Insight | Humans to Mars soon, robots first, or floating cities instead?
Martin Rees weighs robots against human pioneers on Mars, Jim Gates doubts a Mars landing by 2030, Ariel Ekblaw argues floating cities may beat Mars, Adam Frank discusses Mars and space habitats, and Brian Greene talks about the engineering of exploration. Comparing them separates the timelines and the reasons for sending people from the enthusiasm.
Five conversations on the Lex Fridman Podcast give five different answers to when people will live on Mars and why anyone should go. Three of the guests agree on one thing: Mars is not a near-term escape from Earth's problems.
Martin Rees, an emeritus professor of cosmology and astrophysics at Cambridge, argues that robots should do nearly all the useful work. Machines need no food for the roughly 200-day journey and no ride home, and future AI will be able to do geology, so he sees the practical case for humans as very weak. Human spaceflight, in his view, is an adventure best left to billionaires and adventurers, not to NASA or public funding. He still hopes for a small, uncomfortable community on Mars by 2100, and he expects those pioneers to modify themselves with genetic and cyborg techniques. He calls mass emigration a dangerous illusion, since fixing the climate here is easier than terraforming Mars: "there's no planet B."
- James Gates Jr. is blunt about the near term: "I am extraordinarily convinced we will not put a human on Mars by 2030." Apollo took about 5% of the country's economic output for ten years to go 250,000 miles; Mars is about 100 times farther, and today's spending is about a tenth of that. Radiation worries him most, since two years outside Earth's magnetic shield probably means cancer. He guesses at roughly 2090 to 2120, and imagines a mind exported to hardware making the trip instead.
Ariel Ekblaw of MIT thinks small, supplied outposts like Antarctica's McMurdo station are possible in the 2030s. She names radiation and mental health as the big challenges and expects long missions to need spinning habitats. Her hot take is that larger populations in space will live in floating cities built from self-assembling tiles, which she has tested on the International Space Station. She sees space technology as a way to keep Earth livable.
Adam Frank expects millions, maybe billions, of people in the solar system within a few hundred years, mostly in habitats such as a small asteroid wrapped in a spinning nanofiber bag rather than on Mars. A self-sufficient Mars colony, he says, is two to three centuries away, too late to be a backup for threats that are pressing now.
Brian Greene calls colonization fundamentally an engineering problem that will later make physics problems relevant, and thinks a child could be born on Mars within Fridman's lifetime. Fridman pushes back on Rees and Frank, arguing that a small backup and the inspiration it gives are worth pursuing.
They disagree on dates partly because they measure different things: a landing, a supplied outpost or a colony that sustains itself. They also split on who should pay, whether today's reusable rockets are a real breakthrough, and whether people will live on Mars or in orbiting habitats.
What to do with it: when you hear a Mars date, ask whether it means a landing, an outpost or a colony. Test plans against the Apollo yardstick, watch progress on radiation and crew health rather than only on rockets, follow robotic missions as the main path for near-term exploration, and keep solving Earth's problems here first.
