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SpaceX teams in South Texas are preparing to conduct a ‘burst test’ of a Starship tank referred to as SN7.1. The tank was given that identifier because its predecessor SN7 was a dome tank that popped during a proof test –SN7.1 will have the same fate, engineers are preparing to intentionally destroy the test tank. They will push the stainless steel tank to its limit during a cryogenic pressure test that is expected to take place this week at the Boca Chica beach launch facility. According to Boca Chica beach closure announcements, SpaceX may conduct the destructive test on Thursday, September 17. The testing window initiates at 9:00 p.m. and ends at 6:00 a.m. Central Time (CDT). There has been a series of thunderstorms in South Texas this week; If the test is delayed due to weather conditions or other issues, back up test opportunities are scheduled for September 21 and 22 from 9:00 p.m. to 6:00 a.m. CDT.
On September 7th SN7.1 tank was transported to the launchpad at Boca Chica. On September 10th, teams conducted a cryogenic proof test to ensure the structure is strong enough to withstand the stresses a Starship would face during flight. The structure must withstand a strength between ~6 bar and 8.5 bar; ~6 bar is needed for orbital flights and ~8.5 bar is the strength that would be safe to carry out crewed flights, according to SpaceX officials.
The tank appears to have passed that test; Engineers moved on to lift Starship SN7.1 onto the Starship launch mount to prepare for further testing leading to the destructive pressure test. A Boca Chica resident captured footage of teams mounting SN7.1 onto the test stand, video below. UPDATE: SpaceX teams may conduct a test as soon as tonight, unclear if it will be the 'burst test'.
Another round of SN7.1 testing is currently underway. I still believe the pressurize to failure test is likely slated for later in the week, but SpaceX's plans can change, and the tank could always pop earlier than planned. https://t.co/gFtjaJQVo7— Michael Baylor (@nextspaceflight) September 16, 2020
During the upcoming pressurization test, engineers will fill the dome with liquid nitrogen, which will subject the structure to sub-chilled temperatures while a simulator simulates the Raptor engines force and vibrations. The test will push the limits until the Starship SN7.1 tank bursts. This test is conducted to assess how much pressure the welded stainless-steel can withstand. Previous prototypes were made out of 301 stainless steel, this tank features 304L stainless steel, which will offer engineers insight into what material is best for future use. The company is developing its own stainless-steel alloy mix, so, these destructive tests provide valuable data towards the creation of SpaceX’s alloy.
SPACEX TEAMS LIFT STARSHIP SN7.1 ONTO LAUNCH MOUNT