In-space manufacturing is expected to become a core part of future space economy by using assets in orbits or beyond Earth orbit for use in space. Tech Briefs interviewed Tempe, Arizona-based space-focused solar energy startup Solestial’s CTO Stanislau Herasimenka about the key technology developments leading to this increased momentum for space-based manufacturing and the role solar power will play in it. Solestial develops radiation-hardened silicon photovoltaics specifically engineered for use in space environments.
According to Herasimenka, the interest in space-based manufacturing for certain industries is being driven by several key technological developments including falling launch costs, increased private investment in space, and advancements in automation and robotics. “That said, in-space manufacturing is still in its early stages of development. Microgravity offers potential advantages for the partial manufacturing of certain pharmaceutical components, a possibility currently under scientific investigation. While not currently viable, inspace manufacturing holds future potential for space solar power applications,” he said.
Here is the full interview with Herasimenka, edited for length and clarity.
Tech Briefs: In-space manufacturing such as orbital servicing and assembly requires sustained energy. How can solar power provide reliable, cost-effective, and abundant energy in space?
Stanislau Herasimenka: Solar power has been the primary source of power for the vast majority of spacecraft for many decades. New advancements in solar energy for space are making it more efficient and accessible than ever before.
Incumbent space solar technology, so-called III-V photovoltaics, have been used in space for decades. While highly efficient, the technology has its limitations. The availability of III-Vs is limited by long lead times due to high demand and slow manufacturing processes. Additionally, III-V component materials are difficult-to-source and expensive.
By comparison, the terrestrial solar industry uses accessible-to-source, affordable silicon and automated manufacturing to deliver its products quickly and at lower cost. While highly affordable, terrestrial silicon degrades rapidly in space due to radiation and other types of degradation, making it unsuitable for space power infrastructure missions.
New advancements in silicon photovoltaics for space are unlocking radiation hardened solar power options with lower costs, higher manufacturing scale, and shorter product lead times. Solestial, for example, upgrades silicon photovoltaics for space using proprietary defect engineering and by making solar cells extremely thin. We leverage the well-established, automated manufacturing processes of the terrestrial silicon industry to create a faster-to-manufacture product that can withstand the rigors of space. Solar energy has become a critical bottleneck for development in space. Solestial is uniquely positioned to solve this problem by providing a more affordable, reliable, and abundant energy option.
Tech Briefs: What is solar photovoltaics and why is it beneficial for space applications?
Herasimenka: Solar photovoltaics (PV) is a technology that converts sunlight directly into electricity using semiconductor materials. This conversion happens at an atomic level: When photons from sunlight strike the solar cells, they excite electrons, creating an electric current.
For space applications, solar PV is incredibly beneficial for several reasons:
Reliable: In space, there is no atmospheric interference, which makes sunlight much more abundant and consistent than on Earth. This makes solar PV an ideal and reliable power source for spacecraft.
Lightweight: Modern solar cells are becoming increasingly efficient and lightweight. This is crucial for space missions where every gram of spacecraft affects launch costs. Deployable solar arrays can be rolled compactly for launch and then unfurled in space to provide large surface areas for energy collection.
Safe: Unlike nuclear power sources, solar PV doesn’t involve radioactive materials, reducing risks associated with launch accidents or end-of-life disposal.
Versatile: Solar PV can power a wide range of space missions, from small CubeSats to large space stations, adapting to varying power requirements.
In essence, solar PV provides reliable and safe energy for virtually all space missions.
Tech Briefs: Solestial is developing silicon-based solar cells designed to self-heal radiation damage. Can you tell us more about how your technology works?
Herasimenka: Using proprietary processes developed through our founders’ academic research, Solestial has created radiation-hardened silicon for space. Radiation-hardened means that our solar cells self-heal radiation damage at normal operating temperatures in space. While certain types of solar cells can anneal radiation damage, it is at high temperatures, higher than normal operating temperatures. Solestial is the only solar technology that self-heals radiation damage at operating temperatures as low as 65 ºC.
An additional benefit of our radiation-hardened solar cell is that it allows us to reimagine cell packaging. Unlike III-V solar cells, we do not need to use heavy cover glass to protect solar cells from radiation and other damage. Instead, we replace cover glass with polymer layers, resulting in an ultrathin solar cell that is flexible, low mass, and able to withstand up to 10 years in a variety of destinations in space.
Tech Briefs: How does Solestial’s technology compare to traditional III-V solar cells in performance and cost?
Herasimenka: Solestial’s radiation-hardened silicon technology for space presents several compelling advantages over traditional III-V solar products. Key differentiators include:
Lead time: Traditional III-V solar cells often require lengthy lead times due to slow, complex manufacturing processes. Solestial’s silicon-based technology leverages established silicon manufacturing infrastructure, significantly reducing lead times and enabling faster deployment of space solar solutions. This speed is crucial for rapidly evolving satellite constellations and demanding mission timelines. Solestial’s lead time is months compared to years for III-Vs.
Manufacturing scale: The production of III-V solar cells is inherently limited by the availability of expensive component materials and the complexity of their fabrication, which restricts manufacturing scale. In contrast, Solestial benefits from the vast, mature, and highly scalable terrestrial silicon industry. This allows for high-volume, automated production, ensuring that Solestial can meet the growing demand for space solar power, particularly for large constellations.
Cost: The cost of III-V solar cells is substantially higher due to expensive raw materials. Solestial’s silicon-based approach dramatically reduces manufacturing costs by utilizing silicon–one of the most abundant materials on Earth–and leveraging highly optimized, lowcost fabrication techniques borrowed from the terrestrial solar industry.
Lightweight and flexible: Our radiation-hardened silicon solar cells do not require heavy cover glass for cell protection. This allows us to package our solar cells using thin polymer layers. Our solar cells and solar power modules are thin, lightweight, and flexible, easily lending themselves to the next generation of roll-out solar arrays. Our solar power modules have a 5-centimeter bend radius and can be easily spooled for launch and unfurled for deployment. Thinner cells and modules reduce weight, which not only decreases launch expenses for our customers, but also frees up valuable payload capacity for other instruments or mission objectives.
Tech Briefs: What’s Solestial’s roadmap for deploying and scaling the technology? What are the biggest challenges in scaling manufacturing of ultrathin solar blankets for space and how are you planning to overcome them?
Herasimenka: In May, we announced the successful close of our $17-million Series A funding round. This significant capital infusion is crucial for Solestial as it enables us to continue scaling our space solar manufacturing capabilities, an endeavor that is inherently capital-intensive due to the specialized equipment and processes required. This investment underscores the confidence our investors have in our breakthrough approach to space solar power.
Concurrently with this funding announcement, we were thrilled to welcome Margo de Naray as CEO. Margo brings a wealth of experience to Solestial, having previously led the successful scaleup of the electric propulsion business at Astra. Her two decades of extensive commercial and operations management experience, particularly in dynamic growth and high-tech environments, have been invaluable as we navigate the complexities of rapidly expanding our manufacturing footprint and market presence.
I transitioned to the vital role of Chief Technology Officer where I can drive the advancement of our product roadmap and rapidly scaling our core operations technology. This strategic shift has already accelerated our manufacturing ramp.
The Series A funding is a critical step, but we recognize that continuous access to capital will be essential. We are actively managing our financial resources to ensure efficient allocation toward R&D, manufacturing expansion, and talent acquisition.
Rapidly scaling operations is our top priority as we currently have more customer demand than we can fulfill. We are implementing advanced automation, optimizing our supply chain, and developing robust quality control systems to enable high-volume, cost-effective production of our ultrathin solar power modules.
Rigorous testing is paramount for space-grade hardware. We are conducting comprehensive in-house testing, simulating the harsh conditions of space to ensure the reliability and performance of our solar cells and modules. Furthermore, we are actively collaborating with our aerospace partners on joint testing and validation programs, integrating our technology into their missions to gather real-world data and continued flight heritage. This collaborative approach ensures that our technology meets the highest standards of reliability and performance required for critical space applications.
By strategically addressing these areas, Solestial is well-positioned to overcome the challenges of scaling to deliver reliable, high-performance power solutions for the rapidly expanding space economy.
Tech Briefs: As space missions shift toward long-duration operations and in-space manufacturing, how do you envision Solestial’s solar technology powering the next generation of orbital infrastructure or deep-space missions?
Herasimenka: Solestial’s solar technology is uniquely suited for the next generation of orbital infrastructure and deepspace missions due to its inherent radiation hardness, lightweight nature, and lower cost than III-Vs. For long-duration orbital operations, our silicon solar cells are engineered to withstand up to 10 years in a variety of destinations in space. This longevity is critical for maintaining permanent outposts on the Moon or large-scale satellite constellations.
For in-space manufacturing, the low mass and volume of our solar power modules significantly reduce launch costs, making it more economical to deploy the extensive power arrays needed for energy-intensive manufacturing processes. Furthermore, our technology’s ability to be manufactured at scale on Earth using automated processes translates to potential for in-space assembly and even potential for in-situ resource utilization for future deep-space missions.
This article was written by Chitra Sethi, Editorial Director, SAE Media Group. For more information, visit here .
