China's Space Program Thread II
- Thread starter Blitzo
- Start date
Engines from all countries including US such as RS-25, RS-68 and F-1 are "static", having only one quoted figures.
SpaceX works in a way opposite to the rest of the industry. Other companies have a specification of their payload of a rocket, the engines would have a clearly defined performance spec. So all these specifications are static. SpaceX works by NOT having a promised specification. It use whatever available engine thrust to provide whatever available rocket payload. SpaceX does not need to wait for an engine deisgn to reach its full potential (corresponding to the static of others) to go public.
It is just a common business trick like all mobile phone makers. My friend worked in the phone business, he said the phone makers have all sorts of upgrades available, but they never release them all together at the same time, they split them in small batches. In every batch they use the small upgrade as selling point.
Why the others don't do the SpaceX way? Because their customer (NASA) has a clear requirement on the performance.
Why SpaceX can do what it is doing? Because SpaceX customers are at the mercy of whatever SpaceX give them.
Bottom line is that there is no magic that SpaceX is able to squeeze potential. It is just an optical illusion. What others do is they give you 100 dollar at once. SpaceX gives you 10 dollar 10 times. Then you felt you got more from SpaceX.
I think that tacoburger was talking about how an engine like Merlin has stayed in active development for quite some time (1A,B,C,D,FT etc) while its LV was operational.
by78
General
Tianbing Technology has successfully completed the first long-duration full-system test run of a batch-produced TH-12 engine. The test run featured multiple engine starts and shutdowns, with the cumulative test duration being 200 seconds and the single longest run being 100 seconds.
TH-12 is a 110-ton LOX/Kerosene re-usable engine intended for the Tianlong-3 rocket and features a 3D-printed combustion chamber and turbine discs.
TH-12 is a 110-ton LOX/Kerosene re-usable engine intended for the Tianlong-3 rocket and features a 3D-printed combustion chamber and turbine discs.
by78
General
Another supplier (LightYear Exploration Technology) for stainless steel propellant tanks.
Lightyear Exploration Technology has successfully completed a pressure test (at room temperature) of its 225m-diameter stainless steel propellant tank. Low-temperature tests and axial compression tests will follow.
The analog may not be perfect but it is IMO appropriate if the bench mark is about the final technical achievement of the design.
Let's say Merlin FT reached the full potential of the design as the name Full Thrust suggested. It is equal to RS-25's spec 190 ton force sea level. For SpaceX, they don't need to wait for FT to go to the market, they can use the early variant A,B,C,D already to make money but with a lower total payload capacity of Falcon 9. For RS-25 it is not possible to use early low thrust variants to make business, because the only business they have is the contract of the shuttle that demand the 190t (like FT).
So Falcon 9 is operational much "earlier" compared to the shuttle in multiple steps, it gives the impression of continious improvement. In my analog, Merlin FT and RS-25's 190t are the 100 dollar, SpaceX delivered 100 dollar in five 20 dollar bills over many years, while RS-25 delivered one 100 dollar bills at once.
But if the bench mark is about how early one can get some money, then SpaceX is ahead. It is all about business environment, not about technical prowess. SpaceX wouldn't be able to squeeze anything more out of RS-25, just like it won't be able to further squeeze Merlin FT, both have reached their technical limit.
Merlin stayed in active development is because before FT it is essentially making money out of an alpha, beta version of SW. Nothing wrong with it, but it should not be mistaken with technical achievement or approach that others should emulate.
[addition]
Use YF-100 as example, if CASC operate commercial launches, it could have pushed YF-100 in the launch market early on before it reaches 120t, then improve its thrust to 120t in later variant, then further to 130t as of today. Then we would be seeing the same thing in CASC. Remember Falcon 9 had lots of explosions earlier, SpaceX didn't wait for reliability before they take in launch orders. SpaceX let the insurance company to pay for the reliability. One can start something operational in 80% reliability and reach 95%, or start from 95%. The word operational isn't everything. However, CASC will not take that kind of risk considering their mission demands.
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by78
General
as per CCTV
The electromagnetic ejection microgravity experimental device mentioned a few days ago is just the beginning. The experimental time of the currently built device is 4 seconds. In the future, a device with an experimental time of 20 seconds will be built. It is necessary to build an 800-meter -long electromagnetic ejection track.
