Elon Musk will deliver this year’s most anticipated aerospace speech on Tuesday at the International Astronautical Conference in Mexico. The talk, “Making Humans a Multiplanetary Species,” marks a singular moment for the man who has upended the global launch industry during the last five years and will now finally peel away some of the layers of his grand vision to colonize Mars—and possibly other places in the Solar System.

It was mooted in some aerospace circles that Musk might change the focus of his much-advertised speech at the IAC meeting after the loss of a Falcon 9 rocket earlier this month (the second), the cause of which remains unknown to the public. However, its central theme will remain how to address the challenges of creating a self-sustaining colony on Mars. Indeed, SpaceX recently added a livestream of the talk to its site, complete with a photo of Mars. Clearly, Musk and his company are pressing ahead with their Mars ambitions even as the very difficult, real-world work of assessing an Earth-bound rocket failure continues.

After the speech it seems likely that details about Musk’s much-hyped architecture for Mars exploration—the big spacecraft known variously as the Mars Colonial Transporter or Interplanetary Transport System and rocket, the BFR—will capture the most attention. Everyone wants to see these vehicles, which undoubtedly will ooze magnificence. But at Ars we’ll be watching for something much more prosaic, namely, who pays for all this?

With regard to this question there is one telling line in the description of Musk’s talk: “The technical presentation will focus on potential architectures for sustaining humans on the Red Planet that industry, government and the scientific community can collaborate on in the years ahead.” The notion of industry and government "collaboration" seems a key admission that SpaceX will need substantial financial help to establish a Mars colony.

SpaceX cannot self-fund a Mars colony

In its 14 years of existence, SpaceX has succeeded by providing launch services at a significantly lower cost than its competitors. This has allowed the company to win billions of dollars in NASA contracts, which in turn have provided funds for SpaceX to invest in innovative technologies needed to land on Mars such as supersonic retropropulsion, along with new hardware such as the Raptor rocket engine. However the company does not have bottomless resources—far from it. To date NASA and the US government have been responsible for a significant majority of SpaceX’s revenues, and there is no clear business case for establishment of a Mars colony.

Elon Musk is a billionaire, but his fortunes are strained between supporting SpaceX, the electric automaker Tesla, and the latter's acquisition of Solar City. Although SpaceX has slashed the cost of access to space (a Falcon 9 launch is about one-third the cost of some of its competitors), we do not yet live in a world of cheap spaceflight. To get there, SpaceX must re-fly Falcon 9 boosters often and efficiently enough to make an order of magnitude cut further. And if this occurs, developing all of the Mars hardware will still cost many billions of dollars.

Because Musk cannot self-fund this, and it is unlikely SpaceX will produce billions of dollars in annual profit any time soon, the funds must necessarily come from somewhere else—probably the government. This represents the real challenge of Tuesday’s speech—convincing the “government and scientific community” to collaborate with SpaceX on Mars colonization. Certainly Musk's talk will move the faithful SpaceX devotees, but it remains much more important that it move hearts and open wallets in Washington DC.

Allies in Washington?

Anyone who followed the political struggles in Washington DC over commercial cargo and crew funding during the last decade will recall the hell Congress put private spaceflight companies like SpaceX through. US representatives and senators did not want to give away dollars that had traditionally gone to NASA and its primary contractors, such as Boeing and Lockheed Martin, to firms outside this clique. The battle played out for years, and the commercial crew program only received full funding after it became abundantly clear that delayed spending meant the United States would remain reliant on Russia to launch its astronauts into space. In this hard-fought battle SpaceX had two key allies in Washington: NASA and the President of the United States.

Now, with ambitions that extend far beyond low-Earth orbit, it is not clear which coalitions in Washington DC will stand with SpaceX. Congress certainly won’t. After the static fire incident earlier this month, I spoke and texted with a handful of members of Congress and aides. Their concern wasn’t for the prospects of SpaceX, but rather whether NASA was on the hook for any of the company’s losses. This reinforced the fact that while some members of Congress certainly support SpaceX, many could not care less about the company’s fortunes.

The traditional aerospace industry, too, will likely do what it can to undermine Musk. These companies, accustomed to large, cost-plus contracts prior to the "new space" era of SpaceX and other upstart firms, resent SpaceX for changing the rules of the game, and also for the public adulation the company receives. The traditional powers view themselves as work horses, and denigrate SpaceX as a show pony.

It also seems likely that NASA won’t offer substantial support, either. The space agency is building its own heavy lift rocket, the Space Launch System, and has its own #JourneyToMars. NASA’s administrator, Charles Bolden, has wholeheartedly supported SpaceX and commercial space activities in low-Earth orbit, but has been far less effusive about private businesses venturing into deep space on their own. Earlier this month Bolden flatly stated he was not a “big fan” of private companies building heavy-lift rockets. With its Falcon Heavy and BFR, that is exactly what SpaceX is doing.

Finally, speculating on what the next President might think about SpaceX is somewhat of a parlor game; but again, most of my sources do not envision full-throated support of the company and its Mars architecture from either major-party candidate.

A possible path forward

Washington will also worry about risk. Musk has acknowledged that early colonization missions to Mars will be “dangerous and probably people will die.” This goes against the primary aim of NASA to safely launch and return every astronaut it sends into space. One might argue that any human mission to Mars will carry substantial hazards for astronauts, but NASA will be expected to take every precaution to minimize those risks.

Musk will understand all of this as he takes up a microphone on Tuesday. But he appears set to press ahead anyway, confident in his own plans and ability to sell them. It is risky, but Musk has always been bold. One clued-in private space official, sympathetic to SpaceX, explained it to me as follows: “This is a gutsy move. There is a shaky relationship right now between SpaceX and NASA on a couple of fronts. He’s made a lot of money from NASA over the years, and now he may be about to effectively tell NASA that they’ve had their head up their ass for a long time about how to go to Mars, that this is how we’re going to do it, and you’re going to pay. I don’t know how well that is going to be received.”

The company’s credibility is also in question. SpaceX has suffered two losses of its Falcon 9 rocket in 15 months, and has yet to publicly identify the root cause of the second failure. If the company has yet to master the orbital Falcon 9 rocket, it is prudent to question the viability of future rocket designs that are larger than any booster ever built before.

That is not to say Musk will fail Tuesday. Through his own intelligence and drive, Musk has become the single most important actor in the aerospace industry with his low-cost rockets and forward thinking plans. For much of his life he has been told no, that this or that cannot be done. And then he has gone and tried to do it anyway. Often he has succeeded.

After talking with other sources familiar with SpaceX, NASA, and Washington politics, here is one plausible pathway by which Musk might ultimately reach Mars. Imagine that over the course of the next five years a price tag gets attached to the government’s Journey to Mars program. Using its large, expensive rocket, a handful of Mars landings might cost between $200 billion and $500 billion between now and 2040, which is unaffordable.

Meanwhile, during the next five years Musk might fly his Red Dragons to Mars. He might continue to develop and test the Raptor engines that would power his next-generation rocket. He could make reusable rocketry a reality. He could fly commercial crew missions safely and demonstrate his reliability with US astronauts. He could continue do all of this at a fraction of the cost of similar government programs. If he does this, a commercial pathway to Mars, offered by SpaceX at a cost of $50 billion to $100 billion might have some credibility with a future president and Congress. And if NASA doesn’t buy it, perhaps another foreign government might.

So let’s see what Elon Musk has to say on Tuesday. Let us be dazzled by his architecture, which no doubt will be brilliant. But before Musk ends his speech, we would also like to gain some sense of how any of this is plausible.

Update (1:30p CT, 9/27): You can watch Musk's speech at the livestream below.