Featured Image Source: @SpacePadreIsle via Twitter.
SpaceX is in the process of developing a gigantic Starship that will one day perform voyages to the moon and Mars. The first test prototypes are under construction at the company's South Texas facility in Boca Chica Beach. On April 2nd, engineers conducted a cryogenic pressure test on SN3, the company's third Starship prototype this year. The vehicle was loaded with cryogenic (super cold) liquid nitrogen, and pressurized in order to test out how much pressure the stainless-steel structure could withstand. During the test, the craft is pressurized to the max, as engineers inspect for leaks and hope the stainless-steel structure withstands a pressure strength between 6 and ~8.5 bar. This test aims to put the vehicle into conditions similar to those it would experience during a spaceflight. Though, Thursday's test did not go as planned. The vehicle collapsed, sending shattered steel parts flying off the launch pad's stand. Boca Chica village residents captured the dramatic collapse on video (shown below).
The founder and Chief Engineer at SpaceX Elon Musk, shared via Twitter that what caused the Starship SN3 prototype to collapse during the pressurization test was not a manufacturing error, nor design flaw. "Good news is that this was a test configuration error, rather than a design or build mistake," Musk said. He explained the SN3's collapse was caused because the vehicle's liquid oxygen (LOX) tank was not equally pressurized "to maintain stability with a heavy CH4 (methane) tank." The configuration error in the spacecraft's system did not pressurize the structure equally. "Not enough pressure in the LOX tank ullage to maintain stability with a heavy load in the CH4 tank. This was done with N2," he said. The SN3 vehicle was filled-up with cryogenic nitrogen (N2) during the test, instead of propellant.
"...Good news is that this was a test configuration error, rather than a design or build mistake. Not enough pressure in the LOX tank ullage to maintain stability with a heavy load in the CH4 tank. This was done with N2."
Pretty much. Good news is that this was a test configuration error, rather than a design or build mistake. Not enough pressure in the LOX tank ullage to maintain stability with a heavy load in the CH4 tank. This was done with N2.— Elon Musk (@elonmusk) April 5, 2020
Starship is in its early phase of development, these types of test failures are expected. Each prototype test provides SpaceX engineers with important insight on how to improve the craft, and what configuration in the spacecraft's system need to be double checked and re-configured on future tests. Future prototypes will incorporate all the lessons the company learned from previous Starship tests. In late December, Musk mentioned he expects to build 20 Starship prototypes, "but each SN will have at least minor improvements, at least through SN20 or so of Starship V1.0." The company has started a production line of Starships at the SpaceX Boca Chica factory. Manufacturing quickly enables them to speed up the testing and development process. Currently, Starship SN4 is under assembly. SN4 will go through similar tests as SN3 and if it passes all tests, the craft will conduct a test flight. The first test flight is expected to be powered by three Raptor engines and fly to an altitude of 150 meters. Last night, Musk shared a photograph of the next-generation Raptor engines that will be integrated to a future craft that will perform a debut flight this year.
Raptors pic.twitter.com/oycjgNI8HE— Elon Musk (@elonmusk) April 5, 2020
About the Author
Evelyn J. Arevalo joined Tesmanian in 2019 to cover news as a Space Journalist and SpaceX Starbase Texas Correspondent. Evelyn is specialized in rocketry and space exploration. The main topics she covers are SpaceX and NASA.