The recent revolution in artificial intelligence (AI), together with advances in telescopes and computing, has opened new frontiers for astronomy data processing and analysis. Meanwhile the rapidly increasing amount and complexity of information has created fresh barriers to access and explore data. The NSF-Simons AI Institute for Cosmic Origins (CosmicAI) will grow transformative AI advances with the overarching goal to increase accessibility of astronomy data and knowledge for researchers, students, and the general public. CosmicAI will leverage partnerships between academia, government, and industry to develop capabilities that enable astronomical researchers to conceptualize, define, and execute research projects via trustworthy, efficient, robust, and explainable AI methods. By building next-generation AI tools the Institute will accelerate discoveries related to the most basic human question: Where do we come from? To advance participation by the full astronomical community, CosmicAI will develop an extensive, multi-tiered AI educational program and launch an AI data platform to host data and support AI analysis tasks.<br/><br/>The NSF-Simons AI Institute for Cosmic Origins (CosmicAI) will grow transformative AI advances, reform research workflows, and increase astronomy and AI accessibility through developments in four fundamental AI pillars: trustworthiness, robustness, explainability, and efficiency. CosmicAI will advance foundational generative AI and democratize data and knowledge access by developing an AI Copilot model built on astronomical data archives. In preparation for the prodigious data production of the next-generation observing facilities, CosmicAI will advance AI techniques for the analysis of large-scale, high-dimensional data in order to optimize the processing, delivery, and analysis of astronomical observations. CosmicAI will boost the transparency of AI methods by developing techniques for explainable inference and applying them to interrogate the nature of dark matter. Finally, CosmicAI will extend AI techniques to confront computational bottlenecks and accelerate current modeling capabilities, including tackling the formation of complex molecules, a process that underpins problems spanning galaxy formation to habitability. CosmicAI will serve as a nexus point to boost participation in AI advances: CosmicAI will launch the first AI-Astronomy online transcripted certificate program, distribute AI educational material in bootcamps, summer schools, and online education repositories, and launch an AI Data Platform to host astronomical data and support AI analysis tasks to enable the full community to engage with AI advancements. This institute is jointly funded by the NSF and The Simons Foundation.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.