SpaceX’s Interplanetary Transport System is a vast system of different rocket architectures with one goal in mind: start a colony on Mars. One of the key technologies of that plan is, obviously, the rocket — and in a new paper published in the journal New Space, SpaceX CEO Elon Musk gives a little more detail that illustrates how a rocket bound for Mars is not a far stretch of the imagination for the company.
The first part of that rocket is the engine itself, which SpaceX is calling the Raptor. “The Raptor engine is going to be the highest chamber pressure engine of any kind ever built, and probably the highest thrust-to-weight,” Musk writes.
Musk explains that Raptor is a full-flow staged combustion engine, capable of maximizing momentum out of the given source fuel and oxidizer. It possesses a pretty unconventional design: “Compared with when used close to their boiling points in most rockets, in our case, we load the propellants close to their freezing point.” The technical reasons behind why this makes sense are a bit strange for anyone who isn’t a rocket scientist, so allow me to basically explain that this makes the rocket work more efficiently.
Then we get to the rocket booster itself. If you love watching the Falcon 9 booster pull off vertical landings, you’re going to love this baby.
“In many ways, the rocket booster is really a scaled-up version of the Falcon 9 booster,” writes Musk. “There are a lot of similarities, such as the grid fins and clustering a lot of engines at the base. The big differences are that the primary structure is an advanced form of carbon fiber as opposed to aluminum lithium, we use autogenous pressurization, and we get rid of the helium and the nitrogen.”
Each booster uses a staggering 42 Raptor engines, but given that the rocket is supposed to get the ITS spacecraft out to over 5,200 mph, we’ll give Musk a pass on the excess. And it’s worth remembering that because Mars has a thinner atmosphere than Earth, it takes a lot less power to leave the atmosphere and get back into space.
“We can max out the number of engines because we do not have to leave any room for gimbaling or moving the engines,” writes Musk. “This is all designed so that you could actually lose multiple engines, even at lift-off or anywhere in flight, and still continue the mission safely.”
Hopefully, Musk means that as a possibility and not a likelihood, but regardless it’s nice to know SpaceX is providing a threshold in which things can go wrong and the ITS architecture can still get people to the red planet.