StarTalk Radio

The New Space Race with Jeff Thornburg

September 30, 2025

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  • Aerospace engineers are crucial for enabling scientific discovery, as they translate theoretical possibilities into functional hardware, often succeeding through a culture that accepts failure as a necessary source of data. 
  • Government-funded research and development corporations (FFRDCs) remain vital for seeding high-risk, long-term technologies that lack immediate commercial viability, such as advanced propulsion systems needed for deep space exploration. 
  • The future of space security and commerce hinges on rapid maneuverability in orbit, as current commercial and defense assets are vulnerable due to reliance on slow-moving or non-maneuverable satellites. 
  • The average citizen should care about space technology because critical infrastructure like ATMs and gas pumps rely on GPS timing, creating a vulnerability that other nations, like China, have avoided. 
  • Aerospace engineer Jeff Thornburg's company, Portal Space Systems, is developing a solar-powered thermal engine system (Supernova) that avoids combustion and oxidizers, allowing for greater fuel capacity, efficiency, and versatility in using propellants like ammonia, methane, or hydrogen. 
  • The future of space exploration hinges on accelerating AI, machine learning, and robotics to reduce the cost and pace limitations associated with keeping humans alive in space, alongside unlocking quantum physics to potentially achieve warp drive technology. 

Segments

Guest Introduction and Company Vision
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(00:00:45)
  • Key Takeaway: Portal Space Systems is developing the most rapidly maneuverable spacecraft to solve the current lack of speed in orbital movement for defense and commercial missions.
  • Summary: Jeff Thornburg’s company, Portal Space Systems, focuses on creating highly maneuverable spacecraft capable of moving between orbits like MEO to LEO in under three hours. This capability addresses the strategic need for faster response times in space, which current propulsion methods often cannot provide routinely. The long-term vision for deep space travel still involves technologies like nuclear thermal propulsion.
Engineering Career Trajectory
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(00:07:42)
  • Key Takeaway: Key technological advancements in propulsion, like the full-flow staged combustion engine, were seeded by government labs (AFRL) before being adopted by commercial entities like SpaceX.
  • Summary: Thornburg worked on developing a full-flow staged combustion engine at the Air Force Research Lab between 1999 and 2004, which seeded later engine programs, including the Raptor engine at SpaceX. He was personally recruited by Elon Musk to architect the Raptor engine system for Starship. The government’s role in funding risky R&D is necessary because private industry focuses on immediate profit and stock value.
Rocketry Philosophy: US vs. Russia
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(00:17:31)
  • Key Takeaway: The historical divergence in US and Russian rocketry stemmed from post-WWII focus: the US prioritized performance and perfection, while the Soviets emphasized reliability, part count, and manufacturability.
  • Summary: Russian rocket development, exemplified by the Soyuz capsule, focused on reliability and simplicity, leading to its enduring success as a ‘blunt instrument that works every single time.’ In contrast, the US approach, led by Von Braun’s team, prioritized performance, which sometimes resulted in overly complex systems like the Space Shuttle that were difficult and costly to refurbish.
Shift to Commercial Space Procurement
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(00:19:00)
  • Key Takeaway: NASA transitioned from owning and branding all space hardware to purchasing off-the-shelf capabilities from private companies like SpaceX, driven by massive cost reductions.
  • Summary: The incorporation of companies like Blue Origin and SpaceX in the early 2000s began shifting the paradigm, culminating when SpaceX proved it could launch payloads at significantly lower costs (e.g., $60 million per launch for Falcon 9). This cost efficiency spurred NASA’s interest in commercial crew and cargo solutions after the Space Shuttle retired.
Engineering Failure and Risk Management
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(00:26:44)
  • Key Takeaway: Effective engineering requires accepting failure as a means to rapidly identify unknown design limitations, contrasting with legacy government programs where ‘failure is not an option’ leads to infinitely high costs.
  • Summary: Unlike legacy programs that strive for zero risk at high cost, commercial startups embrace breaking hardware to learn where the design fails, accelerating the path to a working product. When failures occur, leadership must document the acceptable risk posture beforehand, distinguishing between calculated risk and incompetence.
Unit Incompatibility and Leadership Failures
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(00:35:46)
  • Key Takeaway: Major space mission failures, such as the Mars Reconnaissance Orbiter loss, result from systemic failures in system engineering, like not testing integrated components or failing to standardize units (Imperial vs. Metric).
  • Summary: The Mars orbiter failure occurred because engineers used Imperial units while scientists used metric, a problem rooted in the slow adoption of metric standards in legacy US engineering software tools. Such incidents highlight failures in system engineering execution, where integrated testing of components is neglected, regardless of the individual component’s perfection.
Consequences of Cutting R&D Funding
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(00:38:13)
  • Key Takeaway: Current cuts to NASA’s science and R&D budgets risk America’s technological leadership by causing scientists to emigrate and failing to fund the diverse research necessary for future breakthroughs.
  • Summary: The reduction in US R&D funding is causing scientists to be recruited by foreign nations, effectively plundering the country’s intellectual treasure. This trend jeopardizes America’s competitive edge, as fundamental scientific exploration must be funded broadly to yield unpredictable, high-value winners.
Space Assets and National Vulnerability
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(00:55:30)
  • Key Takeaway: The primary role of the Space Force is not offensive warfare but defending critical civilian infrastructure in orbit, such as GPS and communication satellites, upon which modern financial and logistical systems depend.
  • Summary: Adversaries will target US space assets—like GPS timing systems essential for ATMs and gas pumps—rather than traditional military targets, as this represents a critical vulnerability. Unlike China, the US has deeply integrated its financial systems with GPS, creating a strategic weakness that requires active defense in orbit.
GPS Vulnerability and National Security
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(00:57:01)
  • Key Takeaway: The US financial system’s reliance on GPS timing for functions like ATMs creates a critical vulnerability that adversaries can exploit without direct attack.
  • Summary: The average citizen should care about space technology because GPS timing underpins financial systems, including gas pumps and ATMs. The US made a deliberate choice to tie these systems to GPS, unlike China, which uses alternative timing methods. This dependence creates a fundamental vulnerability in national infrastructure.
Orbit Bullying Tactics
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(00:57:39)
  • Key Takeaway: Adversaries are employing non-destructive tactics like ‘orbit bullying’—using nearby satellites to harass US assets with electromagnetic fields—to prematurely deplete satellite fuel reserves.
  • Summary: Satellites currently lack meaningful self-defense capabilities against threats in orbit. Adversaries may deploy satellites to nestle next to US assets and harass them electromagnetically. This forces US satellites to maneuver for operability, consuming station-keeping fuel and reducing their overall lifespan without firing a weapon.
Portal Space Systems Company Origin
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(00:59:16)
  • Key Takeaway: The name ‘Portal Space Systems’ was inspired by the portal gun concept from the animated series Rick and Morty.
  • Summary: The CEO of Portal Space Systems shared the origin of the company name. The inspiration came from watching Rick and Morty with his daughter. The name references the portal gun from the show.
Supernova Propulsion System Details
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(00:59:58)
  • Key Takeaway: The Supernova propulsion system uses concentrated solar energy and an innovative heat exchanger to avoid combusting liquid propellants, enabling higher thrust and carrying twice the fuel by eliminating the need for an oxidizer.
  • Summary: The Supernova system utilizes concentrated solar energy to drive a thermal engine cycle without combustion. This design allows for fewer parts, increased efficiency, higher thrust, and the ability to carry twice as much fuel because an oxidizer is not required. The thermal engine is versatile, capable of using ammonia as a baseline fuel or switching to methane or hydrogen for deep space missions.
Living Off the Land Engineering Philosophy
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(01:01:54)
  • Key Takeaway: The engineering philosophy for deep space missions should prioritize ’living off the land’ (In-Situ Resource Utilization or ISRU) rather than carrying all necessary supplies from Earth.
  • Summary: The speaker advocates for a ’live off the land’ approach for space exploration, stating that taking everything with us signifies engineering failure. NASA’s term for this is In-Situ Resource Utilization (ISRU), which the speaker suggests rebranding to the more marketable ‘Living off the Land’ (LOTL). Additive manufacturing companies, like one in Florida called Admin, support this by enabling the printing of necessary tools once on Mars.
Software-Definable Spacecraft Platform
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(01:02:51)
  • Key Takeaway: Portal Space Systems aims to provide versatile spacecraft that offer software-definable power and data connections, allowing payloads (cameras, robot arms) to be easily integrated like Lego bricks.
  • Summary: The company focuses on payload flexibility by offering a spacecraft platform that can supply power and data to any attached mission hardware. This contrasts with current industry practice where entire satellites, including the payload, are bespoke and one-off builds, which is expensive and risky. This modular approach is described as ’engineering heaven’ because it meets diverse customer needs.
Future Engineering Goals: AI and Quantum
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(01:04:37)
  • Key Takeaway: The two primary engineering goals for the future are accelerating AI/ML for robotic exploration to bypass human life support constraints and unlocking quantum physics for propulsion technologies resembling warp drives.
  • Summary: Accelerating AI and machine learning is crucial to move robots into space for heavy lifting, as the cost of keeping humans alive slows exploration. This robotic exploration will teach engineers what is needed to safely keep humans alive later. Furthermore, understanding the quantum world is seen as the linchpin for manipulating the space-time continuum, potentially leading to warp drive technology by 2063.
The Role of Constraints in Engineering
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(01:09:47)
  • Key Takeaway: Engineers derive their ingenuity and make discoveries by solving problems within defined constraints of time, budget, and specifications, rather than being given open-ended mandates.
  • Summary: Scientists characterize problems, but engineers are required to solve them, making them essential for civilization’s future. Engineers thrive when given specific constraints, such as a timeframe, budget, and technical specifications. Without these limitations, engineers struggle to focus their ingenuity.
Commercial Space Travel Holy Grails
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(01:08:14)
  • Key Takeaway: The ultimate commercial achievement is making cislunar space (the region between Earth and the Moon) routine, while a personal goal is suborbital travel enabling 45-minute transit between any two points on Earth.
  • Summary: Chuck Nice’s ultimate goal is suborbital travel allowing transit between any two points on Earth in under 45 minutes, such as a lunch meeting in Tokyo. Jeff Thornburg’s holy grail is making travel to any orbit between Earth and the Moon so routine that visiting the Moon is not considered a significant emotional event. This means cislunar space becomes as commonplace as traveling to Poughkeepsie.