This press release features multimedia. View the full release here: https:\/\/www.businesswire.com\/news\/home\/20260604394501\/en\/<\/a><\/p>\n \n\u201cControlling our supply chain is a core part of how York delivers for our customers, and space solar has been a critical gap the industry has largely ignored,\u201d said Dirk Wallinger, CEO of York. \u201cSolestial\u2019s solar cells are produced in the U.S. and will ultimately source raw material from U.S. suppliers creating a complete U.S. solar cell production ecosystem and their solar cells are proven to self-anneal radiation damage on orbit. This acquisition positions York to meet the program timelines our customers require, without the supply chain vulnerabilities that put others at risk.\u201d<\/p>\n \nThe geopolitical risk embedded in the industry\u2019s supply chain is significant. China controls 99% of the gallium and more than 60% of the germanium required for legacy III-V solar cells, and 93% of the polysilicon used in terrestrial solar panels is produced in China. York believes current solar panel designs will not be sustainable in the future, particularly given the large driving demand required for proliferation of systems. With trade restrictions escalating, satellite manufacturers without a domestic source face a growing vulnerability, one York has moved decisively to address.<\/p>\n \nSolestial\u2019s technology is engineered specifically for the space environment, differentiating it from the terrestrial silicon cells other new entrants are attempting to fly. With approximately 95% of its supply chain already U.S. based, Solestial draws on domestic sources rather than the Chinese-controlled inputs that put others in the industry at risk.<\/p>\n \n\u201cJoining York accelerates everything we set out to build,\u201d said Margo de Naray, CEO of Solestial. \u201cWe\u2019ve proven on orbit that our self-healing solar cells outlast terrestrial solar alternatives. Now we\u2019re positioned to scale that technology with a U.S.-sourced supply chain and deliver it at the volume the industry needs.\u201d<\/p>\n \nSolestial\u2019s differentiated radiation-curing technology sets it apart from every other space solar option on the market. Its thin and flexible silicon solar cells self-heal radiation damage at operating temperatures as low as 65\u00b0C as independently verified by the French Alternative Energies and Atomic Energy Commission (CEA). On-orbit telemetry confirmed that after one year in LEO, Solestial cells showed no additional degradation compared to adjacent III-V multijunction cells, a result terrestrial silicon cannot replicate. Legacy III-V solutions also carry lead times exceeding two years and face challenges to scale to meet accelerating demand.<\/p>\n \nThe acquisition advances York\u2019s strategy of owning critical subsystems rather than sourcing them from constrained, foreign-dependent supply chains, a competitive advantage that York expects will directly benefit customers across national security, civil, and commercial programs. Solestial will operate as a wholly owned subsidiary, continuing to supply solar technology to external customers while deepening integration across York\u2019s spacecraft portfolio. Together, York and Solestial are positioned to meet the power demands of next-generation missions with technology that is flight-proven, scalable, and significantly reduces geopolitical supply chain risk that defines the rest of the market.<\/p>\n \nYork closed the acquisition on June 4, 2026 with the issuance of 1,703,577 York shares using a negotiated value of $34.00 per share and paid with a mix of cash and stock for a purchase price of approximately $67 million paid to the sellers at closing. York shares were issued pursuant to one or more exemptions from registration under the Securities Act of 1933, as amended, including those under Section 4(a)(2) thereof or Regulation D promulgated thereunder.<\/p>\n About York Space Systems<\/b><\/p>\n York Space Systems<\/b><\/a> (NYSE: YSS) is a leading, U.S.-based national defense and commercial prime providing a comprehensive suite of mission-critical solutions for national security, government, and commercial customers. York is one of the only space and defense primes with proprietary hardware and software capabilities designed to address customers\u2019 complex mission requirements across the critical elements of the entire space ecosystem throughout the mission lifecycle. York is purpose built to address evolving national security space challenges and to adapt to the ongoing shift in the U.S. government\u2019s mission needs and procurement processes.<\/p>\n About Solestial<\/b><\/p>\n \nSolestial exists to deliver abundant energy in space. The company\u2019s breakthrough technology is a silicon solar cell engineered for space to self-cure radiation damage under sunlight at operating temperatures as low as 65\u00b0C. Solestial solar cells are packaged in an ultrathin, low-mass, flexible solar power module designed to withstand up to 10 years in a variety of destinations in space. The flexible solar power modules can be produced on automated machines resulting in costs lower than traditional III-V multijunction solar products.<\/p>\n \nFrom today\u2019s satellite constellations and research projects to tomorrow\u2019s lunar settlements and services in space, Solestial\u2019s innovative technology represents a paradigm shift for space solar; an affordable, scalable solution to power sustained development. Solestial is a U.S. company manufacturing solar cells and flexible solar power modules in Tempe, Arizona. To learn more, visit the Solestial website<\/a> and follow Solestial on social media<\/a>.<\/p>\n Forward-Looking Statements<\/b><\/p>\n \nThis press release contains \u201cforward-looking statements\u201d within the meaning of, and we intend such forward-looking statements to be covered by, the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified. In some cases, you can identify forward-looking statements by terminology such as \u201canticipate,\u201d \u201cbelieve,\u201d \u201ccould,\u201d \u201cemerging,\u201d \u201cexpand,\u201d \u201cexpect,\u201d \u201cfeasibility,\u201d \u201cintend,\u201d \u201cmay,\u201d \u201cobjective,\u201d \u201cplan,\u201d \u201cpotential,\u201d \u201cshould,\u201d \u201cwill,\u201d \u201cwould,\u201d or the negative of these terms or other comparable terminology. In particular, statements about the acquisition of Solestial, including expected benefits of, and opportunities created by, the acquisition, the future capabilities of Solestial and our capabilities, following the proposed acquisition, market demand, our growth strategy and our expectations, beliefs, plans, strategies, objectives, prospects, assumptions, or future events or performance contained in this press release are forward-looking statements.<\/p>\n \nFactors that could cause actual results to differ materially from those expressed or implied by the forward-looking statements include: cost overruns on our contracts, including before final receipt of a contract; significant competition in the global space and satellite market; any failure of our spacecraft systems and related software to operate as intended, resulting in warranty claims for product failures, schedule delays or other problems with existing or new products; our revenue, results of operations and reputation may be negatively impacted if our products contain defects or fail to operate in the expected manner; our failure to establish and maintain important relationships with government agencies and prime contractors; the scarcity or unavailability of critical components used to manufacture our products or used in our development programs; disruptions in U.S. government operations and funding and budgetary priorities of the U.S. government; the inability to comply with any of our contracts or meet eligibility requirements to obtain certain government contracts; and the other factors set forth in our filings with the Securities and Exchange Commission. You should not place undue reliance on these forward-looking statements, which speak only as of the date stated, or if no date is stated, as of the date of this press release and the related conference call. Actual results may vary from the estimates provided. We undertake no intent or obligation to publicly update or revise any of the estimates and other forward-looking statements made in this press release, whether as a result of new information, future events or otherwise, except as required by law.<\/p>\n \nReferences and links to websites have been provided as a convenience, and the information contained on such websites is not incorporated by reference into this press release. York is not responsible for the content of third-party websites.<\/p>\n View source version on businesswire.com: <\/span>https:\/\/www.businesswire.com\/news\/home\/20260604394501\/en\/<\/a><\/span><\/p>\n Media Contact Investor contact KEYWORDS:<\/b> United States North America Colorado<\/p>\n INDUSTRY KEYWORDS:<\/b> Software Other Energy Hardware Alternative Energy Batteries Energy Technology Defense Satellite Government Technology Aerospace Military Manufacturing<\/p>\n![\"\"](\"https:\/\/mms.businesswire.com\/media\/20260604394501\/en\/2824048\/4\/Sputter_Tool_3_-_DSC00816.jpg\")
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Sarah Nickell
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Sarah.nickell@yorkspacesystems.com<\/a><\/p>\n
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Christopher Evenden
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ir@yorkspacesystems.com<\/a><\/p>\n
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