Elon Musk to test massive fuel tank for Mars colonization

The CEO of the commercial space company answers a handful of questions in a Reddit "Ask Me Anything" session Sunday, focusing on the company's audacious plan to colonize Mars.

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This development fuel tank will be tested at sea to see how it might fare on a trip to Mars.


Elon Musk is moving forward with his plan to build a metropolis on Mars in the coming decades. The SpaceX CEO and founder followed up his magnum opus presentation from last month by taking questions in a Reddit "Ask Me Anything" session Sunday during which he revealed plans to test the Interplanetary Transport System's (ITS) huge fuel tank at sea.

"Early tests are promising," Musk wrote in response to a question about the gigantic development tank that SpaceX has already built, which was revealed during the presentation in September. "Will take it up to 2/3 of burst pressure on an ocean barge in the coming weeks."

The tank Musk is referring to sort of a proof of concept for one of the refillable fuel tanks that would be used to fly a spaceship carrying up to 100 humans back and forth between Earth and Mars. This particular tank would carry liquid oxygen, one of two fuels (the other is methane) that SpaceX says could be made on Mars and used to power the ITS.

"The flight tank will actually be slightly longer than the development tank shown, but the same diameter," Musk explained. "In theory, it should hold cryogenic propellant without leaking and without a sealing linker."

We've also seen SpaceX test the Raptor rocket engines that it says will be used to get the ITS into space from Earth.

Musk also shared a few more details about how he hopes to set up shop on the Red Planet in the AMA:

"We are still far from figuring this out in detail, but the current plan is:

  1. Send Dragon scouting missions, initially just to make sure we know how to land without adding a crater and then to figure out the best way to get water for the CH4/O2 Sabatier Reaction.
  2. Heart of Gold spaceship flies to Mars loaded only with equipment to build the propellant plant.
  3. First crewed mission with equipment to build rudimentary base and complete the propellant plant.
  4. Try to double the number of flights with each Earth-Mars orbital rendezvous, which is every 26 months, until the city can grow by itself."

A look at Elon Musk's plan to move us to Mars (pictures)

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He added that he envisions sending "a lot of miner/tunneling droids" in the beginning that could be used to create underground industrial areas while above-ground geodesic domes made from glass and carbon fiber frames can be used for "green living space."

Presumably some other technology will need to be employed or invented to shield that living space from the heavy dose of radiation colonists are likely to receive above ground. Musk himself has said he thinks the threat of radiation is overblown but some space health experts disagree.

Musk said the first crewed mission, which would be via the ITS using the aforementioned fuel tank, would probably be heavily loaded with cargo and "about a dozen people, as the goal will be to build out and troubleshoot the propellant plant and Mars Base Alpha power system."

Watch this: The CraveCast crew debates joining Elon Musk's million on Mars, Ep. 28

That's also the first time we've heard Musk use a name for his dream settlement.

But before Musk and SpaceX detail just what Mars Base Alpha will look like, the CEO says we'll likely get a glance of the "habitation section" of the ITS. In other words, what the living quarters of the spaceship to Mars would look like. This is a bigger deal than on most flights, since passengers will spend several months making the trip from Mars to Earth.

Musk said "actual live mockups" of the living quarters will be released "maybe in a year or two."