How to Build a Starship: The 2019 Starship Congress

Episode Summary

Executive Summary: This episode of Planetary Radio covers the Planetary Report’s Venus and planetary defense features before devoting most of its runtime to the 2019 Starship Congress, where presenters explored practical steps toward interstellar flight: gas-gun launchers, lunar elevators, biotechnological survival in space, speculative thermodynamics research, and science-fiction-informed future planning. David Brin closes by arguing that “bending metal” is really about building the industrial and intellectual infrastructure for space civilization.

Main Topics: Planetary Report highlights: Venus, planetary defense, and why we explore: Emily Lakdawalla discusses the latest Planetary Report issue, including a Venus science article based on Venus Express and Akatsuki, an update on planetary defense and city-killer asteroids, and the magazine’s ‘Why I Explore’ feature inviting members to explain why space exploration matters. Green Launch and high-speed gas-gun launch systems: John Hunter describes Green Launch’s hydrogen gas-gun technology as a low-emission first stage concept aimed at reaching orbital-class speeds and lowering access-to-space costs for small payloads. Starship Congress and the ‘bending metal’ philosophy: Andreas Diolosa frames Icarus Interstellar’s Starship Congress as a recurring meeting to move interstellar concepts from speculation toward engineering, emphasizing that building a starship also means building knowledge, teams, and institutional momentum. Biological and ecological challenges of interstellar travel: Christoph Latz argues that life-support, radiation, recycling, food production, and genetic diversity may be as difficult as propulsion for long-duration interstellar travel, while using extremophiles to illustrate life’s resilience. Second-law skepticism and exotic energy ideas: Daniel Sheehan presents experimental work suggesting possible violations or loopholes in the second law of thermodynamics, arguing that efficient heat-to-work conversion could radically reduce spacecraft energy burdens. Lunar space elevator and the shift toward cislunar infrastructure: Michael Lane explains why a lunar elevator is much more feasible than an Earth elevator, due to weaker gravity and no atmosphere, and positions the Moon as a hub for space industry and logistics. David Brin on space civilization, asteroids, and science-fiction thinking: Brin argues that permanent space presence will come from infrastructure, not one-off flags-and-footprints missions, and champions asteroid resources, private-sector experimentation, and science fiction as a tool for planning unforeseen events.

Key Arguments: Venus remains a crucial but underappreciated target because its layered atmosphere teaches us about planetary climate and potential future missions, including balloons and cloud-level exploration. Planetary defense has progressed from identifying civilization-ending threats to focusing on city-killer asteroids, especially objects approaching from near the Sun that require dedicated observatories like NEO Surveyor/NEOCam-type concepts. Interstellar flight research should prioritize enabling technologies first; systems that do not reach the stars directly can still lower the cost and risk of access to orbit and cislunar space. A starship is not only a vehicle but a civilizational project; even partial progress creates educational, technological, and cultural benefits. Biology may be the limiting factor for starships: radiation shielding, closed-loop recycling, food production, and preserving a viable gene pool could dominate mission design. Alternative thermodynamic approaches, if real, could provide near-limitless reusable energy from ambient heat, transforming spacecraft endurance and propulsion economics. The Moon is a better near-term infrastructure target than Mars for building a broader space economy because it can supply material resources while Earth supplies labor, knowledge, and markets. Science fiction and speculative thinking are valuable because they train institutions to respond to unusual discoveries and “what if” scenarios before they happen.

Data Points: Venus missions discussed: 2 - Emily Lakdawalla highlights Venus Express and Akatsuki as the basis for the Venus article in The Planetary Report. Years between Starship Congress events: every 2 years - Andreas Diolosa says Starship Congress has been held biennially since 2013. Green Launch test speed: Mach 5 - John Hunter reports the most recent 20-second test reached Mach 5. Projected Green Launch goal: Mach 8 - Hunter says the team hopes to get to Mach 8 in future tests. Launcher output speed: 6 kilometers per second - Hunter describes the system as delivering about 6 km/s, approaching orbital-class velocities. Orbital velocity: 7.6 km/s - Hunter cites this as the typical orbital velocity needed to stay in orbit. Velocity to reach orbit: about 9 km/s - Hunter notes total launch-to-orbit velocity is typically around 9 km/s. Lunar elevator estimated cost: about $800 million - Michael Lane estimates the lunar elevator could be built for under a billion dollars. Original Earth elevator estimate: $15–20 billion - Lane contrasts the lunar elevator with earlier Earth elevator estimates. Biological time frame for generational starships: 100–500 years - Christoph Latz and David Brin both discuss multigenerational interstellar travel as a centuries-long challenge. Minimum population for gene pool stability: several thousand people - Latz says a generational starship would likely need several thousand humans to maintain diversity. Autoclave sterilization temperature: 121°C - Latz references bacteria strain 121 surviving conditions used in autoclaves. Age of Venus orbiters referenced in trivia: last three orbiters - Bruce Betts’ trivia question asks listeners to name the last three Venus orbiters. Milky Way satellite galaxies mentioned: at least 54 - Bruce Betts notes there are at least 54 known satellite galaxies orbiting the Milky Way.

Pivotal Quotes: "“We call it a starship is both a term of art as much as it is a factual object.”" — Andreas Diolosa: Explaining that interstellar work is as much about process, education, and capability-building as it is about building a literal spacecraft. "“If you hate CO2, you'll love our system because we don't emit any CO2.”" — John Hunter: Describing Green Launch’s hydrogen gas-gun concept as a low-emission launch technology. "“The effort towards achieving a starship is the education, the know-how, the cultural changes that we would go through.”" — Andreas Diolosa: Arguing that the value of interstellar research includes broader civilizational benefits beyond the hardware itself.

Implications: The episode frames near-term space progress as infrastructure-building: cheaper launch, lunar logistics, robust life support, and advanced science all matter as much as starships themselves. The broader lesson is that speculative ideas can become practical programs when communities, industry, and institutions keep iterating.