Domes on Earth and Mars

Florence’s dome was the largest built in a thousand years, but the designers knew it could not be completed on their current budget using existing construction techniques. Even if they did scrounge up the funds, the probability of failure would be frighteningly high (like >50%). Luckily, Brunelleschi invented a new construction technique and today the Cathedral and dome stand as symbols of the Renaissance. It took 140 years, tons of money, and the birth of a genius to do it. What would it take to build a dome on Mars?

The first thing you need is motivation. Florence was motivated by competition with neighboring Pisa and Siena for regional dominance. I would argue that the case for humans on Mars is similarly motivated by geopolitical interests, not survival of the species or even science. We go to Mars to extend our ideological influence, be it as an independent nation or a coalition of nations which share common values. Some values that probably make the top ten include freedom of thought and expression, the importance of science and technology, the power of collaboration and the reward of excellence.

Is there a business case for sending humans to Mars? Is there a reason to have humans do science work on Mars instead of robots? If there is, please email me. For science purposes, I would send several robots and relay satellites for a fraction of the cost of a human mission. I think the reason to send humans to Mars is largely ideological or political.

Once you find your motivation, the second thing you need is a workable design. Clearly, you don’t need the full design up front, but you do need to be able to begin work immediately. And for a long-term project, this design needs to be set in stone.

Research reveals that a number of redesigns occurred during the construction of the Cathedral. This happened so frequently that the _capomaestri_ (building committee) had to literally take an oath to stop redesigning it in 1368. We are seeing similar problems with the Mars proposals, and Congress has begun explicitly writing some of NASA’s mission designs into US law so that they cannot be modified by a new chief executive or administrator. For instance, last December’s omnibus specifies the configuration (lander) and launch method (SLS EUS) of a new Europa robotic mission. Despite my hesitancy to put engineering in the hands of politicians, this wielding of legislative power could help prevent NASA from losing time to design thrash.

In addition to consistency, the design must be readily actionable. Florence was able to build everything in the Cathedral except for the dome using existing technology. It was just that last 10% they were missing. Does the Mars program have a strong foundation of existing technology to get us 90% of the way there? Unfortunately, I think this is the weakest part of the Mars conversation. We haven’t sent a human to the Moon in half a century, or a lab rat to Mars ever. We don’t have the existing technology to even pretend that sending humans to Mars is a good idea right now, so where do we start?

The Cathedral as it stands today was built on the grounds of an older church, which itself was built on the grounds of an even older church. Builders often progressively enlarge churches by extending the walls outward to create a new space which contains the existing space. Similarly, we could extend into space by progressing outward from the space station to a Moon-based station, to a station on a Martian moon, to a station on the surface of Mars. That’s not exactly NASA’s plan, though.

I think NASA is on the right track. We have motivation, we have designs that are starting to solidify in law while still allowing room for innovation in the later stages, and we are building a technological foundation on real missions rather than abstract capabilities. If we let this system run, I bet we’ll have domes on Mars in less than the 140 years it took to build the Cathedral and dome in Florence.

If we wanted to accelerate that timeline, I might try to emphasize three points to help lay the foundation for a human Mars mission as early as possible.

  1. Begin robotic experimentation with in-situ resource utilization to produce fuel, water, and protective structures on the Moon and Mars.
  2. Work with other agencies to put structures on the south pole of the Moon, not “near” the Moon as the current NASA plan states.
  3. Focus on using the space station now to improve technologies needed for Earth-independent missions, like water reclamation and 3D printing spare parts. Don’t wait until the 2020's.

Note that I am not a space policy expert and that I don’t have more than an internship’s worth of experience working on technology for Mars missions. I would certainly like to learn more and I’ll continue writing on the topic, so subscribe to my newsletter if you would like to stay up to date.

More on this topic

The geodesic dome pictured in this post is from an article about the Hawaii Space Exploration Analog and Simulation (

Scott Pace has a lot to say about the geopolitical motivations for space exploration. You may find his 2015 senate testimony interesting. (pdf)

You can read about the design (and redesigns) of the Florence Cathedral in Franklin Toker’s article, “Florence Cathedral: The Design Stage.” (pdf)

If you like staying up-to-date on NASA’s plans for human exploration, there are some recent presentations to the advisory committee here. Alternatively, ISECG provides an exploration roadmap for the global space community in the near term. (pdf)

If you like alternative Mars exploration architectures, you can read the Humans Orbiting Mars report by the Planetary Society (website), and watch a film about the Mars Direct strategy by the Mars Society (website). Note that those two societies are not related.

This post is actually from my space blog,

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