Today SpaceX experienced another explosion at its South Texas launch site in Boca Chica, Texas. Once again, the explosion occurred during a cryogenic pressure test, where a prototype was pressurized with liquid nitrogen to see how it was holding up. This time, it was the test tank for the seventh Spaceship prototype (SN7), which was being deliberately pressurized to the point of failure, also known as. “Tested to failure”.
This was the second cryogenic pressure test to fail with the SN7 test tank, the previous one was done about a week ago (June 15, 2020). The purpose was to test a new type of stainless steel (304L Steel) and a new manufacturing technique that SpaceX has been testing. By testing this steel to failure with their test tank, they intend to find out if it is better for the final Spaceship design that the 300 series they have been using so far.
Like the test that was performed on June 15, the second pressure test was performed in the morning after the environmental test was completed the night before. After detecting a leak in the upper dome, the tank exploded, releasing liquid nitrogen and ice particles through the facility as well. The test tank was repaired and resealed so that it could undergo a second round of environmental and pressure tests last night and this morning.
This latest test was captured by the many live broadcasts that monitor the Boca Chica test facility twenty-four hours a day, which includes NASA Spaceflight’s Mary Pointer (aka @BocaChicaGal). The livestream event also featured a panel of NASA Spaceflight members, including Chris Bergin (@Chris B), Jack Beyer (@thejackbeyer), Das Valdez (@KSpaceAcademy), and Michael Baylor (@nextspaceflight).
Things started in earnest about an hour later with the test tank releasing liquid nitrogen from its top, which slowly intensified. Almost three hours and after live coverage began (2h53m24s), the panel noticed an unusual amount of liquid nitrogen coming out of the test tank, followed by nitrogen ice falling from the tank walls. Speculation began that the tank had leaked, as in the previous test.
At 11:37 am, almost three hours after the live broadcast event started (2h59m21s), Mary can be heard saying “there it goes!” The tank exploded from the bottom, leaped about ten meters (33 feet) into the air, and then collapsed onto its side. The entire facility was covered in dense clouds of frozen nitrogen particles, which began to cascade from the site.
Chris tweeted news of the explosion shortly thereafter via NASA’s official Spaceflight Twitter feed, displaying a fourteen-second clip of the explosion titled: “RIP SN7 Test Tank. Thanks for the data! Soon after, the The panel confirmed that the test tank had traveled vertically as a result of the explosion, prompting the blatant observation: “10 meter jump. Hopper: Nice try, Junior!
This of course is a reference to the Spaceship Hopper (aka. Starhopper) vehicle, which completed the jump tests last summer. These tests, where a single Raptor engine was integrated into a reduced prototype, concluded with the Starhopper Successfully flying at an altitude of 150 m (500 ft), moving laterally and then making a soft landing on another platform.
Like repeated testing using SN helmet prototypes, the goal here is to test the technology and manufacturing methods that will be used to create the Spaceship and Super heavy Launch System This iterative rapid prototyping approach enables SpaceX to rigorously verify all the different elements of the flight system prior to flight testing.
Once they are confident that an SN can pass concentration, SpaceX hopes to perform a 150m (500ft) jump test with a single-engine prototype. Once completed, the company will proceed with a 12-mile (20 km) jump test, as well as a supersonic reentry and controlled landing, using a three-engine prototype.
Along with the development of Super heavy booster, this will be the last step before a full-scale orbital flight with six Raptor engines takes place, followed by the completion of the SpaceshipThe design and start of commercial production.
Further reading: Twitter