Big Rockets and Bigger Dreams: Elon Musk Introduces SpaceX’s Interplanetary Transport System

Arrival
Credit: SpaceX

SpaceX founder Elon Musk took to the stage at the International Astronautical Congress in Guadalajara, Mexico on Tuesday to finally unveil to the public his company’s vision of a Mars transportation architecture capable of ultimately transporting hundreds of thousands of colonists to the Red Planet.

Through the course of the presentation which began with a primer on the overall habitability of the solar system and ended with an open question sequence occasionally bordering on surreal, Musk outlined the basic elements of the two stage space transportation system formerly known as the Mars Colonial Transporter (MCT), and spent a surprising amount of time discussing its broader potential to reach across the entire span of the solar system to the edge of interstellar space. It was this expanded capability which prompted Musk and company to recently change the name to “Interplanetary Transport System.”

But for now, it all begins with Mars, the singular focus of SpaceX since the company was formed in 2002. The backbone of the system is an extremely, but not necessarily improbably large, two stage rocket consisting of a reusable first stage with flight operations taken directly from the current Falcon 9, topped by what could only be described as a true spaceship in the finest tradition of classic science fiction, one which practically screams “Heinlein.” With multiple decks, large open spaces and at least as presently depicted, a gloriously designed multi-paned viewing port, it also looks as though it could have come right from the set design of the current science fiction hit “The Expanse.”

For all that however, the basic concept of operations, orbital refueling in LEO, can also be found in the 2009 Augustine Commission report that was first used to scuttle NASA’s Project Constellation, and then subsequently ignored by Congress in issuing design edicts for the Space Launch System. As outlined and presented in the accompanying video, the methane/oxygen booster would loft an un-fueled passenger ship to LEO, where it would would loiter for several weeks as the booster made a series of repeat missions with a stripped down, tanker version of the same upper stage.

After somewhere between 3 and 5 propellant filling tanker flights, the second stage, now fully loaded with cargo, crew, passengers and propellant, would rocket out of Earth orbit powered by 9 Raptor engines on its way to a rendezvous with Mars. Upon arrival, and using an entry profile honed from data SpaceX hopes to gain from the Red Dragon missions its plans on launching as early as 2018, the ship would enter the Martian atmosphere protected by heat shields on its lower fuselage, slow its velocity using supersonic retro-propulsion, and finally make a tail-first touchdown on extendable landing pads.

At the next orbital window, the ship, now re-fueled using methane and oxygen harvested from the Martian atmosphere, would take off for the return flight to Earth and a landing at its original point of departure. In something of a surprise,  that point would likely be none other than Cape Canaveral’s Launch Pad 39-A, which SpaceX leased from NASA in 2013 and is preparing to press into service at it recovers from the Falcon 9 “anomaly” at SLC-40. SpaceX had previously suggested that its mega rocket would be too big even for a launch pad that hosted the Saturn V and Space Shuttle, but that has now changed, perhaps in part due to the commitment to LEO refueling, an approach which allows for a comparatively smaller, albeit still enormous, booster stage.

While each individual booster stage is indeed truly enormous, standing both taller and wider than the Saturn V, it is the scale of the missions, and the money to pay for them, which is likely to strike many as the most improbable element in the plan. With a focus on developing a self sustaining civilization on Mars numbering some 1 million people, Musk ultimately envisions launching “fleets” of hundreds of ships at a single departure window, a vision which the SpaceX founder acknowledged sounded very much like it came from another science fiction staple, Battlestar Galactica.

It all begins however, with a single booster and spaceship, and in this regard, SpaceX’s plan is already backed by more than vaporware and grand wishes. Just prior to the IAC address, SpaceX released images and video from the first test firing of the Raptor engine on which the booster is based. And in another surprise held back until the presentation itself, Musk provided a series of images of a full-sized, composite liquid oxygen tank which was just completed.

Composite LOX Tank
Credit: SpaceX

Unlike the Falcon 9 , which uses an aluminium-lithium metal tank structure for both first and second stages, the new booster will be of almost completely composite construction, a weigh savings measure which brings a unique set of challenges, particularly when it comes to safely containing super chilled cryogenic fluids. According to Musk, the engineering tank on display has already passed several critical milestones.

One engine and one tank do not a system make however, especially when 50 more engines are required to complete a single rocket, and on this point Musk acknowledged that presently SpaceX is not spending very much on the project, either in terms of cash or engineering effort. That may soon change, as the company hopes to complete its final upgrade of the Falcon 9 relatively quickly, after which it will switch engineering talent and development dollars towards the new booster. After that point, with the Falcon 9 (and Falcon Heavy) as good as it is going to get, and the Crew Dragon safely through its development cycle, Musk plans to be spending some $300 million per year on the project, working towards a possible first flight within the next 10 years.

While some of the funding will come from ongoing profits, and still other portions from outside sources, including hopefully NASA, Musk also indicated that he is prepared to spend the vast bulk of his personal fortune on the project. In fact one of the most powerful and well received moments of the presentation came when he noted that funding the new system is the only reason he is motivated to accumulate significant wealth in the first place.

But what about the hundreds of thousands of individual colonists upon whom ultimate success depends?

With the current ticket price to Mars cheerfully cited as either $10 billion per person, or more realistically, unobtainable at any price, a dramatic reduction is clearly necessary. How much? According to SpaceX, 5 million percent, a figure which would bring it down to something on the order of $200,000 per person. This is a figure Musk has cited in the past, drawing an equivalency to the median cost of a home in the U.S. At that rate, which after all happens to be what Virgin Galactic used to be charging for a few moments of suborbital flight before it raised prices, some small but measurable percentage of the global population would be willing to go, particularly since the need to recover each spaceship for reuse would hold open the possibility of going back to Earth if living on Mars turned out to be a bit of disappointment.

Coming anywhere close to that figure demands nearly 100% re-use of all components, combined with long life spans to allow costs to be divided over the course of multiple missions. For the spaceship itself, which can only fly every 26 months as the Earth/Mars orbital window opens up, this presents a challenge, but for the booster, the task is somewhat more manageable, with dozens, if not hundreds of flight opportunities coming in the way of propellant transfer flights as well as non-Mars missions. Somewhat surprisingly, Musk speculated that point to point Earth transportation flights could become a possibility. So too could launches to anywhere else in the solar system, where the booster’s enormous lift capacity and refillable spacecraft/second stage could one day be landing anywhere in the solar system with a solid or even liquid surface.

As SpaceX sees it, only the Gas Giants and the hell fire and brimstone surface of  Venus are out of reach, and in the case of the former, there are many, many moons to beginning with Europa in the Jovian system, and Enceladus and Titan at Saturn.

Where it goes from here, only time will tell, but keep this one fact in mind. In 2011, a year in which SpaceX did not launch a single rocket, Elon Musk introduced both the Falcon Heavy and Falcon Reusable programs at separate press events. Five years later, Falcon Heavy has yet to fly, but at the same time, SpaceX has already made the art of recovering orbital boosters appear almost routine.

The complete replay is below.