Gold, in dollar terms, has hit a new high. I would like to write about my fantasies as the dollar price of gold surpasses its highs.
The demand for space exploration can only come from a "need". Only by being economically profitable can we move this industry forward. What are the necessary elements for space development to move forward in a big way? It is war and global economic collapse.
1．Space exploration to avoid war
On space exploration to avoid war. When resources and land become scarce due to a future population explosion, one solution is for humans to migrate off-planet, which is an option. However, if the cost of spacecraft and rockets to transport humans is too high, it is more cost effective to steal resources and land from other countries through war rather than sending humans to other planets and stars. If it's cheaper to take them away and not develop space, etc., they will go that way. That means we need to develop cheap spaceships and rockets to prevent a world war.
2．The return to the gold standard due to the collapse of the global economy and space exploration
If there are necessary resources with extremely high unit costs, space exploration and space resources development will pay off economically. As a shortcut to this, I believe that economic collapse and a return to the gold standard are necessary as a catalyst.
The following is explained in a narrative style.
In 202X, the U.S. dollar collapsed. It was the first collapse of a reserve currency in history. After the Nixon shock of 1971, the currency that had been printed on national credit was completely discredited and people woke up from their dreams. The conclusion drawn after weeks of meetings by the leaders of the developed countries was a return to the gold standard.
Once it collapsed, mere national credit discredited the printing of paper, and paper money was once again linked to gold. With the return to the gold standard, at today's prices, gold will soar to 50,000 yen per gram. This has changed the balance between nations. The power of nations with gold mines has increased. Developed countries with no natural resources are venturing into uncharted territory with technology. These are ocean development and space development.
The collapse of the global economy and the return to the gold standard after the global crash forced countries like Japan, which have no natural resources, to turn to the extraction of gold from seawater and the mining of gold from the ocean floor, and to space development. And it drove countries like Japan, which have no natural resources, to extract gold from seawater and mine gold from the ocean floor, and to develop space exploration. The price of gold, which is now worth 50 billion yen per tonne, has allowed the high cost industry of space exploration to take hold.
By analyzing the reflective spectra of asteroids, they could identify asteroids rich in gold from afar, send probes to tow them to near-Earth orbits, and mine them for gold in the vicinity of the Earth. This was called the "space gold rush". This demand led to a surge in space exploration technology and made space transportation technology cheaper.
Looking back, the reason space exploration stagnated for the first half-century after the Apollo program was the result of the Nixon shock of 1971, which decoupled the value of U.S. dollar bills from that of gold. If paper money and gold were linked, humanity would have embarked on ocean and space exploration in search of gold, both on and off the planet.
Showing pictures are Apollo Saturn 5 J-2 rocket engine electrical sequence controller assembly solid state interval timer manufactured by Tempo under NASA contract number NAS 7-101. Timer is highly reliable and accurate using an external resistor to produce the desired time of circuit activation in accord with the engine start and restart operations.
The J-2 rocket engine was restartable in the vacuum of space. The electrical sequence controller is a completely self-contained, solid-state system, requiring only DC power and start and stop command signals.
Pre-start status of all critical engine control functions is monitored in order to provide an “engine ready” signal. Upon obtaining “engine ready” and “start” signals, solenoid control valves are energized in a precisely timed sequence as described in the “Engine Operation” section to bring the engine through ignition, transition, and into mainstage operation. After shutdown, the system automatically resets for a subsequent restart.
そして、このノースロップグラマンの訴えに対し、SpaceX側は、2004年6月にロサンゼルス連邦裁判所にて、ノースロップグラマン社の訴訟はSpaceXに損害を与えることを目的とした「反競争的で違法な行動だ」と独占禁止法違反を主張した。更に、ノースロップグラマンが米軍の政府顧問として、その立場を乱用しているとも主張。2003年3月まで遡り、SpaceX社に対する企業スパイ行為を彼らは行ったと主張した。一連の裁判では、Brian D. Ledahl氏がSpaceX側の弁護士を務めている。
As It was reported in my previous article, the TR-108 is "the first multiple pintle injector rocket engine developed by Northrop Grumman. However, was the "Multiple Pintle Injector" technology implemented for the first time in the world in the TR-108?
In my research, I found no published material to support the fact that "multiple pintle injectors" were being developed during the TRW era, and no hits on patent information. However, it is my opinion that the conceptual design of the multiple pintle injector may have been implemented prior to the acquisition of TRW by Northrop Grumman in 2002. However, it is very likely that the conceptual design of the multiple pintle injector was in place before TRW was acquired by Northrop Grumman in 2002. This is because of the following reasons.
Since the development of the TR-108 was aimed at low-cost new development, it was risky to bring in new development elements.
Although the pintle injector is simpler than other injectors, it is expected that there will be cases where the size of the injector becomes too large to be supplied with propellant by a single pintle injector, or where it is deemed difficult to achieve sufficient capability with a single pintle injector, at which point the concept of multiple pintle injectors could be developed.
The normal pintle injector, in which the injector is realized with a single component, is more unique among rocket engine injector systems.
On the other hand, there is no mention of whether SpaceX is using the Multiple Pintle Injector technology, even at a mere "rumor level" as of July 2020, after a search on the web. (See image below)
Google USA exact match search results (July 2020)
3. Merlin 1D Injector Considerations
Check out the image of the public Falcon 9 rocket taken from directly behind, which mentioned in previous article previous article. The resolution is rough, but there are five different colors on what appears to be the pintle injector of the Merlin 1D rocket engine.
Pintle injector section of Merlin 1D rocket engine
Because of the rough resolution, it is not possible to determine whether these five points are three-dimensional or planar shapes. (If they are flat, they are likely to be active cooling mechanisms or jig attachments; if they are three-dimensional, they are likely to be multiple pintle injectors.) In the previous article, I considered them to be "flat" and thought that the entire area in the figure was a pintle injector. In the previous article, I considered this to be a "flat shape" and thought that the entire area shown in the figure was a pintle injector. Therefore, I judged that the five areas with different colors from the surrounding areas were "active cooling mechanisms or jig attachment areas.
However, this arrangement is such that the four points form a rectangle around the central point. It is not incongruous to think that the multiple pintle injectors are arranged like the TR-108 (the TR-108 has an overall hexagonal shape with seven points). Also, in the image released by the U.S. Air Force shown first, it looks like the same hexagonal shape as the TR-108, although it is unclear. Thus, there is a great possibility that the Merlin 1 rocket engine is equipped with multiple pintle injectors.
Merlin1A Engine with Single Pintle Injector
At least for the Merlin 1A (34.67t (340kN) thrust) of the Falcon 1 rocket, the image shows that it is a single pintle injector. (See the image above.) It is a single pintle injector as shown in the image below, and the center of the pintle injector has a copper alloy metallic color, which may be an active cooling mechanism to cool the pintle tip itself, or a jig attachment or fixture. There is also a possibility that this part itself is a pintle injector, as it is surrounded by a unit.
The advantages of converting the Merlin 1D rocket engine to multiple pintle injectors are as follows, as far as the author has considered.
At the Merlin1D rocket engine scale (thrust: 100 tons (981 kN)) used for Falcon 9, the thrust is about three times that of the originally developed Merlin1A. Rather than installing and operating a large actuator for a single pintle injector with a face shutoff function to keep up with this increased thrust, it would be better to install a face shutoff function for each of the five or four multiple pintle injectors. This may lead to a reduction in the weight of the system.
By providing the face shutoff function to the multiple pintle injectors, there is no need to develop a new single pintle injector system with a large face shutoff function. Based on the rocket engine thrust, the size of the system can take over the assets of the previous scale pintle injector design, and the new rocket engine can be developed with minimal changes.
If a throttling function for surface landing is to be provided, as in the case of the Falcon 9 first stage, a multiple pintle injector system will be advantageous. The reason for this is that rather than using a single large pintle injector to control the throttling, it would be much easier to control the thrust by dividing it into multiple injectors and controlling each of them. For example, if you want to operate at 60% thrust, you can simply operate three of the five multiple pintle injectors at 100% throttling and two at 0% throttling.
Having multiple pintle injectors gives you more options in case of failure, and increases the reliability of the engine.
Considering these estimates, we can see that the TR-106 rocket engine (LOX/LH2, 294.9t (2892kN) thrust) and the TR107 rocket engine (LOX/ RP-1, 499.66t (4900kN) thrust) were developed before the TR-108, which used multiple pintle injectors, and Tom Muller was involved in their development. RP-1, thrust: 499.66t (4900kN)).
From my research, I found that at least for TR-106, a single large pintle was used, although it was a liquid-gas mixed injector. The TR-107, however, is unknown. If the TR-107, which is a large booster with a thrust approaching 500 tons, is a multiple pintle injector, it is highly likely that SpaceX, led by Tom Muller, will use this technology.
TR-107 Rocket Engine Cross Section and Single Pintle Injector
On the other hand, as shown in the previous article, there is a possibility that the part of the Merlin 1D is an active cooling mechanism or a jig connection for mounting. The reasons for this are as follows
Increasing the number of pintles makes the mechanism more complex.
The large TR-106, developed during the TRW era, was equivalent to about three times the thrust scale of the Merlin 1D. However, it used a single large pintle.
Although it has won a number of contracts for projects in which U.S. taxpayer money has been invested, SpaceX is a private company that, unlike NASA, is not a purely national research and development organization. It is also researching and developing its own rockets in the free market. As I reported in my previous article, "SpaceX's Patent Strategy and China's Unauthorized Use of Patent Information," SpaceX's competitors in rocket development are not only corporations, but also countries around the world, including Russia and China, including those who would overstep the framework of patents. Therefore, SpaceX has chosen not to patent its technology in order to avoid being taken over.
This policy of not obtaining patents is a means of securing an advantage over others by keeping the contents of the technology secret, just like the manufacturing methods of Coca-Cola and KFC, and as long as this policy is taken, it is unlikely that the details of the technical contents of the Merlin rocket engine will be disclosed in the future.
Therefore, I am not sure if there will be an opportunity to verify these inferences in the future, but from the current public data, I think it is highly likely that the Merlin 1D engine is equipped with an active cooling system or multiple pintle injectors.
References
[1] Los Angeles Air Force Base, Home of Space and Missile Systems Center, 9th January, 2020
The TR-108 rocket engine, the first large rocket engine developed after TRW was acquired by Northrop Grumman, is equipped with a very unique "Multiple Pintle Injector". The TR-108 rocket engine, which was the first large rocket engine developed after the acquisition of Northrop Grumman, features a very unique "multiple pintle injector" technology, which allows multiple pintle injectors to be installed when the propellant supply from a single pintle injector is too large or when it is difficult to achieve sufficient engine capacity with a single pintle injector.
1. Development Background: MDA's Liquid Rocket Booster Development Program
The U.S. Missile Defense Agency (MDA) is also developing a targeted ballistic missile to simulate a ballistic missile for missile defense (MD) evaluation. The Northrop Grumman TR-108 rocket engine has been developed as a liquid rocket booster for targeted ballistic missiles.
Most of the target ballistic missiles have solid-fuel rocket motors, but the reason for changing to a liquid rocket booster was to simulate the ballistic missiles of the East. Since most of the traditional ballistic missiles in the East use liquid fuel propellant, they wanted a liquid rocket booster stage to simulate a liquid booster ballistic missile for future testing and evaluation. Thus, the TR-108 was developed as an upper stage engine for military use. Northrop Grumman was awarded a three-year, $30 million contract.
There has been no information since then on which target ballistic missile the TR-108 was installed on. However, among the target ballistic missiles operated by the MDA is the Hera target, which was first developed as a target ballistic missile in 1992 and was first launched in 1995. Hera is the second and third stages of the retired Minuteman II ICBM. Hera is also used as a sounding rocket by the U.S. Air Force.
Hera 標的用弾道ミサイル
Length: 11.9 m (39 ft)
Diameter: 1.32 m (4 ft 4 in) (1st stage)
Weight: 11,300 kg (25,000 lb)
Second stage: Hercules M57A1 solid rocket motor 156 kN (35,000 lbf)
Third stage: Aerojet General SR19-AJ-1 solid rocket motor 268 kN (60,300 lbf)
The Hercules M57A1 rocket motor is used for the second stage on the Hera, with a thrust of 15.6 kN. This is almost the same as the thrust of the TR-108. Therefore, it is likely that the TR-108 development program was implemented to replace the second stage of the Hera with a liquid rocket booster.
2. Northrop Grumman's First Pintle Injector Rocket Engine
The TR-108 was the first large pintle injector rocket engine developed after TRW's rocket engine development division was acquired and absorbed by Northrop Grumman.
Tom Mueller, who moved from TRW to SpaceX in 2002, had previously been involved in the development of the TR-106 and TR-107 rocket engines at TRW as a division manager and lead engineer. As you can see from the numbering, the TR-108 rocket engine was developed after Tom Mueller left TRW (now Northrop Grumman).
One of the differences between the TRW era and the TR-108 was the use of hydrogen peroxide as a green propellant, which had been used mainly for thrusters, to increase the size of the engine. In particular, the main catalytic bed for gasifying hydrogen peroxide was the largest one manufactured by General Kinetics, which was involved in the development as a subcontractor, and there were problems in terms of load on the bed and operating pressure.
On the other hand, Northrop Grumman, which acquired TRW, was the main developer of laser weapons for the U.S. military, and had experience with the airborne laser: YAL-1A, and the tactical high energy laser: MTHEL. In the development of the YAL-1A, the laser system was a chemical oxygen iodine laser (COIL), and the company had extensive experience in handling hydrogen peroxide as an oxidizing agent for the laser source, and this knowledge was utilized in the development of the TR-108.
3. Northrop Grumman TR-108 rocket engine
Thrust: 15.6 t (34,500 lbf)
Vacuum specific impulse: 271 s
Combustion Pressure: 6.2 MPa (900 psia)
Propellant: 91% hydrogen peroxide / toluene
Mixture ratio: 5.84
C* combustion efficiency: 93-94% (up to about 96%)
Nozzle ratio: 15.4
Maximum diameter: 2.6 ft
Length: 4.9 ft
Since it was developed as the upper stage of a targeted ballistic missile, it was designed in a shortened configuration to fit within the space of an existing aircraft. The layout of the piping and turbopumps was also designed to fit into the narrow space.
The TR-108 is a very simple system, with only a unit propellant to turn the turbine. Hydrogen peroxide is tapped from the oxidizer pump outlet and fed into the gas generator. Only one high-pressure valve in the path is needed to control it.
The requirement from MDA during the development of the TR-108 was to keep the recurring cost down. Cast turbopump housings, ablative combustion chambers, flight-qualified COTS hardware in other systems, and burst discs instead of high-pressure valves were used to minimize cost, schedule, and risk by using the maximum amount of robust technology, materials, and manufacturing methods proven since the TRW days.
Key development elements are following,
Main catalyst bed
Multiple pintle injectors for fuel
Ablative combustion chamber
Monopropellant turbo pump
The TR-108 was successfully tested at Northrop Grumman's Capistrano Proving Ground in San Clemente, California, where engine testing was conducted in a fully integrated configuration.
4. Multiple pintle injector
TR-108's Multiple Pintle Injector
The TR-108 rocket engine is equipped with a very unique "Multiple Pintle Injector". As shown in the photo above, a total of seven pintle injectors are arranged on the propellant injection side, unlike the usual single pintle injectors.
The seven pintle injectors are arranged in a hexagonal shape with one pintle injector at the center. This provides a more uniform mixing ratio and 102 fuel film cooling holes to provide film cooling. The mesh visible at the back is the main catalyst bed, which gasifies 91% of the hydrogen peroxide.
If the size of the propellant is too large to be supplied by a single pintle injector, or if it is deemed difficult to achieve sufficient capacity with a single pintle injector, multiple pintle injectors with multiple pintle injectors may be employed. (In the published literature, TR-108 is used. (Other than the TR-108, there is no other multiple pintle injector rocket engine at the practical use level in the published literature.
In particular, the TR-108 is considered to have adopted multiple pintle injectors because the propellant is not liquid-liquid, but liquid-gas, and therefore a single pintle injector was not considered to achieve the target performance. The uniform arrangement of multiple pintle injectors allows the fuel jets to increase their penetration distance and also allows for film cooling by the fuel.
In the TR-108, the pintle injectors were also designed to be easily replaced in order to change the fuel injection characteristics. In fact, in a short period of time, 13 different pintle injector configurations were tested. Looking at the tip of the pintle, there are two holes, and it is believed that a jig is inserted into this area to tighten the pintle tip section. The difference in the metal color suggests that it is manufactured with an alloy with good heat transfer properties.
The TR-108 was the first multiple pintle injector rocket engine developed by Northrop Grumman, but it is not known whether such a pintle injector had been developed at TRW before. However, it was difficult to develop a new type of injector for the TR-108, and in order to reduce the cost, "the robust technology, materials and manufacturing methods proven in the TRW era were used to the maximum extent. It is reasonable to assume that the multiple pintle injector technology had been developed since the TRW era.
To support the TR-108 program, a model was created to predict the combustion performance of this liquid-gas pintle injector, which uses hydrogen peroxide to jet liquid hydrocarbon fuel into a catalytically vaporized gas. In other words, the injector of the TR-108 is a liquid-gas mixture.
The correlation of the penetration distance of the liquid jet in the gas cross flow is important for the model to predict the combustion performance. It is important to know how much of the fuel jet injected radially by the pintle injector can spray and penetrate the oxidizer cross flow before reaching the combustion chamber wall. Such problems are complex in nature and are still the subject of active research.
Most experiments use air cross-flows to simulate gases, and water cross-flows to simulate jets, and analyze the results of the interaction. Therefore, the studies ignore the effects of factors such as rocket engine combustion and different fluid properties (viscosity, surface tension). Due to the uncertainty of this pre-simulation, a significant number of combustion tests were required for the multiple pintle injector in the development of the TR-108. However, as mentioned earlier, due to the inherent flexibility and simplicity of the pintle injector design, 13 different pintle configurations were tested in a relatively short period of time. A correlation model was built from the tests.
In the end, the TR-108 demonstrated a stable C* combustion efficiency of 93-94%. (A further 1-2% performance improvement is expected with fine tuning of the injectors.)
In the next article, we will discuss the pintle injector of SpaceX's Merlin rocket engine in light of the TR-108. (To be continued)
