GETTY IMAGESCHRIS SAUCEDO

In January, [Popular Mechanics] ran an exclusive interview with Elon Musk in which he explained, for the first time, his full thinking—and the complex engineering questions—behind his decision to construct SpaceX’s Starship rocket and booster with stainless steel. The previous design for the rocket (which was then known as the BFR) had called for carbon fiber, but Musk recalculated and went with steel due to its durability, cost-effectiveness, and ductility.

Here, in a continuation of that interview, Musk goes deep on what it takes to actually travel beyond orbit and into space. Also, it sounds like Mars will have a nice park.