Participants

· Robert Zubrin—Founder of the Mars Society and Pioneer Energy

· Nick Beckstead—Research Fellow, Future of Humanity Institute at Oxford University; Board of Trustees, Centre for Effective Altruism

Summary

Purpose of the conversation: I organized this call to learn about the feasibility of space colonization in the very long run.

Why this person: Robert Zubrin is the founder of the Mars Society—a group advocating for colonizing Mars. He is also the author of two books on space colonization: The Case for Mars and Entering Space: Creating a Spacefaring Civilization (with a few chapters on interstellar colonization). Anders Sandberg recommended that I speak more with him to learn about this issue.

Dr. Zubrin believes there are no insurmountable obstacles to colonizing planets in this solar system or other solar systems. He is aware of no compelling technical arguments to the contrary, thought the potential obstacles discussed could be overcome (energy requirements, high costs, inhospitable atmospheres, space dust, radiation), and couldn’t imagine learning anything remotely plausible which would change his mind. There is abstract and ideological resistance to the feasibility of space colonization in some environmental quarters, but these skeptics do not meaningfully engage with technical arguments, in his view.

What do you believe about the long run feasibility of space colonization, especially interstellar colonization?

In the long run, he believes that humans will colonize space, both inside and outside of our solar system. Human beings have a basic drive to go places they’ve never gone before and do what they’ve never done before.

Within our solar system, SpaceX might succeed in the relatively short term. Whether it takes 10 to 50 years to colonize our solar system or more than 100 years depends on many contingent events that are hard to predict. But, in the end, Dr. Zubrin believes we will do it.

If you look at the amount of energy required for interstellar missions and you look at the rate of increase of our deployment of energy over the last few hundred years, and you assume that this rate continues for the next 200 years, we’ll have enough energy for interstellar missions. Dr. Zubrin believes that we’ll eventually have the necessary amount of energy. He said that there are identifiable propulsion technologies which would work—given the laws of physics as they are currently known—and these could get us up to a few percent of the speed of light, allowing us to get to the nearest stars in decades rather than millennia.

Who are the experts on the long-term feasibility of space colonization (especially interstellar colonization)?

Dr. Zubrin stressed that there are no “experts” on space colonization, though some people have more expertise than others.

People to talk to:

· Elon Musk –CEO and CTO of SpaceX

· Christopher McKay—Planetary scientist at NASA Ames Research Center

Who are the most credible skeptics of the feasibility of space colonization?

The main skeptics of the feasibility of space colonization that Dr. Zubrin is aware of are environmentally-oriented people influenced by publications like Limits to Growth. However, Dr. Zubrin puts little weight on these arguments. Moreover, these skeptics do not engage with technical arguments about the capabilities of engineered systems.

Dr. Zubrin is aware of no remotely compelling technical arguments against the in-principle feasibility of space colonization. I told him that the most compelling skeptical case I had found was due to Charles Stross, and he thought it was unlikely that I was missing any compelling technical arguments against the in-principle feasibility of space colonization.

Why might space colonization (especially interstellar colonization) be impossible?

In Dr. Zubrin’s view, there are no insurmountable obstacles to space colonization, either inside or outside of our solar system. Some of the major obstacles now are the high cost of space colonization and planets not having hospitable atmospheres. He believes that the former obstacle can be overcome as costs go down with technological advances, and the latter can be overcome through terraforming (e.g. in the case of Mars) or by finding more hospitable planets (in the case of interstellar colonization).

I mentioned a couple of the potential obstacles to interstellar colonization that came up in my interview with Anders Sandberg: space dust (which might damage vessels moving close to the speed of light) and radiation. Dr. Zubrin didn’t think space dust was a serious concern, and argued that damage from radiation could clearly be prevented with adequate shielding. He pointed to the fact that we’ve had people working close to nuclear reactors on nuclear submarines for over 50 years without major problems.

I asked Dr. Zubrin whether he could imagine anything we could learn—consistent with everything we currently know about physics—that would mean space colonization would be impossible. He said he could not think of anything remotely plausible fitting the description. It’s just a question of how fast we can get there.

When thinking about interstellar colonization in the very long run, do you imagine humans travelling long distances in spaceships, or something more like von Neumann probes?

Dr. Zubrin tends to imagine humans travelling long distances in spaceships, though self-replicating robots that prepare the way would also be a possibility. He believes that, in the long run, flesh-and-blood humans will live in other solar systems.

Questions sent to Zubrin prior to our meeting

1. What do you believe about the long run feasibility of space colonization, especially interstellar colonization?

2. Who are the experts on the long-term feasibility of space colonization (especially interstellar colonization)?

3. What is the range of opinion among these experts? Who are the most credible people arguing for in-principle feasibility? Who are the most credible skeptics?

4. Why might space colonization (especially interstellar colonization) be impossible? (Alternate framing: Imagine you learned that space colonization wasn’t technologically possible for us, even in principle. In your mind, what are the most plausible reasons that could be true?)

5. When thinking about interstellar colonization in the very long run, do you imagine humans travelling long distances in spaceships, or something more like von Neumann probes?