The X-1, the first manned sonic flight, and the X-15, a manned rocket plane capable of reaching outer space, were powered by Reaction Motors' XLR11 rocket engine, which is a cutaway model of the XLR11 rocket engine turbopump.
Reaction Motors XLR11 (some references refer to it as "XLR-11", but the official name does not require a dash) or LR11 was the rocket engine installed in the X-1, the first manned sonic flight, and the X-15, a manned rocket plane capable of reaching outer space. The X-15 was equipped with two XLR11s as a stopgap until the XLR99, the official rocket engine, could be installed.
It uses LOX/75% alcohol as propellant, and has four combustion chambers regenerated and cooled by alcohol. The thrust output is changed by operating and shutting down the combustion chambers individually. The propellant type and configuration are the same as those of the V-2 rocket.
The XLR11-RM-1 was nitrogen pressurized to operate the engine, XLR11-RM-3 was helium pressurized, and XLR-11-RM-5 was hydrogen pressurized. The XLR11-RM-5 on X-1 had a thrust of 26.67 kN, and propellant was supplied by a turbopump. The XLR11-RM-5 was also used as a booster for the Douglas Skyrocket, and was called the XLR8-RM-5 at that time.
XLR11 rocket engine installed on the X-15.
The turbopump exhaust pipe can be seen on the lower left of each rocket engine (left)
The XLR11 is designed with reliability in mind, as it is a rocket engine that will be installed in a human rocket aircraft. The propellant, LOX/alcohol, is not highly toxic and is relatively easy to handle; although the specific impulse is lower than that of LOX/kerosin, the XLR11 is a rocket engine with a regenerative cooling channel, which is an advantage in aircraft maintenance and operation, considering that it can be overhauled and reused without worrying about coking. The XLR11 is a rocket engine with regenerative cooling channels.
This may be the reason why kerosene was not used for reusable, regenerative cooling rocket engines for aircraft applications until the 1960s. The reason for the use of kerosene in the XLR99 rocket engine, which was later installed in the X-15, is that it was designed to be reused, and the advantage of no coking of the regenerative cooling channels and injectors was given priority.
XLR11 and XLR99 on the X-15
Cutaway model of regenerative cooled combustion chamber XLR11
In Japan, the XLR11 can be seen on display. The XLR11 used to be on display at the Transportation Museum in Osaka, but was transferred to the Shizuoka University of Science and Technology Aviation Museum when the museum closed in April 2014.
XLR11-RM-5 rocket engine transferred from Osaka Transportation Museum to Science to Shizuoka University of Science and Technology
2. Cutaway model of XLR11 rocket engine turbo pump
The XLR11 turbopump is difficult to visualize from the outside, but have obtained a photo of a rare cutaway model, which is described above.
XLR11 Rocket Engine Turbo Pump Specifications
Cycle: Gas Generation Cycle
Gas: Hydrogen Peroxide (90%)
Rotation Speed: 12240 rpm
Fuel Flow: 132 GPM (gallons per minute), 499.68 L/min
Naval Newsによると、ワシントンD.C.近くで開催された、Sea Air Space 2021において、ボーイングが、艦載戦闘機用の極超音速ミサイル：Hyfly2のコンセプト図を発表した。X-51A以降、ボーイングは、ロッキードマーチンとレイセオンに敗れていたが、Hyfly2で巻き返しを図る模様である。
1. Sea Air Space 2021で発表されたコンセプト図
Naval Newsによると、ワシントンD.C.近くで開催された、Sea Air Space 2021において、ボーイングが、艦載戦闘機用の極超音速ミサイル：Hyfly2のコンセプト図を発表した。
According to Naval News, at Sea Air Space 2021 held near Washington D.C., Boeing presented concept drawing of Hyfly2, a hypersonic missile for use carrier-based fighter aircraft. Boeing has been losing ground to Lockheed Martin and Raytheon since the X-51A, but with the Hyfly2, it seems to be trying to get back on track.
1. Conceptual drawing presented at Sea Air Space 2021
According to Naval News, at Sea Air Space 2021 held near Washington D.C., Boeing presented concept drawing of Hyfly2, a hypersonic missile for use carrier-based fighter aircraft.
Hyfly2 concept drawing
Boeing continues to design and invest in future hypersonic cruise missiles, and according to another article in Aviation Week, the U.S. Department of Defense has brought Boeing into the competition with its Mach 6 HyFly2 program, funding preliminary design reviews and ground testing of the DCR (Dual Combustion Ramjet).
In its R&D performance with Hyfly in the 2000s and X-51A in the early 2010s, Boeing was the leading U.S. company in the development of scramjet-powered missiles. However, since the mid-2010s, Boeing has been losing contracts and competition for U.S. military contracts to Lockheed Martin and Raytheon in the hypersonic missile field and for orders for scramjet-equipped missiles. Boeing seems to be trying to regain its footing with the Hyfly2.
2. Features of Hyfly2
The Hyfly2, like the Hyfly, is a Dual Combustion Ramjet (DCR), and a detailed description of the engines used in the Hyfly is given in a previous article below.
The Hyfly is a hybrid engine that combines a ramjet engine and a scramjet engine, a concept that was shown at APL in the 1970s. The Hyfly project was developed assuming a cruise speed of Mach 6, and the Hyfly2 project also assumes Mach 6, and is expected to be equipped with an improved version of the Hyfly. The Hyfly2 project also assumes Mach 6 and is expected to carry an improved version of Hyfly.
Comparison between Hyfly2 and Hyfly/X-51A
From the concept drawing, we can see the circular nozzle and the X-shaped steering wing inherited from Hyfly at the rear.
On the other hand, the inlet section is a single two-dimensional inlet, just like the X-51A. Also, like the X-51A, it has the characteristic of a web rider shape with a cut from the side of the inlet to increase lift under shock waves. From this, we can see that the concept is a combination of Hyfly and X-51A.
The Hyfly and X-51A have been tested for air launch in the 2000s and early 2010s, respectively; the X-51A achieved powered flight with a scramjet engine, but the Hyfly failed and the project was cancelled. This is just a guess, but it may mean that the X-51A's two-dimensional inlet system was superior to the X-51A's in order for the inlet to work properly, and the DCR was superior to the X-51A's combustion system for maintaining supersonic combustion.
In order to achieve DCR, the inlet for ramjet combustion and the inlet for scramjet combustion were separated and placed at the tip of the Hyfly. However, the concept drawing of Hyfly2 has only one inlet like the X-51A, and in order to achieve DCR combustion with this shape, it is expected that the inlet will be divided into two channels, one for ramjet and one for scramjet.
3. Aerojet Rocketdyne was acquired by Lockheed Martin
In the R&D program for the X-51A, Pratt & Whitney Rocketdyne (now Aerojet Rocketdyne) was in charge of developing the SJX61/SJY61 scramjet engine to be installed in the X-51A. (now Aerojet Rocketdyne) was responsible for the development of the SJX61/SJY61 scramjet engines to be installed in the X-51A.
SJX61/SJY61 Scramjet Engine
Aerojet and Rocketdyne, long-established manufacturers of rocket engines and missile propulsion systems from the early U.S. space program to the space shuttle, merged in 2013 to become Aerojet Rocketdyne. However, this one and only manufacturer was acquired by Lockheed Martin in December 2020. As a result, Boeing may not be able to use Aerojet Rocketdyne, a direct competitor under Lockheed Martin, as a vendor.
Aerojet Rocketdyne is also believed to be responsible for some of the engines for the large scramjet-powered aircraft that are under development, such as the SR-72. Although there are various US military programs to develop hypersonic missiles, Lockheed Martin has surpassed its competitors in the number of contracts and continues to lead the pack.
Space Oneのロケット内部構造等について推定した結果から、最終的にロケット全体の能力値を推定した表を以下に示す。推定の前提として、衛星質量を150kgとし、PBSを100kgとした。ここで、低軌道への打ち上げ能力は250kg、太陽同期軌道への打ち上げ能力は150kgと公開されているが、後者の想定で、PBS込みの重量とした。
なお、1.35mの固体ロケットモータは、M-3ロケットからも少し外れた外径となる。このクラスと同等の打ち上げロケットとしては、イスラエルが初の人工衛星を打ち上げた、「シャヴィト」（Shavit）から発展した、Shavit1 (LK-A)）がある。Shavit1は、固体3段式，質量 30000 kg，外径 1.35m, 全長17.2 m, LEO 225kgであり、Shavit1は、Shavitの増強型である。
This article estimates the launch capability of the solid-fuel rocket: KAIROS (Kii-based Advanced & Instant ROcket System), which Space One plans to launch from Kushimoto-cho, Wakayama Prefecture, based on external views and published data.
*Since this estimate was made in June 2020, the rocket diameter was estimated to be φ1.4m. Later information, φ1.35m, was revealed by a newspaper article in July 2021.
*This blog will write a new article or add more information later, Because of additional information.
Canon's SLR cameras are the best. Let's all buy one.
1．Space One's new solid-fuel rocket: KAIROS, whose appearance has been released.
Canon Electronics announced in 2018 that it has established SPACE ONE, a joint venture to promote the small rocket launch business. Space One, established by Canon Electronics, IHI Aerospace, Shimizu Corporation, and the Development Bank of Japan, aims to achieve the world's shortest contract-to-launch period and the world's highest launch frequency by providing a dedicated small launch vehicle and launch site, with the goal of commercialization in 2021.
The actual status of the rocket development has been shrouded in mystery so far, and it is believed that IHI Aerospace will be in charge of the propulsion system, but only the following information has been released as specifications.
The appearance of the rocket was included in a presentation given at a briefing session in Kushimoto Town, Wakayama Prefecture, in August 2019, but the images of the slides were not made available to the public via the Internet. However, at a presentation held at the Ministry of Education, Culture, Sports, Science and Technology on Wednesday, January 15, 2020
This article estimates the launch capacity of the Kairos rocket that Space One is planning to launch from Kushimoto-cho, Wakayama Prefecture, based on its external view and published data.
2．Space One KAIROS Rocket Structure Understanding and Structure Estimation
External view of Space One's KAIROS rocket, released via the Ministry of Education, Culture, Sports, Science and Technology
To estimate the structure of the launch vehicle, we estimated the interior of the launch vehicle from the information on the dimensions of the satellite payload in the public "Launch Vehicle Overview" and the official website.
2-1．Dimensions of the satellite payload space
Payload space dimensions from Space One official website and
and the image with the correct scale and aspect ratio
First, we grasped the dimensions of the satellite payload space. We used the "Space One Official Website Payload Launch Capability Document" posted on the official Space One website as a reference. The dimensions, scale, and aspect ratio of the payload space in this document were wrong when I measured them, so I corrected them as shown in the figure above.
The image on the right is from the official website, and the image on the left is from the author's corrected image with the correct scale ratio. I don't know if it is intentional or just a matter of randomness that the dimensions in the external documents are wrong. In fact, as long as the dimensions are given, there is no problem, but as a satellite launch company, I think it would be better to make sure that the documents are in line with the actual situation.
2-2．Estimation of Space One KAIROS rocket structure dimensions
Assuming that the published data was correct, we traced the images to get an idea of the external and internal dimensions of the rocket.
To begin with, there is only one picture of the aircraft that has been released to the public, and the accuracy of the details is unknown. In addition, the published specifications are sketchy: the weight is "about" 23 tons, and the total length is 18 meters.
The outline drawing of the rocket is a CG outline drawing, and the observation point of view seems to be the view of the rocket body from the center side. (If you look closely, you can see that the nozzles and fairings are angled.) Therefore, it is not an accurate representation of the side projection of the vehicle, and the further away from the center, the larger the error becomes. The further away from the center, the larger the error. Therefore, please understand in advance that what I am going to describe is a rough estimation to some extent.
From the outline drawing, I assumed the size of the rocket to be just 18 meters in length, which is the size disclosed by Space One. The figures are probably rounded off, so there is an error of about 18m → 18m ± 0.5m. On top of that, I estimated the structure as follows, taking into account the CG intervals and other factors.
It should be a 3-stage + PBS (post-boost stage) configuration with a diameter of about 1.4 meters.
In July 2021, it was announced in a newspaper article that it would be 1.35m in diameter, and this estimation seems to have been largely correct.
Estimated KAIROS rocket structure dimensions
Size and structure comparison with M-V No. 4 and Enhanced Epsilon launch vehicle
3．The diameter of the rocket is about 1.4 meters, and it follows the know-how of the M-3 rocket?
The rocket diameter of Space One, estimated from the outline drawing, is about Φ1.35 to Φ1.4m, even taking into account the error. Here, we estimated the rocket diameter to be Φ1.4m.
This diameter is the same size of rocket motor diameter as the M-3 rocket with a diameter of Φ1.41m, which used to be operated by the Institute of Space and Astronautical Science (ISAS). If this estimate is correct, it means that Space One's rocket can use the previous manufacturing facility design and development know-how of the former Nissan Motor (now IHI Aerospace).
To compare the scale of the rockets, a comparison of the size of the M-3H rocket and the Space One rocket is shown in the figure below.
Comparison of M-3H rocket and Space One KAIROS rocket
Space One is a company established with investment from Canon Electronics and IHI Aerospace, but since solid fuel rocket technology is used for the propulsion system, it is not a rocket development from scratch. The technology of the current IHI Aerospace, which has supported ISAS space rocket development for many years since the days of the former Nissan Motor, is being used.
It is unclear whether the manufacturing facilities for the M-3 rocket, which has the same diameter, are still available or can be used. However, rather than adopting a completely new diameter rocket motor, it is a very rational choice to set the same diameter as that of the M-3 rocket, because it is possible to use some of the past rocket motor manufacturing technology and development know-how.
By using the same diameter, they can use the existing design of the grain manufacturing equipment, even if it is not a metal rocket motor of the same diameter. Test jigs and other equipment that have been used in the past can also be used.
The representative diameter is 1.35m, which is a new development. This is the same diameter as Israel's Shavit and China's Land space's ZhuQue-1 (ZQ-1, LandSpace-1, LS-1), which will be discussed later.
4．Same diameter as M-3S rocket, half the weight, half the launch capability
Payload weight ratio comparison between Space One and other rockets (low orbit)
The table above is a comparison of the payload weight ratio between Space One's launch vehicle and other launch vehicles (low orbit). In addition to solid-fuel rockets, liquid-fuel rockets are also shown on the right for reference.
Due to the structural weight and specific impulse, liquid-fueled rockets are basically more advantageous in terms of payload weight ratio per rocket weight. Also, the larger the rocket, the more advantageous the payload weight ratio.
I was not able to find a solid-fuel rocket that has already been put to practical use with an equivalent scale of 150 kg payload, but the M-3S rocket that was once operated by ISAS can be used as a reference. The manufacturer of the rocket is IHI Aerospace (formerly Nissan Motor), the same as the manufacturer of Space One's KAIROS rocket.
◆M-3S rocket
Launch capability: 300 kg (low orbit)
Length: 23.8 m
Diameter: Φ1.41 m
Weight: 48.7 t
As mentioned earlier, the diameter of Space One's rocket is about the same as that of the M-3 rocket (Φ1.4m), and interestingly, it is exactly half the weight of the M-3S rocket (48.7t → 23t), and has exactly half the launch capacity (0.3t → 0.15t).
5．CFRP rocket motors or metal rocket motors?
It is not possible to determine whether the Space One rocket uses a metal rocket motor or a CFRP rocket motor. The following options may be considered.
・Manufacture with all CFRP rocket motors.
・To reduce the cost, only the first stage is made with metal rocket motors, and the second and third stages are made with CFRP rocket motors.
If we want to achieve high performance, we should use CFRP rocket motors for all stages, but if we want to reduce the manufacturing cost, metal rocket motors are cheaper, so we can choose to use metal rocket motors for the first stage only to reduce the cost and focus on the upper stage. There is a possibility that a hybrid configuration is used as a trade-off.
6．Estimated performance of the Space One KAIROS rocket
The following table shows the final estimates of the overall capability of the rocket based on the results of estimating the internal structure of the Space One rocket and other factors.As an assumption for the estimation, the satellite mass was assumed to be 150 kg and PBS was assumed to be 100 kg. Here, the launch capability to low earth orbit and sun-synchronous orbit are disclosed as 250 kg and 150 kg, respectively, but we assumed the latter and assumed the weight including PBS.
*This estimate is current as of June 2020 and should be revised based on new public information.
Estimated performance of the Space One KAIROS rocket
(assuming a diameter of 1.4 m)
7．Basis for Estimating Rocket Launch Capacity
The following is the basis for the estimation.
◆Satellite: 150 kg → Public Information
◆PBS section: 100 kg (N2O/ethanol, Isp 300 sec)
The mass of PBS is estimated to be about 50 to 100 kg, but here we estimated it to be 100 kg. The propellant mass ratio was set to 0.33, or 1/3, because PBS is equipped with communication equipment, avionics, and gas push tanks.
The propellant was estimated to be "N2O/ethanol". This was stated during the public opening of the JAXA Noshiro Rocket Testing Center in 2017, "Canon Electronics will conduct a ground burn test starting next week. The propellant is N2O/ethanol," an explanatory staff member is reported to have said. In fact, ISAS and IHI Aerospace have collaborated in the past to conduct experimental research on N2O/ethanol propulsion system for PBS. Based on this information, the specific impulse was estimated to be 300 seconds based on the paper, assuming that the PBS, the fourth stage, is an N2O/ethanol propulsion system.
N2O/ethanol propulsion system jointly researched by ISAS and IHI Aerospace
*This estimate is current as of June 2020 and should be revised based on new public information. New information suggests that PBS is likely to be a monopropellant system.
◆Fairing section: 112kg
The weight of the fairing is based on that of the M-V. It is made of CFRP and aluminum honeycomb structure. The Space One rocket is estimated to have a fairing diameter of 1.5 m in diameter and 4 m in length, so the scale ratio was estimated by the following calculations.
((2.5/2)^2)*9=((1.5/2)^2)*4 X, X=0.16, 700X = 112 kg
◆Interstage section (2nd stage to 3rd stage)：30kg
Since the structure is considered to be lightened by CFRP, we estimated the weight to be 30 kg including the separation mechanism.
◆Avionics section and separation mechanism: 30kg
The avionics part is estimated to weigh 30 kg, including the separation mechanism, because Canon Electronics has applied its consumer technology cultivated through the manufacture of camera parts.
8．Additional Information
This estimate was made in June 2020, but the following information came out later.
Private Company Successfully Conducts Combustion Test in Noshiro to Develop Small Rockets
On the 30th, a solid motor combustion test was conducted at the Noshiro Rocket Testing Center of the Japan Aerospace Exploration Agency (JAXA) in Asanai, Noshiro City, Akita Prefecture, with the aim of launching a small rocket by the end of this fiscal year. The test was a success. Space One is a private company funded by Shimizu Corporation, Canon Electronics, and others. It is the first private company to apply the solid rocket technology developed by JAXA.
Solid Motor Combustion Test at Noshiro Test Center to Develop New Generation Small Rockets
On the 30th, a vacuum ground firing test of the third stage solid motor of the "New Generation Small Launch Vehicle," a small satellite launch vehicle being developed by Space One (headquartered in Tokyo) for launch this fiscal year, was held at the JAXA (Japan Aerospace Exploration Agency) Noshiro Rocket Testing Center in Asanai, Noshiro City. The test was conducted jointly by JAXA's Institute of Space and Astronautical Science (ISAS), and the test was completed without any trouble. The test was conducted in cooperation with JAXA's Institute of Space and Astronautical Science (ISAS), and the test was completed without any trouble. There were no problems with the motor, and the data obtained will be utilized for launch. The new-generation small rocket, which is being developed by the company, is a three-stage rocket with a total length of 18 meters, a typical diameter of 1.35 meters, and a total mass of about 23 tons, to which a liquid stage has been added to improve orbit injection accuracy. It is capable of injecting a 150 kg small satellite into a sun-synchronous orbit. This is the first time that Japan's solid rocket system technology, which has been developed since the Pencil Rocket, has been applied to a commercial project. The combustion test was conducted jointly by the company and the Institute in order to share the results of the latest solid motor technology and contribute to the maintenance and development of solid motor technology and testing technology in Japan. The full-scale motor (1.8 meters in length, 1.35 meters in diameter, and 9 tons in maximum thrust) was used to verify the combustion propulsion characteristics, the TVC function to change the direction of thrust and control the attitude by moving the nozzle with an actuator, and the measurement system. It has been five and a half years since the second stage motor of the enhanced Epsilon rocket was developed. About 70 people from the company and the institute participated in the test and prepared for the test. The work went smoothly, and with favorable conditions such as wind speed and direction, the motor was ignited at around 10 a.m. Flames and white smoke billowed out from the test building where the motor was installed, and a roaring sound echoed. According to Shinichiro Tokudome, associate professor at the institute and the chief of the experiment, the combustion time was about 70 seconds and the thrust was just under 9 metric tons, almost as planned. According to Shinichiro Tokudome, associate professor at the institute and head of the experiment, the test was almost on schedule, with a burn time of about 70 seconds and a thrust of just under 9 tons. He said that detailed test results would not be known until they are verified, but the test was a success, as good data was obtained, including normal operation of the TVC function. For ignition, a laser ignition system, which is not affected by static electricity or electromagnetic waves and which is a result of the institute's research, was used instead of an electric detonator, and it functioned properly. The data obtained will be analyzed and shared between the company and the institute. Associate Professor Tokudome said, "The spirit of challenge of the private sector is important for the market development of rockets, and JAXA will contribute to this by transferring the technology it has cultivated to companies, and will support the promotion of industry. In the future, JAXA plans to test the first-stage solid motor of a new-generation small rocket at the same test site.
The following information has been newly determined.
Representative diameter of 1.35m 【assumed in capacity estimation → slightly larger estimate of φ1.4m】
Conducted combustion test of 3rd stage rocket motor with TVC, burn time about 70 seconds, maximum thrust about 9 tons, laser ignition system used for ignition
As of July 2021, the first stage solid motor has not yet been tested.
Based on the scaling of thrust and burn time, the third stage estimated it have may propellant error of a few hundred kg.
The 1.35-meter solid rocket motor has an outer diameter that is slightly outside the M-3 rocket. An equivalent launch vehicle in this class is the Shavit1 (LK-A), which evolved from the Shavit, Israel's first satellite launch vehicle. the Shavit1 is a three-stage solid rocket with a mass of 30000 kg, an outer diameter of 1.35 m, a length of 17.2 m, and LEO 225 kg.
Shavit 1 is an augmented version of Shavit. Shavit1 is an enhanced version of Shavit. Shavit was a three-stage rocket with all solid fuel stages, and the first and second stages were based on the "Jericho 2" semi-medium range ballistic missile, and a spherical rocket motor manufactured by Rafael Advanced Defense Systems was added to the third stage of the missile to achieve satellite launch.
Israel's Shavit, with a diameter of 1.35 meters
Another rocket with a diameter of 1.35 m is the ZhuQue-1 (ZQ-1, LandSpace-1, LS-1), a three-stage solid rocket with a diameter of 1.35 m, developed by Land Space, a Chinese space venture, which was successfully launched in October 2018. ZhuQue-1 is slightly larger than the Kairos rocket, with all three stages 1.35 m in diameter, 19 m in length, 300 kg LEO, and 200 kg SSO. It has been pointed out that ZhuQue-1 may have been developed based on the rocket motor of the Dongfeng 26 (DF-26) medium-range ballistic missile, as well as Israel's Shavit.
ZhuQue-1, Shavit, KAIROSの比較
In addition, JAXA announced that IHI Aerospace has lent a jig to Space One. It is unclear what the jig means, but it is presumed to be a jig related to the manufacture of solid rocket motors.
"IHI Aerospace's dedicated tools for H-IIA, Epsilon, and H3 rockets were loaned to Space One Corporation for the purpose of "development and manufacturing operations of launch vehicles for nano-satellite launches."
