Hypersonic Power Play, with Bryon Hargis (CEO of Castelion)

We’re excited to launch Valley of Depth, our new podcast taking the place of our beloved (formerly known as) Pathfinder (RIP) podcast. Valley of Depth is about the technologies that matter—and the people building them. We talk to founders, investors, government officials, and military leaders shaping the future of national security and deep tech. From breakthrough science to strategic policy, we dive into the high-stakes decisions behind the world’s hardest technologies. In our inaugural episode, EP 001, we’re joined by Bryon Hargis, co-founder and CEO of Castelion, a venture-backed defense startup building affordable, mass-producible hypersonic missile systems for the U.S. and allied militaries. Castelion, founded by former SpaceX engineers, is taking a vertically integrated, fast-iteration approach to strike weapons—redefining how complex defense hardware is built. In this episode, we unpack the story behind Castelion’s formation, the rising hypersonic threat from China, how startups are challenging the dominance of traditional primes—and much, much more… • Chapters •00:00 Intro00:52 What inspired Bryan to leave SpaceX and start Castelion?03:06 Non-nuclear deterrence05:15 How SpaceX's culture influenced Castelion07:44 Current team size08:07 Cultural shift in defense hiring10:04 Hypersonic missile advantages12:03 US vs China capabilities13:32 Tradeoffs vs exquisite systems16:08 What's behind Bryon18:02 Recent test results20:54 Iterating safely24:27 Castelion's DoD buyer26:56 Navigating defense acquisition32:11 Championing innovation35:17 The Golden Dome concept37:10 Requirements for Golden Dome39:21 Startups vs primes race40:49 Scaling missile production timeline42:48 European market potential44:19 Competition with defense primes45:49 Capital requirements47:26 Company vision49:13 World impact if successful50:48 Next milestones52:14 Story behind the name • Show notes •Castelion’s website — https://www.castelion.com/Bryon’s socials — https://x.com/hargsb Mo's socials — https://twitter.com/itsmoislamPayload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspaceIgnition’s socials — https://twitter.com/ignitionnuclear / https://www.linkedin.com/company/ignition-nuclear/Tectonic’s socials  — https://twitter.com/tectonicdefense / https://www.linkedin.com/company/tectonicdefense/Valley of Depth archive — Listen: https://pod.payloadspace.com/ • About us •Valley of Depth is a podcast about the technologies that matter — and the people building them. Brought to you by Arkaea Media, the team behind Payload (space), Ignition (nuclear energy), and Tectonic (defense tech), this show goes beyond headlines and hype. We talk to founders, investors, government officials, and military leaders shaping the future of national security and deep tech. From breakthrough science to strategic policy, we dive into the high-stakes decisions behind the world’s hardest technologies.Payload: www.payloadspace.comIgnition: www.ignition-news.comTectonic: www.tectonicdefense.com