SpaceX ramps up Raptor engine tests
Capitalism in space: SpaceX has conducted another Raptor engine test, this time running the engine at full power.
“Raptor just achieved power level needed for Starship [and] Super Heavy,” Musk tweeted just after 3 a.m. EST (08:00 GMT) Feb. 7.
Musk did not say how long the test was or if it was at full power. The Feb. 3 burn was only about two seconds and at about 60 percent power. However, he said the latter test reached a chamber pressure of 257 bar, or about 3,700 pounds per square inch, and an estimated force of about 172 metric tons with “warm propellant.”
Musk has said that they will be doing hopper test flights with their Starship prototype this spring, but they can’t do that until they have three working Raptor engines. It seems to me that it will be at least a few months before this engine is tested sufficiently to be ready for flight. Then they need two more finished engines.
Don’t expect the first Starship hopper flights for at least six more months, if that soon.
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Capitalism in space: SpaceX has conducted another Raptor engine test, this time running the engine at full power.
“Raptor just achieved power level needed for Starship [and] Super Heavy,” Musk tweeted just after 3 a.m. EST (08:00 GMT) Feb. 7.
Musk did not say how long the test was or if it was at full power. The Feb. 3 burn was only about two seconds and at about 60 percent power. However, he said the latter test reached a chamber pressure of 257 bar, or about 3,700 pounds per square inch, and an estimated force of about 172 metric tons with “warm propellant.”
Musk has said that they will be doing hopper test flights with their Starship prototype this spring, but they can’t do that until they have three working Raptor engines. It seems to me that it will be at least a few months before this engine is tested sufficiently to be ready for flight. Then they need two more finished engines.
Don’t expect the first Starship hopper flights for at least six more months, if that soon.
The support of my readers through the years has given 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. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
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. Even today NASA and Congress refuse to 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.
Please consider supporting my work here at Behind the Black.
You can support me either by giving a one-time contribution or a regular subscription. There are five 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:
5. Donate by check, payable to Robert Zimmerman and mailed to
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c/o Robert Zimmerman
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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. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.
Word on NSF yesterday centered around 90% power for less than 10 seconds, probably around 6. Also, shock and awe that this test followed the first by only two days. Musk says it will be a while (Musk time?) for full power. But this is sufficient for the hopper and apparently the first prototypes.
No speculation yet on “full duration” firing, whatever that might mean for hopper engines. And no word on the overall test plan, but noting that this is a full-scale Raptor fresh off the production line. (I don’t think I’d call serial number one a “production model,” though. Close.) Depending on results, this engine may get more testing than hopper engines two and three, and maybe a spare for the hopper. I don’t expect a test-to-destruction until after the hopper has its engines. The hopper engines will get some restart testing, but again I expect that engines for prototypes will get a lot more of that.
By way of comparison, Boeing sets aside two airframes for static testing of new airliners, one for wing deflection (usually to destruction, although they didn’t do that for the composite wings of the 787), and one for fatigue testing, with simulated take-off and landing cycles in excess of expected airframe life. That seems a prudent approach for high reliability and reuse.
Diane Wilson wrote: “I don’t expect a test-to-destruction until after the hopper has its engines.”
I don’t expect any intentional tests to destruction on rocket engines. It tends to be hard on the test equipment, and it does not reassure customers.
https://www.youtube.com/watch?v=kBBIbTUvWnY (9 minutes: “Test firing a new rocket engine (and watching it explode)”)
I once tested some standoffs for a spacecraft instrument, and we decided that while we were on the shake table and finished with the planned test, we would test to destruction just to see how well we had designed our standoffs, but it gave no necessary engineering information. When NASA heard that the standoffs had broken, they were upset, and we had to calm them down, because they hadn’t realized that we had deviated from the test plan.
I have stuck to test plans ever since, and made sure to design the plans to test only what was necessary. This is a case where going above and beyond is not such a good idea.
Boeing testing wings and airframes to destruction may have given them important engineering feedback and reassured customers that their purchases would last longer than the designed economic lifetime.
Test-until-destruction and fatigue testing are done with aircraft because aircraft are reused. That hasn’t been done with rockets because rockets didn’t get reused, until SpaceX. And New Shepard, which takes months between re-use; Musk certainly plans faster turn-around than that.
We’ll see. SpaceX seems intent to shake up the rocketry industry with more than just pricing.