All-Star CalTech Panel Discussion: Moving an Asteroid

Episode Summary

Executive Summary: This Planetary Radio episode spans two major themes: the science and policy of moving asteroids, and a brief planetary science news segment on Eris and journal publication norms. Panelists argue that asteroid deflection is technically feasible with existing or near-term methods, while asteroid retrieval could enable exploration and resource use. The episode also highlights occultation-based measurements showing Eris is about Pluto’s size.

Main Topics: Why move an asteroid closer?: A Caltech/Keck workshop explored whether humans could retrieve an asteroid for study, mining, and as a stepping stone for deeper-space exploration, reframing asteroids as resources rather than just hazards. Planetary defense and deflection methods: Rusty Schweikert and Bill Nye emphasized that Earth can likely be protected using existing technologies such as kinetic impact and gravity tractors, though demonstrations are still needed. Human missions to asteroids: Tom Jones described practical mission concepts for short-duration crewed visits, including radiation exposure limits, surface mobility, and vehicle designs that allow astronauts to work more efficiently. Asteroid composition and resource potential: John Lewis contrasted carbonaceous and metallic asteroids, explaining how both water-rich and metal-rich bodies could support space industry, habitats, and even large-scale populations. Public science communication and the Ingelfinger rule: Emily Lakdawalla discussed how journal rules historically discouraged scientists from discussing unpublished work publicly, though major journals now permit conference-based dissemination. Eris occultation result: Emily Lakdawalla reported that stellar occultations provided evidence that Eris is nearly the same size as Pluto, underscoring the power of indirect measurement for distant objects. Weekly astronomy and trivia segment: Bruce Betts covered skywatching, a space-history note, a random fact about neutron stars, and a trivia question about a Shakespearean moon, adding the show’s customary lighthearted close.

Key Arguments: Asteroids are not only impact threats; they are potentially valuable targets for science, exploration, and resource extraction. Most planetary-defense techniques discussed are already physically available; the main need is demonstration and early detection. A gravity tractor or similar precision method can make fine orbital adjustments after a larger initial deflection. Crewed asteroid missions are plausible for about six months of transit plus short surface operations, but require careful mobility solutions in microgravity. Asteroid materials vary widely: carbonaceous bodies can supply water and volatiles, while metallic asteroids may contain more metal than has ever been mined on Earth. A self-sustaining near-Earth asteroid infrastructure could theoretically support very large populations using solar power and recycled resources. Public discussion of ongoing research is important and should not be stifled by outdated publication rules. Occultation timing can determine the size and shape of distant objects more accurately than direct imaging in many cases.

Data Points: Asteroid discovery rate: 3,000 a month - Lou Friedman noted the rapid increase in known asteroids compared with 1950. Known asteroids in 1950: Less than 50 - Historical comparison used to show how much asteroid knowledge has expanded. Crewed asteroid mission duration: Six months - Tom Jones suggested this is within current free-fall medical experience and potentially tolerable with shielding. Asteroid surface exploration time: Two weeks - Tom Jones described a likely duration for field geology on an asteroid. Carbonaceous asteroid water content: Up to 20% by weight - John Lewis described volatile-rich carbonaceous meteorites. Carbonaceous asteroid organic polymers: Up to 6% by weight - John Lewis on the composition of carbonaceous meteorites. Easily extractable volatiles in carbonaceous meteorites: Up to 40% by weight - John Lewis on resource potential from meteorite material. Population supported by asteroid resources: 10 billion people - John Lewis argued a fully recycling, solar-powered asteroid economy could support this indefinitely. Asteroid belt mass access multiplier: One million times - John Lewis said the asteroid belt offers vastly more material than the near-Earth asteroid swarm. Neutron star size ratio: 60,000 times smaller in diameter than the Sun - Bruce Betts’ random fact segment. Publication date references: October 11 and October 12 entries - Blog posts mentioned during Emily Lakdawalla’s segment. Eris size comparison: Almost precisely the same size as Pluto - Derived from stellar occultation observations.

Pivotal Quotes: "We can now even think about these things and do these things is tremendously exciting because asteroids are turning out to be an incredibly interesting and important subject." — Lou Friedman: Opening remarks at the Caltech panel on moving an asteroid. "We have the capability physically, technically, to protect the Earth from asteroid impacts." — Rusty Schweikert: Argument that planetary defense is feasible with current technology if demonstrated and applied early. "The smallest known metallic asteroids contain more metal than has been mined on Earth in the entire history of the human race." — John Lewis: Explaining the resource potential of metallic asteroids for future space infrastructure.

Implications: The episode frames asteroids as both existential risks and strategic assets. For listeners and industry, the takeaway is that early detection, demonstration missions, and sustained research could enable both planetary defense and a future space-resource economy.