Featured Image Source: @NASASpaceflight via Twitter.
SpaceX’s next-generation spacecraft is under development at the company’s South Texas facility located in Brownsville, Boca Chica Beach, TX. The facility was transformed into a factory to manufacture a production line of many stainless-steel Starships to test out different features. NASA announced this week, Starship is selected to perform missions to the moon under the agency’s Artemis program. The company is working on the fourth Starship prototype, referred to as Starship SN4, as SN5 is under construction. Engineers aim to develop a craft that could withstand high stress of pressurized propellant and flight. To test the vehicles’ strength, they performed a cryogenic pressure test. On April 26, SpaceX teams at Boca Chica conducted a cryogenic pressure test. During the test, SN4 was filled with sub-cooled liquid nitrogen to determine if the stainless-steel structure can withstand high pressure and test out weld quality strength. Since November 2019, three Starship prototypes were destroyed during pressurization. The founder and Chief Engineer at SpaceX, Elon Musk, shared Starship SN4 passed the cryogenic pressure test at SpaceX Boca Chica. It is the first time a large-scale prototype withstands a high pressure test. Musk previously said Starship needs to withstand a pressure in between ~6 and ~8.5 bar strength; A ~6 bar is needed for orbital flight and ~8.5 bar is needed for crewed flights. Starship SN4 withstood pressure of 4.9 bar, or 4.9 times the atmospheric pressure of Earth's surface – “4.9 bar. Kind of a softball tbh [to be honest], but that’s enough to fly!” Musk said.
4.9 bar. Kind of a softball tbh, but that’s enough to fly!— Elon Musk (@elonmusk) April 27, 2020
SpaceX is getting close to performing a debut test flight! Starship SN4 will be the first ‘large-scale’ prototype to be launched. The first launch will be a 150-meter-high ‘hop’ test above Boca Chica Beach. Engineers are expected to also attempt to land SN4 on a nearby landing pad. Engineers are actively preparing the craft ahead of launch. SpaceX is preparing to conduct a ‘wet dress rehearsal’ (WDR) to then conduct a static-fire test of SN4’s Raptor engine. Raptor engines are fueled by cryogenic methane and liquid oxygen. A WDR is the process of fueling the vehicle to simulate a launch countdown without launching it. This prepares the vehicle to conduct a static-fire test, which is a pre-flight preparation of the Raptor engine. During a static-firing, the engine will be ignited as the vehicle is held down to the launch pad with hold on clamps. After a successful Raptor ignition, Starship SN4 will be ready for a debut launch.
Last night, Boca Chica Village residents live-streamed activity at the launch pad. It appears the company initiated (or attempted) a WDR test on the SN4 vehicle. As seen in the video above, a flare stack is throwing out fire, which is an indication that SpaceX filled up Starship SN4’s fuel tank with chilled methane and liquid oxygen. The flare stack is used to burn out excess methane.
Boca Chica road closure announcements indicate SpaceX will conduct vital tests in the coming days. The next test is expected to be a Raptor engine static-firing. Road closures are scheduled for May 3 to May 5 from 9:00 p.m. to 6:00 a.m. Central Time.