Yes, Elon Musk still absolutely wants to go to Mars. But in a speech delivered Friday in Adelaide, Australia, the founder of SpaceX opened the door to sending humans to the Moon first. "It’s 2017, we should have a lunar base by now," he said, speaking just a couple of years shy of the 50th anniversary of the Apollo landings. "What the hell is going on?"

This was just a single line in his talk, which was filled with exhilarating moments but also—critically—some welcome doses of reality. A year ago, when Musk unveiled his Mars rocket at the same annual meeting of the International Astronautical Congress, the presentation felt much more like science fiction than something that might become a reality. It lacked any real semblance of a plan to pay for the rocket.

This year, Musk's talk still sparkled with almost unimaginable technology. But it was leavened with enough tidbits of plausibility to think he just might maybe-sorta pull this off one day. After all, it was only nine years ago that the company made its first successful launch, a tiny Falcon 1 rocket that took flight after three consecutive failures. Now, SpaceX is proving out the technology that underlies reusable rockets, and it stands at the precipice of capturing at least a third of the global launch market.

The spacecraft

During a 40-minute talk in a theater, Musk spent considerable time sharing technical details about the "BFR" system, which includes a reusable rocket with 31 Raptor engines and a staggeringly tall 48-meter spacecraft. It seems that SpaceX hasn't quite yet come up with an acceptable name for the system. Last year, it was the Interplanetary Transport System, but now Musk has regressed to using the original, cheeky "code name" BFR, in which the B stands for big, the R stands for rocket, and the F stands for fun. (Not really).

The rocket, which would stand 106 meters tall, would have the capability to lift 150 tons to low Earth orbit under its fully reusable mode. It would have nearly double that in an expendable capacity, but Musk envisions flying the BFR for mostly reusable flights. Certainly, a rocket with 31 engines seems unwieldy, but later this year, or in early 2018, SpaceX will likely fly its Falcon Heavy rocket. It will be powered by 27 Merlin engines, which although smaller and less powerful, will nonetheless provide a test case for managing so many engines in flight.

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Perhaps the most interesting aspect of Friday's talk was Musk's elaboration on the spacecraft, which has a diameter of 9 meters and encompasses six engines, propellant tanks, and a large payload area that could carry many satellites into space or house 100 people on a journey to Mars. The spacecraft has a pressurized volume of 825 cubic meters, Musk said, which is only about 100 meters less than the entire interior volume of the International Space Station.

For crew comfort, the interior of the spacecraft could have up to 40 cabins, a galley, and a shelter for passengers to climb into during a solar storm. Notably, the spacecraft would also have the capability to dock with another one in Earth orbit. Using several of these refueling maneuvers, a spacecraft might depart Earth orbit with full fuel tanks and thereby deliver as much as 150 tons to the surface of Mars.

The destinations

SpaceX's raison d'être has always been going to Mars. But during his talk Friday, Musk raised the prospect of using the BFR system to build "Moon Base Alpha," noting that the propulsive landing technologies being perfected by the Falcon 9 rocket could be used to land on the airless Moon. (More, later, on why he likely did this.) At the end of his speech, Musk also discussed point-to-point transport on Earth, with the BFR systems taking passengers from New York City to Shanghai in 39 minutes. "If we’re building this thing to go to the Moon and Mars, then why not go to other places on Earth as well?" he asked.

Still, SpaceX's long-term focus remains on Mars. After showing a slide that indicated SpaceX has a goal of sending two BFR spacecraft to Mars in 2022, Musk quipped, "That’s not a typo, although it is aspirational." Musk said SpaceX could begin production of the first BFR spacecraft in the second quarter of 2018. "I feel fairly confident that we can complete the ship and be ready for a launch in about five years," he said. "Five years seems like a long time to me."

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The two spacecraft, carrying only cargo, would be used to confirm water resources on Mars and identify hazards for future missions. They would also place power, mining, and life support infrastructure for future flights. In 2024, two crew ships and two cargo ships would follow, setting up a production plant to make fuel from the thin Martian atmosphere and begin building a base for future residents. "I think it’s quite a beautiful picture," he said.

The technologies

But is this beautiful picture at all realistic? As ever, this remains the key question for SpaceX, Elon Musk, and their dreams of sending humans to Mars.

At the outset of his presentation, Musk listed some of the technologies needed to make the BFR system a reality, citing the progress SpaceX has made toward their maturation. For example, the Raptor engines that will power the rocket have undergone 1,200 seconds of firing over the course of 42 main engine tests. A single engine has fired for as long as 100 seconds. The company has also begun testing a large, 12-meter carbon fiber fuel tank that is essential for keeping the mass of the BFR low to accommodate more usable mass during launch.

Landing on the Moon, Mars, or elsewhere will also require propulsive landing, which SpaceX has demonstrated with 16 consecutive, successful landings of its Falcon 9 rocket first stage on Earth. With the Falcon 9 rocket, SpaceX is also taking steps toward higher launch rates, which would be needed if SpaceX is to ever really launch a serious Mars program. In 2017, the company is on pace for 20 launches, and it plans to make 30 next year, Musk said.

With the company's forthcoming crewed Dragon spacecraft—which NASA has paid for through the commercial crew program—SpaceX has been able to develop a fully automated docking and rendezvous system that is essential for orbital refueling. With Dragon, too, SpaceX has been able to test heat shields needed for a return from the Moon or Mars, Musk said.

Paying for it

It certainly remains an open question as to whether SpaceX can pull off the technological mastery behind the BFR system, but it at least has a start. That raises the question of whether the California company has the funding to pay for it.

Musk seems to think he has solved that problem, as he intends to consolidate the Falcon 9 and Falcon Heavy rockets, and the Dragon spacecraft, into a single reusable architecture—the BFR system that can meet the needs of all its existing clients, and many more. "This way, we will be able to apply all of our resources to one system," he said.

That is, if SpaceX can use the BFR to launch commercial satellites and national security payloads, as well as delivering cargo and crew to the International Space Station, it will have enough of a funding wedge to design, develop, and fly the BFR system. This seems optimistic (a shocker with SpaceX, we know). But it does not seem entirely out of the realm of possibility if SpaceX can leverage NASA and military development contracts to build the BFR system.

The politics

Musk's talk on Friday comes less than a week before Vice President Mike Pence convenes the first meeting of the National Space Council in Virginia. Although the timing may be coincidental—Musk's talk has been scheduled for months—it seemed clear that Musk was attempting to speak to the Trump administration and its plans for space. Both the executive secretary of the space council, Scott Pace, and the nominee to become NASA administrator, Jim Bridenstine, want to see a return to the Moon before NASA ventures onward to Mars.

The remarks about Moon Base Alpha seemed calculated to catch their attention. NASA is already spending $3.5 billion a year on the Space Launch System rocket and Orion spacecraft, which remain at least two years away from taking flight. And these vehicles won't have the capability to land on the Moon or Mars; rather, they're going to build a small station in orbit around the Moon in the mid- to late-2020s. Musk has held out the prospect of much, much more, beginning with going directly to the lunar surface.

Theoretically, the BFR system has two critical advantages over NASA's SLS rocket: cost and capacity. If SpaceX can make the BFR system mostly reusable, it will severely undercut the estimated $2 billion to $3 billion cost of an SLS launch. And with orbital refueling, a single BFR spacecraft could deliver 150 tons to the surface of Mars, compared to 20 to 40 tons with the SLS rocket. It is also notable that the nearly 9m wide fairing of the BFR rocket is comparable to the large 8.4m fairing of the SLS rocket.

But will the Trump administration listen? Phil Larson, a veteran of SpaceX who is now an assistant dean at the University of Colorado Boulder’s College of Engineering and Applied Science, said he isn't sure. "With the upcoming first meeting of the council chaired by Vice President Pence, it will be interesting to watch if the policies being discussed will accelerate or stagnate ambitious private sector ideas like this that could lead to new jobs and industries of the future."

Even so, NASA doesn't offer the only pot of money. Later this year, the US Air Force is expected to begin soliciting bids for up to three prototypes of next-generation launch vehicles. Potentially, billions of dollars might be available over the next decade to provide the military with modern, US-made rockets to launch its assets into space. The timing of these awards could be fortuitous for Musk, SpaceX, and the BFR.

Certainly, even the most ardent fans of Musk and his ambitions in the Adelaide audience cannot really believe the BFR will land humans on Mars seven years from now. We don't. But on Friday, Musk took a step forward by beginning to ground his Mars plans in the real world. It seems foolhardy to entirely count him out.