Today Elon Musk gave a speech at the International Astronautical Congress in Guadalajara, Mexico. The speech laid out SpaceX’s proposed architecture for building what he presently calls his interplanetary transport system. The image on the right is one of his talk slides, showing the basic concept, which is built around using the company’s new Raptor engine — still under development — which only got its first test firing this past week.
The plan is ambitious and visionary, which from Musk is not surprising. It is also aimed to be as practical and as cost effective as possible, which also is not surprising coming from Musk. The rocket itself will be larger than both the Saturn 5 and SLS, but not significantly more. Compared to those government rockets however it will be far cheaper and faster to build, though Musk’s hope that they will be launching their first test flights in four years is almost certainly too optimistic. The concept is to use what they have learned with the Falcon 9 to build a bigger rocket with a reusable first stage that launches a large second stage that is either the spaceship taking people to Mars or a giant tanker for refueling that spaceship.
In one of Musk’s early slides he noted something that I have been arguing for decades. “Speading the required lift capacity across multiple launches substantially reduces development costs and compresses schedule.” Though he is still proposing a heavy-lift rocket, he is also following in the footsteps of Wernher Von Braun by proposing that any Mars mission will require some assembly in orbit.
The plan is also aimed at making space travel as affordable as possible. Musk structured the design in as many ways as possible to make it as efficient and as inexpensive as possible. It still won’t be cheap, at about $140K per ton, but at that price it will be affordable to a lot of people. He also mentioned that it include free passage back to Earth.
I doubt we will see this system built as outlined today in the time span predicted by Musk. At the same time, I would not be surprised if we do see some variation of it, and see it built within the near future. In 2011 Musk proposed recovering his Falcon 9 first stages by landing them vertically. The idea seems radical. He got it done in four years. There is every reason to believe he will make this Mars proposal happen as well.