SpaceX tests 7th Starship test prototype to failure
Capitalism in space: As they had planned, SpaceX has done a tank pressure test of its seventh Starship prototype to failure, destroying the prototype.
This was actually the second test to failure for this tank, which is testing a new stainless steel alloy. The first had only sprung a leak that could be repaired.
Deemed 304L, the type of steel is still readily available off the shelf and only 10-20% more expensive than the 301 alloy SpaceX has used to build all Starship prototypes up to SN7. The biggest change it brings to the table is improved ductility (malleability), particularly at the cryogenic temperatures Starship’s tanks will often be held at. By reducing brittleness, Starships built out of 304L steel should be able to fail far more gracefully by developing stable leaks instead of violently decompressing. In fact, the very same test tank destroyed on June 23rd demonstrated that capability perfectly when it sprung a leak during its first pressure test on June 15th.
During its first cryogenic pressure test with liquid nitrogen, SpaceX CEO Elon Musk revealed that the SN7 test tank managed to reach 7.6 bar (~110 psi) before it began to leak – technically satisfactory for orbital Starship launches with an industry-standard 25% safety factor. Thanks to the general flexibility of steel, including the new 304L alloy SN7 was built with, SpaceX was able to simply repair the leak it identified, readying the test tank for a second cryogenic pressure test barely a week later.
Below the fold are two videos showing this second failure. Unlike earlier tests using different alloys, the tank does not go flying hundreds of feet into the air. The rupture seems more gentle, if I can use such a word for such a failure.
They have another tank ready to go, so testing should proceed quickly even after this test failure. And they also are prepping the full scale #5 Starship prototype for testing, which if all goes well will include actual test hops.
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Capitalism in space: As they had planned, SpaceX has done a tank pressure test of its seventh Starship prototype to failure, destroying the prototype.
This was actually the second test to failure for this tank, which is testing a new stainless steel alloy. The first had only sprung a leak that could be repaired.
Deemed 304L, the type of steel is still readily available off the shelf and only 10-20% more expensive than the 301 alloy SpaceX has used to build all Starship prototypes up to SN7. The biggest change it brings to the table is improved ductility (malleability), particularly at the cryogenic temperatures Starship’s tanks will often be held at. By reducing brittleness, Starships built out of 304L steel should be able to fail far more gracefully by developing stable leaks instead of violently decompressing. In fact, the very same test tank destroyed on June 23rd demonstrated that capability perfectly when it sprung a leak during its first pressure test on June 15th.
During its first cryogenic pressure test with liquid nitrogen, SpaceX CEO Elon Musk revealed that the SN7 test tank managed to reach 7.6 bar (~110 psi) before it began to leak – technically satisfactory for orbital Starship launches with an industry-standard 25% safety factor. Thanks to the general flexibility of steel, including the new 304L alloy SN7 was built with, SpaceX was able to simply repair the leak it identified, readying the test tank for a second cryogenic pressure test barely a week later.
Below the fold are two videos showing this second failure. Unlike earlier tests using different alloys, the tank does not go flying hundreds of feet into the air. The rupture seems more gentle, if I can use such a word for such a failure.
They have another tank ready to go, so testing should proceed quickly even after this test failure. And they also are prepping the full scale #5 Starship prototype for testing, which if all goes well will include actual test hops.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Do we know how many Bar the second test of SN7 got to?
I haven’t heard how high the test of SN7 went. Elon usually tweets the values a few days after (sometimes quicker) so it will probably be released in the next few days. It seems SpaceX ultimately needs to be above 8.4 Bar to achieve the safety margin for manned flight, so hopefully, it will be close to that or higher.
Here is a neat video of Zeus checking out the area in the aftermath.
https://www.youtube.com/watch?v=Bm5hrbLSH2k