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Over the last decade, decreased costs of launch have unlocked new markets in space. The two largest are satellite communications and Earth observation in low Earth orbit (LEO). As these costs continue to fall with the advent of SpaceX’s Starship, Blue Origin’s New Glenn, Rocket Lab’s Neutron, Stoke Space’s Nova and others, the industry is taking advantage by pursuing newer and more capital intensive businesses beyond Earth’s atmosphere.
Yet launch is only one of many steps in establishing a robust space economy, and falling launch costs have exposed new bottlenecks in the satellite supply chain–and thus new markets for satellite infrastructure. Key components of the satellite supply chain include satellite bus vehicles, power systems (solar panels), electrical and wiring systems (such as wire harnesses), propulsion systems (chemical or electric thrusters), guidance systems (sun trackers), ground support systems (mission control software and ground stations) and more.
Investors are betting on the value of alleviating these bottlenecks, and startups are rushing to own their part of the stack. Closing the gap in satellite bus lead times, Apex Space and K2 Space raised $150 million and $110 million growth rounds, respectively, in just the last few months, to build modular satellite buses. Ursa Major delivers propulsion systems more rapidly by leveraging commercially available rocket engines. Senra Systems is aiming to cut lead times and failure rates for wire harnesses through automation software. However, other bottlenecks persist, and the United States will need to leverage international diplomacy and domestic industry if it wants to stave off a power system shortage before it becomes a crisis.
One of the largest pain points in the supply chain today is access to power in the form of solar cells. An imperative for nearly every satellite, solar cells capture the energy from the sun that generates the electricity needed for satellite missions and maneuvers.
Since the 20th century, these cells have been made of gallium arsenide (GaAs), a material well-suited to handle the harsh environment of space. The space industry has long championed GaAs solar panels, notably different from terrestrial silicon solar panels, because they can withstand radiation in space caused by phenomena like galactic cosmic rays and solar energetic particles.
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But GaAs does not exist in commercially available quantities as silicon does. Today, suppliers produce about 2 MW of GaAs cells a year — enough to power 400 homes or, more pointedly, just a small fraction of the space industry’s current annual demand. This shortage will only grow as the satellite industry is projected to grow by seven times by 2035.
Worse still, 98% of the world’s supply of raw gallium is produced by China. In December 2024, China banned the export of gallium to the U.S. as part of a larger critical minerals ban. Today, the industry faces a shortage in GaAs cells which may well turn into a crisis.
The crisis of accessing gallium lends a window into a much larger story about the geopolitics of critical minerals. That China controls the supply of minerals like gallium is no accident. For over a decade, the Chinese government has offered generous subsidies to catalyze its own mining and processing industries for commonly used minerals like lithium, steel and aluminum, as well as rare Earth elements.
China floods the market with cheap supply and controls the world’s access when competitors are forced to shutter their businesses. This strategy has come into focus for minerals like lithium and aluminum, but gallium is often overlooked despite the criticality of hyper efficient GaAs chips for a range of national security systems, including missile defense, radar, electronic warfare and communications equipment.
China’s dominance in mining gallium arose from its focus on becoming the world’s leading supplier of aluminum, according to a report from the Center for Strategic and International Studies (CSIS). The primary ore used for aluminum also produces gallium, and the Chinese government requires that domestic aluminum refineries be capable of extracting gallium. Further, once a mineral is mined in one region, processing that mineral into a compound, like GaAs, becomes far cheaper.
China issued its 2024 critical minerals export controls, which included gallium, in response to the U.S.’s latest curbs on the most advanced GPUs for training Large Language Models. That gallium was leveraged in response to curbing access to the critical component of the global AI race validates that both countries understand its importance.
Alleviating the crisis of the critical minerals supply will require a range of creative solutions, including relearning the skills and adopting new technologies to bring these industries back to the U.S. or allied countries. Fortunately, for solar cells in space, a much faster and less capital intensive solution exists. A wave of startups is capitalizing on advances in silicon cells to find an alternative to GaAs altogether. Moving to this alternative is both a commercial and national security imperative.
Until recently, the space industry long dismissed silicon as a viable solar cell composition, because of its inability to sufficiently withstand radiation in space. As it often has, SpaceX challenged this conventional wisdom out of necessity — to launch Starlinks in the thousands, the company would need a more abundant solar cell supply than what GaAs offered. Leveraging falling launch costs that SpaceX itself enabled, the company used silicon cells but made its solar panels far larger than otherwise necessary, with space for far more cells, to make up for the efficiency losses of using silicon rather than GaAs. Despite the added weight, the cost of silicon is justified based on its ability to be mass manufactured for proliferated LEO constellations.
Now, as other companies launch proliferated LEO constellations, they cannot afford the lack of availability, schedule constraints and cost associated with GaAs cells. Fortunately, startups such as mPower and Solestial have innovated to fill this rapidly expanding gap with radiation resistant, high volume, low-cost silicon solar cells. Both companies have earned space heritage on multiple satellites, with mPower now tracking over 12 years of combined on-orbit space heritage serving operational satellites.
In just the last few months, mPower and Solestial also announced $20 million and $17 million rounds, respectively, to scale production. Together, the two companies could produce more MW of silicon solar cells than the entire industry produces of traditional GaAs cells combined within the next few years. Their recent fundraising rounds are bets on capturing a fundamental shift in the space industry from exquisite, long-duration assets to mass-produced, replenishable constellations.
Customers are already making the switch, putting a premium on reliable availability. Over time, as silicon cell technology advances, silicon solar cells could match the efficiency of GaAs cells, eliminating any advantage for what’s been the industry standard.
While silicon solar cells cannot yet replace GaAs cells in all cases, over time the industry’s shift toward silicon will accelerate. Increasing demand for satellites, the supply chain risks of using GaAs cells, and the improving efficiency of silicon ensure this trend will continue. Still, today, access to GaAs cells slows satellite production. The U.S. government can take key steps to alleviate this bottleneck as quickly as possible.
The U.S. government is a key customer of solar cells for space. As companies like mPower and Solestial improve their offerings and gain longer track records in space, customers like the Space Force and NASA should issue cell chemistry agnostic requirements for large constellations like SDA Tranche 1 and 2, as well as Golden Dome constellations. This will allow prime contractors to use GaAs cells as needed but gradually switch to silicon solutions as those solutions become more proven in space. These requirements should specify performance and efficiency, rather than a particular material.
Still, access to GaAs cells will remain essential for certain satellites with high priority missions, at least for the next few years. GaAs cells are also essential for other national security missions, including missile detection radars. The White House should coordinate with the DoD and the Intelligence Community (IC) to quantify the importance of gallium in the context of export control negotiations with China. Doing so will ensure the costs of losing access to a critical mineral like gallium are worth the expanding export control regime on high performance chips.
Over time, the U.S. will need to avoid relying on China altogether for a mineral that’s essential for various national security applications. Shifts to silicon solar cells for certain applications will help, but in the long term, the U.S. should consider onshoring gallium mining and processing alongside other critical minerals. U.S. Critical Minerals Corp, a Salt Lake City based mining company, discovered a large gallium deposit just last year.
As the space industry enters a new era of mass production and proliferated constellations, solar power, once taken for granted, is now a primary constraint. The GaAs shortage, sharpened by China’s export controls, has revealed deep vulnerabilities in U.S. supply chains and strategic dependencies. Fortunately, innovation in silicon-based solar technology offers a path forward — one that is more scalable, resilient and geopolitically secure. By supporting this transition through forward-looking procurement policies, diversified sourcing strategies and investment in domestic capabilities, the U.S. and its allies can ensure that power in space becomes as accessible and reliable as launch itself.
Matt Kaplan is an Investment Analyst at Shield Capital, an early stage venture firm investing at the nexus of commercial and national security technologies.
David Rothzeid is a Principal at Shield Capital. He served in the United States Air Force as an acquisition officer for over a dozen years and is still a reservist at the Pentagon.
SpaceNews is committed to publishing our community’s diverse perspectives. Whether you’re an academic, executive, engineer or even just a concerned citizen of the cosmos, send your arguments and viewpoints to opinion@spacenews.com to be considered for publication online or in our next magazine. The perspectives shared in these opinion articles are solely those of the authors.
Matt Kaplan is an Investment Analyst at Shield Capital, an early stage venture firm investing at the nexus of commercial and national security technologies. More by Matt Kaplan
David Rothzeid is a Principal at Shield Capital. He served in the United States Air Force as an acquisition officer for over a dozen years and is still a reservist at the Pentagon. More by David Rothzeid
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