5 Things We Learned from Elon Musk’s Reddit AMA
published during a waning crescent moon.


Credit: SpaceX

Last month, Elon Musk, head of private spaceflight company SpaceX, unveiled blueprints for Mars amid gasps from the audience. The behemoth architecture was certainly worth the sharp inhalation: The simulation of the interplanetary mission not only looked beautiful, it revealed a gigantic rocket that dwarfs its humans to the real-life equivalent of pixels.

As a supplement to his International Astronautical Congress talk that took place in Guadalajara, Mexico, Musk took to Reddit’s SpaceX page to answer Redditors’ questions about becoming a spacefaring civilian. Here are some highlights from the Ask Me Anything (AMA) session:


Credit: SpaceX

They already have a plan to keep missions nourished with fuel.

Musk laid out the basic procedures for that one pesky caveat about traveling to Mars, which is that the planet happens to be pretty far away. Loosely: The Dragon, a free-flying spacecraft that can deliver both cargo and people, will scout where to land to ensure it can do so without adding a crater. The first ever colony ship, the Heart of Gold — a Hitchhiker’s Guide to the Galaxy nod — will make its way to the planet loaded only with equipment to build a propellant plant to boost the reusability of the ships (and reduce refueling costs). After a crewed mission builds a rudimentary base and completes the plant, SpaceX will try and double the number of 26-month flights between Earth and Mars “until the city can grow itself.”

Elon Musk’s Reddit AMA

Credit: Carlos Cuz / Creative Commons

Mars could have a city of glass domes.

When picturing what the Martian landscape would look like with habitable spaces, Musk envisions geodesic domes, which have triangular elements to distribute stress in the structure — much like the giant Epcot’s Spaceship Earth, but a dome instead of a sphere. Connecting the domes would be tunnels, which can span large amounts of pressurized space, leaving the domes for green living.


Credit: SpaceX

42 is a very important number.

Not only is it the number of engines of the Interplanetary Transport System (ITS) booster, it’s another Hitchhiker’s Guide reference. “It had to be 42 for important scientific and fictional reasons!” Musk insists. But the term ITS might not stick around for long, he says, because it’s just not working for him. Some names he uses instead? BFR and BFS, which stand for Big Fucking Rocket and Big Fucking Spaceship.

Elon Musk’s Reddit AMA

Credit: SpaceX

This fuel tank prototype is shockingly huge — and will be tested in the ocean soon.

For people who know their stuff, this fuel tank was the real headline, Musk said. The tank itself is made of a carbon fiber composite, a sturdy but flexible material that’s also very low in density. Carbon fiber by itself is hard to mold, so it’s usually mixed with a pastier material like resin, according to Forbes. It can withstand “insane” pressures and intensely hot and temperatures, Musk explains, like cryogenic propellant and hot oxygen. That makes it perfect for space travel as well as other technology susceptible to stress, like the domes’ glass pane frames. Musk also teased that early tests have been promising — and that they’re likely to take the tank up to two-thirds of its burst pressure on an ocean barge in the next few weeks.


Credit: SpaceX

But SpaceX hasn’t quite mastered anything yet.

Except maybe starting engines, Musk said. Is he showing humility, or shrouding more reveals in secrecy? It’s up to you to decide.

If you’re interested in even more details, including the deeply technological, you can visit the AMA here.