On September 28, 2019 in Texas, Elon took us on a windy ride to discuss Starship, the space beast that will hit Mars and make space travel a thing. Just as Elon wanted it to be, the show was inspirational, taking us from rhetorical questions about our existence to complex engineering designs and of course Musk’s “space geek terms”. Saturday proved to be a reminder that Elon’s vision about the future of human civilization is that of our legendary Carl Sagan. SpaceX focuses on transforming humans into a spacefaring civilization, and here’s a sneak peak on how they plan to achieve this goal. These are the questions that Elon answered during his presentation.
What is the purpose of Starship?
The purpose of Starship is to make space travel affordable. Thanks to its reusability, Starship will operate at a fraction of the current traditional rockets. In Elon’s farsighted mind, the only way to make space travel accessible is to make it like air travel. He mentioned that reusability is what will make space travel the norm. Imagine if you are to build a plane or a car every time you have to go somewhere! After 50 years since the moon landing, we can finally say that humans no longer have to get rid of the rocket after it launches every time. This space beast is designed to be fully reusable, and all its design considerations revolve around that fact.
Starship will land back at the launch pad to be filled with propellent before its next launch. This “necessary breakthrough” that Elon is achieving is what makes SpaceX special: walking on the edge of scientific impossibility, Elon admitted that this technology is practical only because of Earth’s heavy gravity and thick atmosphere. If it were slightly heavier, this type of technology wouldn’t have been feasible, at least not right now.
What is the next move?
Just like Grasshopper, Starship will climb to an altitude of around 20 km and then land again. Elon said that it will take off in about one or two months, but this can be an optimistic deadline.
How will it land?
As he mentioned, this space beast will be epic when landing because the scientists behind it are using a new approach, which will make Starship look like a skydiver rather than a plane. Watch the video below to see how it will happen!
Hence, Elon chose to describe this scene as a “controlled fall”, and the crows got exciting wanting to see it in action.
How much is SpaceX spending on Starship?
Surprisingly, only 5% of SpaceX’s resources are being invested in this project. Most of the focus is going to Falcon and Dragon since they are behind schedule on many projects for NASA.
What are the Specs of Starship?
When you look at the vehicle and all the videos showing how it launches and lands, you’d imagine it being part of a thoroughly planned CGI sci-fi movie. However, once we break Starship into subassemblies, you will see the engineering miracles lurking in the shadows of this mighty beast.
With 9 meters in diameter, Starship’s body has a tremendous height of 50 m. Its dry mass is around 120 tons, and if they can squeeze the weight,, Elon plans to reach 110 tons.
Raptor Engines inside the body
The body has a total of 6 raptor engines: three sea-level and three vacuum engines. The sea-level engines are already installed in the prototype that was standing next to Elon during his presentation. The sea-level engines will move up until a 15-degree angle from its original state in order to steer the rocket. On the other hand, the vacuum engines will be fixed in place. Raptor engines will be also used in the booster, Super Heavy.
Of course, when we mention engines, we should mention the propellant, and in this case, mostly oxygen. For every ton of fuel, SpaceX is using 3.5 tons of oxygen. The raptor engine is powered by liquid oxygen and subcooled liquid methane. Unlike the Falcon 9 architecture, which includes the merlin engines, the Starship architecture will allow SpaceX to use more oxygen than fuel, especially for vacuum travel since there is no air.
Here is where things get materialistic. The heat shield is what allows the rocket to protect itself against the thick atmosphere when it comes in for entry. Hexagonal ceramic tiles will act as a shield to the steel, and it is crack resistant and very light. The choice of material is vital to the success of the mission.
Stainless Steel is the New Carbon Fiber
Elon Musk calls it the best engineering design ever. They switched back to 301 Stainless Steel and dumped Carbon Fiber for valid reasons. Ironically, this material’s characteristics proved to be lighter than Carbon Fiber. First, it has a high melting temperature unlike aluminum or carbon fiber, and for entry, this makes it ideal. This way, the cooler side of the rocket when it re-enters the atmosphere doesn’t need shielding, and the shielding of the hotter side becomes much lighter. However, the real part of the deal is at cryogenic temperatures. Unlike other types of steel, 301 stainless steel won’t get brittle in the cryogenic range, and it has the same effective strength as aluminum lithium and better strength-to-weight ratio. Fortunately, the cost of 301 stainless steel is 2% of the cost of Carbon Fiber, according to Mr. Musk!
This is also a farsighted move. Steel is easily weldable and modified. Anyone can reuse the steel if it is needed for another task on Mars, just like the raptor engine which is adaptable on Mars because methane is abundant on the red plant. Smart moves SpaceX.
Now for the grand finale, Super Heavy is the booster attached to the main body. With its 68-meter height, it makes Starship stand 118 meters tall. It can take up to 37 raptor engines, and the minimum number of engines is around 24. SpaceX needs that much engines because of thrust. For reusability purposes, the booster needs to have very high thrust-to-weight ratio, and in this case, around 1.5.
Check out this video to see how the whole action will be like!
Inspirational on many Levels
This was a nice deep dive into the engineering behind Starship. Elon’s presentation was indeed inspirational on many levels. All generations are excited to see where this is going, and it will be indeed epic to see human beings have access to space travel. September 28, 2019 is a special day for Elon, and probably the best inspirational day they he can offer. It is the 11th anniversary of the first time SpaceX reached orbit. It was already the first launch of Falcon 9, and if it weren’t for its success, SpaceX would have gone bankrupt. Throughout the presentation, Elon kept mentioning many of his other failed attempts while smiling. Nothing can be as inspiring as someone talking about the failures he or she has been in. In Elon’s case, he even has bloopers of his failures taped! Mr. Musk, that did inspire everyone watching your presentation!