30,000 per kilogram, resulting in significant motivation for weight reduction. Origami solar arrays are designed around flexible blankets, with architectures promising increased packing efficiency at a lower cost compared to rigid panel solar arrays. [1] One such system is the Roll-Out Solar Array, also known as ROSA, which is an Origami-style solar array that underwent flight testing on the International Space Station in 2017. Compared to traditional designs, specifically for a 15 kW panel, ROSA would reduce the stowed volume by 75% and the stowed mass by 33% compared to conventional rigid solar arrays. [2] Such efficiency gains directly translate to cost savings and increased payload capacity, making ROSA, as well as other origami-style arrays, a compelling choice for next-generation space missions.
Origami solar arrays rely on intricate folding techniques derived from origami principles, enabling compact stowage and reliable deployment in space. Designs like the Miura folda tessellation-based structure allow for rapid and uniform deployment. The folding mechanism not only reduces the risk of mechanical failure but also ensures that the array occupies minimal space during launch, crucial for missions involving CubeSats or other small-scale platforms. [3] These folding patterns allow for much higher volume efficiency compared to traditional designs, which is an equally important metric as mass efficiency for large spacecraft applications, and are a defining feature of origami solar arrays.
In addition, flexible thin-film photovoltaic materials are often employed in these designs, further reducing mass and increasing resilience to the harsh conditions of space. These materials can conform to the folded structure without compromising energy generation efficiency, achieving energy densities comparable to traditional rigid panels. [4]
Origami solar arrays are designed to withstand extreme thermal fluctuations, radiation, and mechanical stresses encountered in space. By leveraging advanced materials such as Kapton and reinforced polymers, these arrays maintain structural integrity while achieving high energy conversion efficiency, even while under relatively high levels of tension. [4] ROSA, for instance, has demonstrated stable operation in orbit, validating its suitability for long-term use in various space environments.
Moreover, the modular nature of origami designs allows for much increased scalability compared to traditional designs. Missions requiring higher power outputs can deploy multiple arrays, seamlessly integrating them into a compact payload. This flexibility positions origami solar arrays as a critical technology for diverse applications, from low-Earth orbit CubeSats to interplanetary exploration missions.
To contextualize the impact of origami solar arrays, consider the following calculations:
Take an example rigid solar array for a 15 kW satellite, which requires on average approximately 2 cubic meters of stowed volume and weighs about 300 kilograms. [5] At an average launch cost of $20,000 per kilogram, the cost associated with this weight is approximately $6 million.
In comparison, a ROSA array with similar power output requires only 0.5 cubic meters of stowed volume and weighs 200 kilograms. The corresponding launch cost is reduced to $4 million, saving $2 million per deployment while freeing valuable payload capacity.
These savings are even more pronounced for larger arrays or missions requiring multiple launches, highlighting the economic and operational advantages origami-style arrays have to offer. Future developments in materials science, such as ultra-thin and high-efficiency photovoltaic films, could further enhance the performance of origami solar arrays. Integration with autonomous deployment systems and adaptive folding techniques could expand their usability across a broader range of mission profiles. [4]
Origami solar arrays represent a paradigm shift in space-based energy generation, merging the elegance of ancient design principles with cutting-edge technology. By addressing critical challenges in weight, volume, and cost, these arrays pave the way for more efficient and versatile space missions. As research and development continue, the potential for origami-inspired solar technology to transform the landscape of space exploration and beyond is immense.
© Garrett Brown. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] M. K. Chamberlain et al., "On-Orbit Flight Testing of the Roll-Out Solar Array," Acta Astronaut. 179, 407 (2021).
[2] J. Banik et al., "On-Orbit Validation of the Roll-Out Solar Array," IEEE 8396390, 2018 IEEE Aerospace Conference, 3 Mar 18.
[3] Y. Nishiyama, "Miura Folding: Applying Origami to Space Exploration," Int. J. Pure Appl. Math. 79, 269 (2012).
[4] M. S. Lake, W. H. Francis, and K. Craven, "Robust, Highly Scalable Solar Array System," AIAA 2016-1951, 3rd AIAA Spacecraft Structures Conference, 4 Jan 2016.
[5] J. Banik and P. Hausgen, "Roll-Out Solar Arrays (ROSA): Next Generation Flexible Solar Array Technology For DOD Spacecraft," AIAA 2017-5307, AIAA Space and Astronautics Forum and Exposition, 12 Sep 17.