SpaceX is rapidly building the fourth prototype of Starship in Texas

Featured Image Source: @BocaChicaGal via Twitter.

SpaceX's mission is to transform humans into a multiplanet species. Engineers are in the process of developing a massive spacecraft. The two-stage vehicle consists of a spaceship called Starship, and a rocket booster called Super Heavy. The company is in the initial phase of developing the craft. SpaceX is rapidly building the fourth Starship prototype, referred to as SN4, at its South Texas assembly facility located in Boca Chica Beach. The rocket company operates 24/7 to speed up the spacecraft's development. Rapid manufacturing and iteration enable the company to test out different features that will aid in the creation of a space-ready Starship. The vehicle is made of stainless steel, previous prototypes underwent a series of pressure tests to determine if the structure could withstand high-stress conditions experienced in-flight. Two prototypes imploded, giving engineers insight into how to improve the vehicle. Elon Musk, founder and chief engineer at SpaceX, stated that manufacturing a production line of Starship will enable the rocket company to speed up the spacecraft's development.

"A high production rate solves many ills. If you have a high production rate, you have a high iteration rate."

Musk said, "For pretty much any technology whatsoever, the progress is a function of how many iterations do you have, and how much progress do you make between each iteration. If you have a high production rate then you have many iterations. You can make progress from one to the next." SpaceX aims to conduct a series of test flights at Boca Chica with a fully-assembled Starship. The first flight is expected to be a 150-meter test, followed by a higher altitude test launch of 20 kilometers. For altitude perspective, the edge of space begins at around 100 kilometers.

Boca Chica village residents have documented the construction progress. In just a couple of weeks, teams in Texas initiated stacking operations of Starship SN4’s stainless-steel structure inside a new Vehicle Assembly Building (pictured above). In the video below, you can see the shiny rings and dome tanks stacked.

Musk recently shared a photograph of three Raptor engines and a newly assembled header tank, which holds Starship’s propellant to power Raptor engines. Raptors are powered by a combination of sub-cooled liquid methane and liquid oxygen. Starship’s design has a fuel header tank inside the methane main tank. As shown in the photo below, the main tank features a smaller dome tank to reserve some propellant in order to reliably land the vehicle, while the main tank holds the propellant for ascension.

 

 

Methane fuel tank. / Source: Elon Musk 

The liquid oxygen header tank is located at the very top of Starship’s nose cone (pictured below). "Nose tip has forward movable fins, cold gas attitude control thrusters, header tanks for landing, composite pressure vessels, several large batteries, etc. Placed up there to balance high mass of Raptors & rear fins at the bottom," Musk explained via Twitter. Fuel dome tanks are the most difficult part of the craft to build because these stainless-steel domes must be light enough to not add on extra weight but strong enough to withstand highly pressurized propellant and spaceflight stressors. He says building a Starship dome tank takes teams about a week, "1 or 2 days to tack up and fit steel sheets, 4 days to weld the sheets together, and 1 to 2 days for X-ray inspections and repairs." 

Oxygen tank and nose cone / Source: Elon Musk 

Inside Starship cargo bay. Header tanks mounted in tip of nosecone to offset engine weight at rear. pic.twitter.com/EJSwqMCooA

— Elon Musk (@elonmusk) October 1, 2019

To speed up the manufacturing process, SpaceX has held several hiring events at Boca Chica to fill up four work shifts. According to Ars Technica, the company has over 500 employees and provides warm meals to everyone every four hours for free. The initial goal is to develop a flight-ready Starship capable of performing a high altitude flight and a controlled landing with the power of its Raptor engines.

Raptor engines / Source: Elon Musk