Featured Image Source: Elon Musk

SpaceX teams at Boca Chica Beach, Brownsville, Texas are rapidly building Starship SN1, the first flight vehicle that will perform a high-altitude launch of 20 kilometers and will attempt a propulsive landing. A Vehicle Assembly Building (VAB) is under construction simultaneously, the second prototype of Starship - SN2 - will be manufactured in a full enclosed environment. SpaceX teams have been working 24/7 operations. Teams started to stack up the flight vehicle's stainless-steel rings and inner structures that includes propellant dome tank. During this assembly process, each stainless-steel piece that was built and make up Starship SN1 will be welded together as they're stacked (video below). SpaceX is hoping to have the entire vehicle stacked, fully assembled, by the end of February in order to transport it to the nearby launch pad that is about 2 miles away from the assembly facility. If assembly goes well, a static-fire test of Starship SN1’s 3 Raptor engines could occur early March. Starship SN1 is scheduled to perform its first test flight 20 kilometers above Boca Chica Beach sometime after March 16.

The founder and Chief Engineer of SpaceX, Elon Musk, has been spending most of his time since early February working alongside SpaceX employees on Starship production. Last night, he shared that they are currently working on building Starship SN1's nosecone section, which is the very top of the flight vehicle, he Tweeted video of their progress. In the video below, a shiny, mirror-like 301 stainless-steel is being used for nosecone production. Musk previously said that they selected to build Starship SN1 out of 301 stainless-steel because "it’s obviously cheap, it’s obviously fast -but it’s not obviously the lightest. But it is actually the lightest. If you look at the properties of a high-quality stainless steel, the thing that isn’t obvious is that at cryogenic temperatures, the strength is boosted by 50 percent" Musk explained to reporters, "Most steels, as you get to cryogenic temperatures, they become very brittle. You’ve seen the trick with liquid nitrogen on typical carbon steel: You spray liquid nitrogen, you can hit it with a hammer, it shatters like glass. That’s true of most steels, but not of stainless-steel that has a high chrome-nickel content. That actually increases in strength, and ductility is still very high. So you have, like, 12 to 18 percent ductility at, say, minus 330 degrees Fahrenheit. Very ductile, very tough. No fracture issues."

 

Rocket nosecone production in Texas pic.twitter.com/KLWewja9Gn

— Elon Musk (@elonmusk) February 19, 2020

Musk explained other benefits of building a stainless-steel Starship: "I think is quite important, when you consider this as a reentry vehicle. See, here’s the other benefit of steel: It has a high melting point. Much higher than aluminum, and although carbon fiber doesn’t melt, the resin gets destroyed at a certain temperature." He added, "So typically aluminum or carbon fiber, for a steady-state operating temperature, you’re really limited to about 300 degrees Fahrenheit. It’s not that high. You can take little brief excursions above that, maybe 350." Starship is designed to become a fully reusable launch vehicle that must be capable of withstand the highest temperatures upon the fiery atmosphere reentry when returning from space, in order to be reused. When asked where the stainless-steel comes from Musk responded, "It’s just 301 stainless. Let me put it this way: 304 stainless is what they make pots out of. There’s plenty of it." This makes Starship production a bit more cost effective compared to the production of other rockets, "The carbon fiber is $135 a kilogram, 35 percent scrap, so you’re starting to approach almost $200 a kilogram. The steel is $3 a kilogram." So, stainless-steel is the most affordable option that offers strength and heat-shield properties.

SpaceX has also been rapidly building tents to support Starship production in an enclosed environment, to allow teams to work without the weather intervening. A massive Vehicle Assembly Building (VAB) is under construction, Musk shared a video of the building that will also serve to protect spacecraft during hurricane season.

High bay for stacking Starship engine bay, propellant tanks & fairing (fka nosecone) sections is almost done! pic.twitter.com/G9h0430ns2

— Elon Musk (@elonmusk) February 20, 2020

VAB looks tall enough to support Starship and also the vehicles first-stage which is a massive Super Heavy rocket booster. Starship will require a Super Heavy rocket to get out of Earth's atmosphere. The company aims to build Super Heavy as reusable and reliable as their Falcon 9 rocket that is capable of using the power of its own engines to return from space, landing vertically on autonomous droneships at sea. The final version of Starship will be fully reusable. There is still a lot of work SpaceX will do before the development of the rocket-spaceship duo, first they will build many prototypes. Musk said at least 20 Starship prototypes will be tested at Boca Chica, these will be used to test different features that will aid in the development of a space ready Starship.