Beijing time on December 10, 6:45, SpaceX's starship validator SN8 finally conducted a lift-off test, the first challenge of high-altitude flight, which is the largest scale test flight of the prototype starship so far, the maximum height of 12,500 meters. The previous Starbug, SN5, SN6 are only 150 meters low altitude jump, and this time directly up to the kilometer level. Not only that, SN8 also challenged for the first time "belly slap dive" and other critical attitude test - really let a person long eyes. This up to 50 meters high, 9 meters in diameter, weighing hundreds of tons, 680 tons of thrust "stainless steel bucket", interpretation of a aerodynamic aviation blockbuster.
What amazes people is not the posture of SN8, but the amazing vectoring capability of the Raptor engine fitted to SN8. Vectoring simply means that the engine will move around. Raptor" that vectoring amplitude and square dance ah.
But unfortunately in the end SN8 did not land successfully, touching the ground at that moment exploded, and later Musk gave the reason: because the methane tank pressure is not enough, resulting in insufficient supply of methane to the engine. The reason why you can see the engine spewing green flames is because the engine uses methane to regenerate the cooling, but because the methane supply is insufficient to directly cause the regenerative cooling does not reach the working flow, so the cooling capacity is seriously insufficient, and the consequence is that the engine's inner nozzle to the "burn", which led to the combustion of the copper on the nozzle, which involves high school color reaction: the color of the metal combustion
Because the methane supply is insufficient to cause the engine thrust to be drastically reduced, it is not possible to see the engine's green flame.
The lack of methane supply led to a sharp drop in engine thrust, and the result of this drop in thrust was that the SN8 was not successfully reduced to a safe speed. Despite the imperfect ending, the process was quite stunning, and I would call it a failed success.
It's OK that the SN8 blew up, because it was a big breakthrough. As mentioned earlier, the SN8 was the first in the series to fly this high, and the first to do an action attitude, laying very much of the groundwork and experience for what was to follow. Amazingly, the successor to the SN8, the SN9, has also been built and will be put on the guillotine next week for testing. If it succeeds, it will join the Starbugs in the history books near the factory. If it fails, there's no more of it, and we all know that.
The SN9 looks pretty much the same as the SN8, but the SN9 has been upgraded in terms of materials; the SN8 was the last SN to use 301 stainless steel, while the SN9 uses 304L stainless steel, which gives it more strength and reliability.
Throughout the history of the Starship series
On February 28, 2019, the first product of the SN series, the SN1, underwent a pressure test, but exploded in the middle of an overgrowth, and the SN1 became the first SN to fall to the "guillotine". The SN1 and the SN8 were about 9 months apart, and with the SN9 coming next week, the average is once a month. SN9 next week, an average of once a month.
Despite the frequency of the SN series, most of the tests were on tanks, i.e. fuel tanks. So many people think that there is not much technical content. In fact, not only them, but also in the past when I didn't know about spaceflight, I also thought so. Then I realized that the canisters were not low tech at all. We have to make it thin enough because it's light that way, but then we have to make it withstand ultra-high pressure and ultra-low temperatures because that's the nature of the fuel. It smacks of trying to make the horse run fast without giving it grass.
It comes down to working on materials and design, but the materials of starships are fixed and don't bring much variation, so it comes down to design. So the canisters you see aren't just any canisters.
After talking about SN, let's look at the time it took to develop China's most powerful launch vehicle, the Long March 5.
"Long March 5" launch vehicle used by the liquid oxygen kerosene engine YF-100, 1988 began the experimental development, in 1990 to carry out a comprehensive key technology research, in 2000, the state top development, in 2002, the first complete test vehicle. On September 20, 2015, the Long March 6 launch vehicle successfully made its maiden flight at the Taiyuan Satellite Launch Center, which was the first time the YF-100 engine was in action. This time, 27 years have passed since the experimental development.
Technically speaking, the YF-100 engine is the most advanced engine. Because it uses the most advanced graded combustion cycle operating principle, the advantage is high efficiency and thrust. The Raptor engine also uses a staged combustion cycle, but it is more advanced. Because there are two types of graded combustion cycles, the Raptor uses the most difficult kind. The Raptor is also the world's first engine to use a full-flow staged combustion cycle.
In terms of launch vehicles, we all know that it took 10 years for the Long March 5 rocket to make its maiden flight. But in fact, it took even longer. The Long March 5 was demonstrated in 1988, and it wasn't until 2001 that it began pre-research, followed by a project in 2006 and its first flight in 2016. That's 15 years past development time. And according to Musk's narrative, the Starship will make its maiden flight around 2023, which, if it goes well, would put SpaceX's development of the super-heavy launch vehicle at only about four years.
Of course, the Long March 5 is a rocket that already exists, and to give an example of one that doesn't exist yet: the Long March 9
Our Long March 9 super-heavy launch vehicle was formally programmed for research in 2016, and will make its maiden flight in 2030 at the earliest, with the engine and the rocket body currently under study. If it goes well, then it took us 14 years to develop the super-heavy launch vehicle.
If all goes well, then one is 4 years, one is 14 years. Of course, I actually think that 4 years to develop a starship is a little bit hanging, but this time even if it is doubled we are still slower than them, doubled 2 times slower, so China's aerospace road is a long way to go, we can not be in a hurry, and steady and steady in order to go farther, fly higher! Thank you for reading!