For the past few years, the serial entrepreneur and social-media sensation has been talking up his plans to build a massive rocket capable of taking passengers to the moon, Mars, and even deeper in space. He's also talked of building a Martian city one million humans strong.
As soon as this week, SpaceX could begin low-altitude, single-engine "hopper" tests of the Starship (previously known as "BFR") rocket it's designing for the task. Leading up to the tests, Musk has been sharing some technical information about Starship on Twitter, but he also included one little nugget that could be of interest to future Mars passengers.
Transpiration cooling will be added wherever we see erosion of the shield. Starship needs to be ready to fly again immediately after landing. Zero refurbishment.-- Elon Musk (@elonmusk) March 17, 2019
In other words, Musk envisions a rocket that will land on the Moon, Mars, Earth, or wherever, and be able to turn around and take off right away, just like a 737 at your local airport.
Currently, the latest version of SpaceX's Falcon 9 rocket is theoretically able to pull this off, although we haven't seen it yet. Just being able to reuse orbital rockets is such a new thing that the current practice is to take one off the landing pad (or droneship) and check it over before it launches again.
The notion of plane-like rockets also fits with another mind-blowing Muskian promise from a while back, which was that Starship could also be used for super-quick international flights via space.
Whether it's rocketing to Mars or Madrid, this is all likely quite a way off, but it might get off the ground for the first time with some short hops from the SpaceX test site in Texas this week.