Space isn’t just rockets anymore — it’s becoming the backbone of the global economy.
In this debut episode of The Long Frontier, hosts Brannon Jones and Abe Murray dive deep into the rapidly evolving space industry — from falling launch costs to the rise of a true orbital economy. Joined by propulsion expert Jeff Thornburg, they explore what it will take to unlock the next era of space infrastructure, mobility, and exploration.
Jeff Thornburg is an aerospace propulsion expert and the CEO of Portal Space, with over 30 years of experience across NASA, defense, and commercial space. He played a key role in the development of next-generation propulsion systems (including work related to SpaceX’s Raptor engine) and is now focused on advancing propulsion technologies that enable scalable movement and logistics in space.
Jeff references the iconic “Mr. Fusion” reactor from Back to the Future — a fictional device that turns waste into energy. Learn more about it here: https://www.entertainmentearth.com/news/use-mr-fusion-time-travel-clean-energy/
Follow and connect with Brannon Jones & Abe Murray: https://x.com/thelongfrontier
The Long Frontier explores the technologies shaping the next 30 years of human civilization — going deep on the science, engineering tradeoffs, and market dynamics behind the most important innovations.
Anode — Positive electrode in an electric thruster; in a Hall thruster it injects propellant (usually xenon) and collects electrons.
Cathode — Negative electrode; emits electrons to ionize propellant and neutralize exhaust.
Chemical Propulsion — Uses combustion of fuel + oxidizer to generate thrust; high thrust, lower efficiency (Isp).
Combustion — Exothermic reaction producing high-pressure gas, expanded through a nozzle for thrust.
Delta-V — Total change in velocity needed for maneuvers; core metric in orbital mechanics.
Electric Propulsion — Uses electrical energy to accelerate propellant; low thrust, very high efficiency.
FCC — U.S. regulator of radio spectrum, including satellite communications licensing.
First/Second Stage — Rocket segments; first lifts off, second carries payload to orbit after separation.
Full-Flow Staged Combustion — Advanced cycle gasifying both fuel and oxidizer before combustion; enables high performance (e.g., Raptor).
Gravity Well — Energy required to escape a planet’s gravity; Earth’s is deep and costly to exit.
Hall Thruster — Electric thruster using magnetic fields to ionize and accelerate propellant for efficient thrust.
Heat Exchanger — Transfers heat between fluids; key in solar thermal propulsion systems.
Launch Vehicle — Rocket carrying payloads to space (e.g., Falcon 9, Starship).
LEO — Low Earth Orbit (200–2,000 km); hub for satellites and near-term space activity.
Oxidizer — Substance enabling combustion (e.g., LOX); required since space lacks oxygen.
Portal Space Systems — Company developing in-space propulsion systems.
SDI — 1983 U.S. missile defense initiative that advanced space and defense technologies.
Solar Sails — Use photon momentum for propulsion; no propellant, extremely low thrust.
Solar Thermal Propulsion — Uses sunlight to heat propellant, offering mid-ground performance.
Specific Impulse (Isp) — Efficiency metric; higher = less propellant used.
Thrust — Force produced by propulsion; determines acceleration.
Tsiolkovsky Rocket Equation — Relates delta-V to Isp and mass ratio; shows exponential propellant requirements.
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