Jeff Thornburg helped build Raptor at SpaceX. Now he’s building something new: a spacecraft designed for rapid maneuverability across orbits powered by solar thermal propulsion.

In this episode of Valley of Depth, we get into the technical, strategic, and commercial implications of in-space mobility and why it matters now. Topics include:

• The hardest parts of building a rocket engine (and why most startups get it wrong)
• The origins of the Raptor engine and lessons from SpaceX
• Why Portal is betting on solar thermal propulsion
• How Supernova enables fast, responsive movement across LEO, MEO, and GEO
• The case for refueling in orbit and designing without dependencies
• Why defense needs faster spacecraft and what commercial use cases follow
• How Thornburg sees Starship changing the economics of space

and much more…

• Chapters •

00:00 – Intro

01:44 – What drew Jeff to creating engines?

05:13 – Why is building rocket engines still so difficult?

11:50 – Jeff's time at SpaceX

17:52 – Stratolaunch and Commonwealth Fusion and why Jeff moved on

22:50 – Origin of Portal

25:25 – Commercial use case

27:00 – 5 year vision for Portal's architecture

32:01 – Pricing

34:52 – Solar thermal propulsion

38:14 – What comes after Portal's Supernova?

41:15 – Customer traction and Supernova flight

45:44 – Competition in solar thermal propulsion

49:20 – Fundraising prior to the first launch

51:18 – Portal in the next 10 years

54:53 – State of Starship

• Show notes •

Jeff’s socials — https://x.com/JeffThornburg

Antares’ socials — https://x.com/PortalSpaceSys

Antares’ website — https://www.portalsystems.space/

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

In the wake of new executive orders elevating nuclear energy as a national security priority, there’s growing momentum—and urgency—behind advanced fission technologies. Few are better positioned to talk about this shift than Jordan Bramble, co-founder and CEO of Antares Nuclear, a startup building microreactors for defense and space.

In this episode of Valley of Depth, we explore the strategic, technical, and geopolitical dimensions driving the nuclear renaissance. We cover:

• Why microreactors are built for strategic energy and not just the grid

• The real story behind public support for nuclear energy

• How Antares plans to deploy sub-megawatt nuclear systems on U.S. military installations

• The challenges of fuel supply, regulation, and capital

• Why China is pulling ahead and what the U.S. must do to catch up

• Nuclear-powered space assets and propulsion

• Why Jordan believes venture-scale outcomes are coming to nuclear energy

• Chapters •

00:00 - Intro
00:56 - Payload Pro
01:39 - State of fission
03:38 - Is renewed nuclear interest driven by political or environmental factors?
05:23 - Are small modular reactors (SMRs) going to replace large, conventional nuclear reactors?
07:31 - Is nuclear still a controversial topic?
09:27 - Cultural legacy of nuclear in media
11:49 - Antares and how Jordan got into nuclear
14:16 - What does 1 Megawatt mean?
15:53 - Game changing environments for Antares's SMR
19:30 - Terrestrial business model
20:39 - Nuclear fuel supply chain
21:35 - Current state and future prediction of fuel pipeline
23:42 - Safety in contested environments
26:49 - Hardest technical challenges
29:52 - What will it take to get to their first electron
31:23 - Competition
34:27 - US vs its adversaries
36:29 - Navigating regulatory guidelines
38:10 - Impact of Trump's Executive Orders
40:03 - NRC
41:12 - Are we living in a VC renaissance for nuclear?
44:05 - What drives Jordan to work on nuclear?
46:30 - For those afraid of nuclear

• Show notes •

Jordan’s socials — https://x.com/jordanbramble

Antares’ socials — https://x.com/AntaresNuclear

Antares’ website — https://boomsupersonic.com/

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com

• Ignition: www.ignition-news.com

• Tectonic: www.tectonicdefense.com

In a major shift, the U.S. government is moving to overturn a 50-year ban on civilian supersonic flight over land—a regulation that’s defined the boundaries of commercial aviation since 1973. It’s a pivotal moment for aerospace, and a timely one for this conversation with Blake Scholl, founder and CEO of Boom Supersonic.

In this episode of Valley of Depth, we dive into the political, technical, and economic forces driving the return of high-speed air travel. We cover:

• Why the U.S. banned supersonic flight and why that’s finally changing
• How Boom plans to make supersonic flight sustainable and commercially viable
• The decision to build a new engine in-house after legacy players stepped away
• What the real economics of airline orders look like and who’s truly onboard
• How regulatory shifts, geopolitical dynamics, and climate pressure intersect
• And why Blake believes faster travel isn’t just a luxury, it’s a necessity

…and much more.

• Chapters •

00:00 - Intro
01:07 - Payload Pro ad
01:49 - Supersonic ban repeal
03:48 - Why were supersonic planes banned in the first place?
08:47 - Next steps for supersonic
11:10 - How long until we get a supersonic jet?
12:34 - Why Blake started Boom
16:00 - Why now for supersonic?
18:23 - State of China's commercial supersonic space
19:48 - Boom Supersonic's engines
23:56 - When will the Symphony Engine having a working model?
29:09 - Engineer challenges beyond the engine
29:52 - Engineering the quiet boom
33:49 - What does a sonic boom sound and feel like?
36:11 - Vertical integration
38:05 - Routes that Overture would fly first
38:47 - How much capital would Boom Supersonic need to build their first plane?
40:12 - What did Aerion get wrong?
44:22 - What will the supersonic competition look like?
45:35 - Northrop Grumman partnership
49:58 - Blake's mission behind Boom
52:60 - What will Boom look like in the future?

• Show notes •

Boom Supersonic’s socials — https://x.com/boomaero

Blake’s socials — https://x.com/bscholl

Boom’s website — https://boomsupersonic.com/

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

If the next great war is fought in space, Even Rogers wants the U.S. to be ready. On this episode of Valley of Depth, the True Anomaly CEO and former Air Force weapons officer joins us to break down how he’s building autonomous systems for space superiority and why space is the next warfighting domain. A graduate of the Air Force Weapons School, Even brings rare tactical and strategic insight into how the U.S. must fight and win in orbit.

In this episode, we unpack the doctrine, technology, and strategy shaping the next phase of military competition in space. We cover:

•  Why 2007 was the turning point for space as a warfighting domain
• How to think about offense, deterrence, and domain control in orbit
• What the Space Force needs—and why $60B is the real number
• The role of private industry vs. the primes in defense innovation
• Golden Dome, missile defense, and the future of space-based interceptors

…plus how we may one day have Guardians stationed permanently in space.

Check out Valley of Depth #007 on YouTube, Apple, or Spotify.

• Chapters •

00:00 - Intro

00:57 - Payload Pro

01:39 - True Anomaly's mission

02:51 - How Even started the company

04:02 - $220m Series C

05:48 - When did space become a place to defend?

09:20 - The challenge to US space dominance

11:16 - What made Even realize that the US was unprepared?

16:05 - What does space superiority look like?

17:49 - What does space warfare actually mean?

21:48 - The R&D the Space Force needs

24:01 - What it meant to form the Space Force

27:11 - The cultural shift on the Space Force

30:49 - Current US Space capabilities and gaps

32:44 - Why was the Space Force budget cut despite its importance?

35:06 - Primes and the US's space capabilities

37:12 - Procurement for the space domain

41:29 - Space components of the Golden Dome

43:35 - Phases of a ballistic missile

44:56 - Intercepting missiles at its boost phase

46:15 - What to prioritize today for space superiority

49:20 - Guardians in space

51:20 - Moon & Mars

52:40 - Lessons learned for the next True Anomaly mission

56:01 - What is the strategic impact True Anomaly is hoping to have?

57:31 - Will NASA blur the lines between civil and military?

• Show notes •

True Anomaly’s socials — https://x.com/the_trueanomaly

Even’s socials — https://x.com/jollyrogersta

True Anomaly’s website — https://www.trueanomaly.space/

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

This week on Valley of Depth, we’re joined by Paul Lwin, co-founder and CEO of Havoc AI—a builder of integrated hardware, software, and logistics that enables collaborative, autonomous maritime operations. A former Navy test pilot and electronic warfare officer, Paul saw firsthand the strategic challenge posed by China’s industrial scale in the Pacific and set out to build an asymmetric answer.

In this episode, Paul shares how Havoc went from pre-seed to delivering 40+ autonomous vessels in just 18 months, what it takes to deploy real autonomy in contested environments, and why the Navy forced them to sell their early prototypes. We also cover:

• Why Havoc built 12 USVs with just 5 people and a $1.2M pre-seed
• How Ukraine’s naval tactics shifted the Pentagon’s mindset
• The difference between platform, mission, and decision autonomy
• Why primes can’t match Havoc’s pace—or price point
• How Replicator changed the rules for startup engagement with DoD
• What it’ll take to get thousands of autonomous boats into the Pacific

…and much more.

Check out VoD #006 on…YouTube, Apple, or Spotify.

• Chapters •

0:00 - Intro

1:07 - Company Mission & Vision

3:43 - DoD Autonomous Exercise Demonstration

6:41 - Funding to Demo Timeline

8:43 - Founding Team & Headquarters

10:19 - Market Demand for Autonomous Maritime Tech

12:42 - Vertical Integration Strategy

14:30 - US Navy Capability Gaps

16:24 - Geopolitics & Business Strategy

17:40 - Product Architecture Roadmap

21:21 - Commercial Market Potential

24:05 - Autonomy Level Achieved

26:48 - Contested Environment Design

28:24 - Next Frontier in Naval Tech

30:04 - Scaling for DoD Requirements

32:09 - Competitive Differentiation

33:48 - Prime Contractor Advantages

35:21 - Replicator Initiative Impact

36:19 - Buyer Incentive Structures

37:44 - Desired Policy Changes

39:09 - Scaling Funding Requirements

40:35 - Defining Mission Success

• Show notes •

Havoc’s socials — https://x.com/HavocAi_USV

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

This week on Valley of Depth, we’re joined by Marc Allen, CEO of Electra and former Chief Strategy Officer at Boeing. After nearly two decades at one of aerospace’s most iconic companies, Marc stepped away—and then doubled down—on aviation with a bold bet: a hybrid-electric aircraft that takes off in 150 feet, carries 1,000 pounds, and can land almost anywhere.

In this episode, Marc breaks down why the future of flight is short-runway, low-noise, and mission-flexible—and how Electra’s EL-9 is carving out a new category of aircraft entirely. We also get into:

• Why hybrid-electric beats all-electric
• How Electra won over DOD and NASA
• The military’s growing demand for quiet, flexible airlift
• Why rotorcraft are ripe for disruption
• The company’s $13B+ order book
• And how Marc thinks about scaling from Boeing to startup

• Chapters •

0:00 - Episode Introduction

0:58 - Marc's Transition: Boeing to Electra

3:13 - Electric Propulsion Breakthrough Moment

4:29 - Electra's Core Technology

5:17 - Importance of Electric Aircraft

6:52 - EL9 vs Helicopter Comparison

7:30 - Safety Features

10:06 - Automation Capabilities

10:54 - Charging Infrastructure

11:18 - Technology Maturity Level

12:41 - EL9 Market Potential

15:57 - Current Demand & Use Cases

18:17 - Operator Economics

20:20 - Air Force Partnership

21:16 - Defense Applications

23:43 - Autonomous Potential

24:41 - Future Aircraft Versions

26:08 - NASA's Interest

26:47 - Civil vs Defense Models

27:21 - Manufacturing Process

29:15 - Certification Timeline

31:32 - Key Challenges

34:24 - Fundraising Status

36:32 - Commercialization Costs

38:00 - Upcoming Milestones

38:24 - Team Size

39:03 - Scaling From Large to Small Company

41:15 - OEM Strategy

41:50 - 10-Year Vision

42:44 - Marc's Personal Interests

43:40 - Pilot Training Requirements

• Show notes •

Electra’s socials — https://x.com/ElectraAero

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

This week on Valley of Depth, we’re joined by Erik Kriessmann, Partner at Altimeter – the $10B crossover firm known for backing generational companies across tech, defense, and space. From sourcing early-stage deals to helping build world-class teams, Erik’s path into venture started with a deep focus on talent, giving him a rare edge in identifying high-potential founders and building lasting partnerships.

In this episode, Erik shares how Altimeter thinks about concentrated investing, why the firm bets big on supercycles, and what it takes to earn a seat at the table with the best teams in tech. We also cover:

• How Altimeter defines a “supercycle”
• The firm’s bets across AI, defense, and aerospace
• What separates a good founder from a great one
• Why Altimeter backed Anduril and K2
• His take on the Mars hype (spoiler: not yet)
• And how SpaceX changed the game for everyone

…and much more.

• Chapters •

0:00 - Intro

1:05 - Did Erik know he was going to be an investor?

1:44 - Erik's career journey

9:05 - Going from building talent teams to working with CEOs directly

12:07 - The investment philosophy core to Altimeter's growth

15:31 - Public vs private side of Altimeter

16:42 - How decisions get made

19:35 - What is today's super cycle?

21:14 - What technologies is Altimeter currently excited about?

22:40 - What does Erik look for in a founder?

24:25 - How do geopolitics weigh in on Altimeter's investments?

27:20 - Space super cycle

28:56 - What is Erik on the lookout for in the space industry

31:04 - How about Mars?

33:42 - Why did Altimeter first invest in Anduril?

36:09 - Navigating the DoD procurement process

37:50 - Expanding margin with the government customer

40:27 - Are we in a defense tech bubble?

41:56 - Has Altimeter invested in pure play defense names outside of Anduril?

44:03 - Exit paths for Altimeter's investments

45:34 - Foreign defense investment opportunities

47:34 - What would Erik be doing if he wasn't an investor?

49:42 - What's Erik listening to these days?

• Show notes •

Erik’s socials — https://x.com/ekriessmann

Brad’s socials — https://x.com/altcap

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

This week on Valley of Depth, we’re joined by Christian Garcia, Partner at Breakthrough Energy Ventures — the Bill Gates-backed climate fund investing in bold technologies to accelerate the energy transition across every sector of the economy. With portfolio companies tackling everything from geologic hydrogen to reusable rockets, BEV is redefining what it means to scale climate impact through hard tech.

In this conversation, Christian shares how BEV thinks about breakthrough innovation, what makes a venture-backable climate solution, and why some of the most disruptive ideas look impossible—until they’re not. We also get into:

• BEV’s origin story
• How climate and national security are converging
• The firm’s approach to fusion, hydrogen, and aerospace
• Why BEV backed both CFS and Pacific Fusion
• What drew Christian to space — and Stoke Space in particular
• And his take on what’s really being underestimated in climate today

• Chapters •

0:00 - Intro

1:04 - What is Breakthrough Energy Ventures and how is it different from a typical fund?

2:26 - BEV's investors and why are they interested

5:45 - Is there a defense interest at BEV?

9:00 - How did Christian get into this space?

11:13 - What is BEV currently focused on?

14:17 - What type of breakthrough is BEV investing in and when?

17:16 - Firms BEV co-invests with

18:34 - Seed and Pre-seed investing

25:43 - What is the goal of investing in multiple fusion companies?

30:23 - How does space fit in BEV's climate portfolio?

34:23 - How do you separate bold vision from wishful thinking?

38:03 - Balancing science and storytelling

42:08 - Tech that Christian has passed on

45:37 - A BEV company that Christian thinks will shock the world with its success

48:48 - What are some common misconceptions about climate tech?

51:28 - Rapidfire questions

• Show notes •

BEV’s website — https://www.breakthroughenergy.org/our-work/breakthrough-energy-ventures/

BEV’s socials — https://x.com/Breakthrough

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

This week on Valley of Depth, we’re joined by Tejpaul Bhatia, the newly appointed CEO of Axiom Space — a company building one of the first commercial space stations and leading private human spaceflight missions to low Earth orbit. The company is gearing up for Ax-4, Axiom’s fourth mission to the ISS, which will fly astronauts from Poland, Hungary, and India under the command of Axiom astronaut Peggy Whitson.
 

In his first interview (and podcast) as CEO, Tejpaul shares what the leadership transition means for Axiom, why he sees the company as a “forever business,” and how he plans to scale its station, suits, and astronaut programs into a thriving orbital economy. We also get into:

• Tejpaul’s journey from startup founder to Axiom CEO
• The state of the space station market and the case for demand
• What investors misunderstand about orbital infrastructure
• Axiom’s shifting revenue mix and modular station roadmap
• His take on the CLD program and U.S. industrial strategy
• How Tejpaul thinks about scaling trust, culture, and ambition in space

• Chapters •

00:00 Intro

00:59 Tejpaul's transition into the CEO role

03:25 Tejpaul's background before Axiom

08:03 Reaction to being offered CRO role

10:50 Previous CEO's departure

12:57 Preserving vs evolving at Axiom

14:23 Initial priorities as CEO

19:06 Free-flying space station market

24:37 Number of future space station operators

27:06 Science projects vs commercial viability

32:44 Current and future revenue streams

38:11 Commercial Low-Earth Orbit Destination (CLD)

41:21 Moving beyond NASA dependence

45:45 Technical roadmap

47:19 Astronaut program pricing

53:21 What investors miss about stations

56:04 Capital requirements and fundraising

01:00:07 Cost of first station

01:01:35 Axiom & SpaceX relationship

01:04:40 Tejpaul's personal interests

• Show notes •

Axiom’s website — https://axiomspace.com/

Axiom’s socials — https://x.com/Axiom_Space

Mo's socials — https://twitter.com/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com
• Tectonic: www.tectonicdefense.com

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 Intro

00:52 What inspired Bryan to leave SpaceX and start Castelion?

03:06 Non-nuclear deterrence

05:15 How SpaceX's culture influenced Castelion

07:44 Current team size

08:07 Cultural shift in defense hiring

10:04 Hypersonic missile advantages

12:03 US vs China capabilities

13:32 Tradeoffs vs exquisite systems

16:08 What's behind Bryon

18:02 Recent test results

20:54 Iterating safely

24:27 Castelion's DoD buyer

26:56 Navigating defense acquisition

32:11 Championing innovation

35:17 The Golden Dome concept

37:10 Requirements for Golden Dome

39:21 Startups vs primes race

40:49 Scaling missile production timeline

42:48 European market potential

44:19 Competition with defense primes

45:49 Capital requirements

47:26 Company vision

49:13 World impact if successful

50:48 Next milestones

52:14 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/itsmoislam

Payload’s socials — https://twitter.com/payloadspace / https://www.linkedin.com/company/payloadspace

Ignition’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.com
• Ignition: www.ignition-news.com

Tectonic: www.tectonicdefense.com