Research on Advanced Solid Rocket Launcher

Vol. 43 No. 1 2010

OHTSUKA Hirohito : General Manager, Rocket Systems Department, IHI Aerospace Co., Ltd. YAGI Kazuhiro : Manager, Rocket Systems Department, IHI Aerospace Co., Ltd. KISHI Kohichi : Manager, Rocket Systems Department, IHI Aerospace Co., Ltd. NOHARA Masaru : Manager, Rocket Systems Department, IHI Aerospace Co., Ltd. SANO Naruhisa : Manager, Rocket Systems Department, IHI Aerospace Co., Ltd.

JAXA has started the research on the Advanced Solid fuel Rocket Launcher ( ASRL ). IHI Aerospace has been selected as the system integration company of the ASRL development. The ASRL is a successor to the M-V rocket, which has the top performance of the solid rocket launcher in the world. Moreover, the operational performance and cost reduction are targeted mainly in the ASRL development. Small satellites for space science or worldwatch technology demonstration are planned by JAXA and USEF. The ASRL is designed to be best for the small satellite users who have various special demands. The paper describes the summary of general ideas and the development plan of ASRL.

1. Introduction now developing VEGA rocket. Both of these rockets are strategically priced under Official Development Assistance IHI Aerospace Co., Ltd. (hereinafter called IA) has continued (ODA). It is essential that we see a change in attitude from to engage in research and development into solid fuel rocket one valuing performance, to one valuing operability and launchers ever since they first developed pencil rockets. IA costs. has also supported the development of M-V rockets, a type Small satellites are more cost-effective than large ones, of rocket which uses solid fuels for all stages and was used to and there will be demand for small satellites of 1 000 kg launch a planetary probe called “HAYABUSA” (which means or less in the future.(1) In particular, small satellites are “falcon” in Japanese), thus contributing to the advancement of expected to contribute to solving global issues such solid rocket launcher system technologies (Fig. 1). as global warming, because they provide a low-cost The M-V rockets achieved the world’s highest level of demonstration of sensor technologies for observation and performance, but their high costs meant that they were data collection on a global scale. Japan has developed two discontinued after the launch of a solar observation satellite small-satellite programs: one called Small Satellites for called “HINODE” (which means “sunrise” in Japanese) Space Science, where a single function will be observed so in September 2006. Solid rockets are highly regarded as to get results in short cycles; and the other called Small throughout the world for the small satellites launcher, Satellites for Technical Demonstrations to establish earth and the United States is now employing a type of solid observation technologies (Fig. 2). rocket called Minotaur, while European countries are Countries in Southeast Asia and other rising nations of space technology have a tendency to use their own small satellites to promote national land conservation, L (Lambda) rockets M-3S Pencil rockets M-V the advancement of science, and the fostering of human Launch of Japan’s (2) first satellite resources within each country, and these countries require

K (Kappa) rockets

Atmosphere and (a) Telescope satellite for planetary (b) Earth survey satellite

space observation observation SPRINT-A, approx. 300 kg ASNARO, approx. 450 kg

Launch of a fully-fledged Launch of a space science fully-fledged satellite planetary probe

1950 1960 1970 1980 1990 2000 ©ISAS ©JAXA ©USEF Fig. 1 History of Japanese solid rockets Fig. 2 Japan’s small satellite programs

29 Vol. 43 No. 1 2010 the support of advanced nations of space technology. To Launch system (improved operability, responsiveness, and mobility) respond to the current circumstances both here in Japan - Autonomous on-board and ground equipment and overseas, it is important that we quickly develop new (autonomous inspection) business models through cooperation among governments, - Operational labor saving - Compact, mobile ground equipment satellite manufacturers, and rocket manufacturers. Small satellites users have some unique requests, such as Comfort of mechanical environment unique launch operations, unique orbit, late access etc, and (user-friendly environment) - Separation mechanism with low shock there is a great deal of demand for single launches by the - Vibration control mechanism unique requests. The characteristics and functions of the - Technical innovation of acoustic pressure estimation

Advanced Solid fuel Rocket Launcher (ASRL) are well Fairing (environmentally-friendly structure) suited to such special and varied launch demands. - Designed to submerge in the sea, eliminating the need for recovery work 2. Targets for and design of the ASRL(3) Third-stage motor (KM-V3) The Japan Aerospace Exploration Agency (JAXA) began - Higher performance (light-weight motor case) research into the development of the ASRL in order to - Less costly case and propellant succeed and raise the M-V rocket system technologies and Second-stage motor (M-35) meet the launch demand for small satellites. IA has been - Higher performance (light-weight motor case) - Less costly case and propellant engaged in developing the concept of the ASRL since this research began, aiming to realize a low-cost small-satellite First-stage motor (SRB-A) (use of highly reliable technology) launch system with world-class operability and mobility. Avionics (demonstration of common technologies of the future) The authors have focused the specific key technologies - Modularization and networking in order to share technologies and components for the Response to diversified needs of users principal rocket. - Post-boost stage for high-precision and wide range of final orbits Figure 3 shows an illustration of the ASRL, Fig. 4 shows its key technologies, and Fig. 5 shows the target number of working days for ASRL launch sites around the world. Fig. 4 Key technologies in ASRL development

3. Overview of airframe Working days at launch sites (excluding day of launch)

3.1 Overall configuration and performance data ASRL (target) 15 The basic configuration of the ASRL will be a three- M-V 59 stage solid rocket, with a single-propellant post-boost Pegasus XL 98 stage (PBS) available as an optional fourth stage. Table 1 Athena2 18 describes the main characteristics of the ASRL, and Fig. 6 Taurus 20 Minotaur 15 Minotaur IV 15 Vega 26 Dnepr 29 Rockot 27

Fig. 5 Targets of working days at launch sites throughout the world

shows the configuration of the ASRL equipped with the optional PBS. The fi rst stage will use the SRB-A, a solid rocket booster that is used for H-IIA rockets. The second stage and the fairing will have an outer diameter of 2.1 meters, which is smaller than the standard size used for small satellites, to provide improved controllability during first-stage flight and to reduce costs. This three-stage configuration has been adopted to facilitate the insertion of satellites into the wide variety of orbits requested by satellite users, such as low-earth orbits (LEO), sun-synchronous orbits (SSO), and elliptical orbits. The distribution of propellant weight between the second ©JAXA and third stages will be optimized to enable a satellite to be Fig. 3 Illustration of the new ASRL inserted into any such orbit.

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Table 1 Main characteristics of ASRL processes that will be involved in order to achieve both Item Data cost reductions and greater performance, aiming to realize Total length Approx. 25 m a motor case that offers the highest level of structural 2.5 m (First stage) effi ciency in the world. Diameter 2.1 m (Second stage) Figure 7 shows a comparison of the performances of Weight when fully equipped*1 Approx. 91 t upper-stage launchers around the world. Solid three-stage configuration (5) Stage configuration 3.2.2 Rocket propulsion system (+PBS) - Low-earth orbit : 1.2 t The fi rst stage of the ASRL will be equipped with a highly- Orbit insertion performance - Sun-synchronous transfer orbit reliable SRB-A motor that was originally developed (Basic configuration) : 0.6 t for the H-IIA rocket. For the upper-stage motor, a high- - Elliptical orbit : 0.3 t performance propellant that was originally developed for Motor SRB-A the M-V rocket will be used. The design of the propellant Propellant Polybutadiene composite grain shape and the estimation of propulsion performance First TVC (deflection angle 5 degrees) Attitude control stage + SMSJ are based on the design policy behind the M-V rocket. The Weight when second stage will be equipped with a newly developed M35 Approx. 75 t fully equipped motor, which is almost the same size as the M34b motor Motor M-35 used in the third stage of M-V rockets. A high-performance Propellant Polybutadiene composite motor will be required for the third stage of the ASRL Second TVC (deflection angle 1 degrees) Attitude control because it will greatly affect the launch capability. stage + RCS Weight when Therefore, the KM-V3 motor mounted in the third stage Approx. 13 t fully equipped*2 will have the same head-end grain shape as that of the KM- Motor KM-V3 V2 motor, which was originally developed for M-V rockets, Propellant Polybutadiene composite to improve the structural efficiency. The authors have Third stage Attitude control Spin stabilization chosen to use ignition from behind to achieve a reduction Weight when in weight, and will employ a toroidal igniter that compactly *1 Approx. 3 t fully equipped contains a circular primer around the nozzle. This type of Propellant Hydrazine (single propellant) PBS igniter is the same as that used for the apogee boost motor Attitude control PBS thruster (3-axis) (ABM) for H-I rockets. Guidance control Inertial guidance (Note) *1 : Includes PBS but no satellite *2 : Includes fairing (to be discarded) of 0.6 t Target 0.94 0.93 0.92 0.91 3.2 Overview of airframe 0.90 0.89 (4)

3.2.1 Rocket Structure Mass ratio 0.88 For the first stage structure, the authors decided to use 0.87 0.86 a simple aluminum monocoque structure with a view to 0.85 reducing the cost of the first stage. For the upper stage, however, the authors focused on performance due to the VEGAVEGA B3 B2 PEGASUSPEGASUS B2 B3TAURUSTAURUS B2 B3 low impact on upper stage cost. They therefore decided to Modified M-35 ATHENA II B3 M-25M-34b (M-V (M-VB2) B3) M-35 (ASR B2) use light-weight materials such as fi ber-reinforced plastic KM-V1KM-V2 (M-V (M-VB4)KM-V3 B4) (ASRModified B3) KM-V3 (FRP). The authors also streamlined the manufacturing Fig. 7 Upper stage mass ratios for launchers around the world

Third-stage structure Joint between second Second-stage TVC Second-stage First-stage First-stage First-stage First-stage TVC Payload fairing for onboard equipment and third stages (movable nozzle) RCS structure for system tunnel SMSJ (movable nozzle) (option) onboard equipment

Storage area for satellite of 100 to 700 kg (option)

PBS (option) Third-stage Second-stage Second-stage Second-stage Second-stage Joint between first First-stage First-stage Thermal solid motor external tube structure for solid motor system tunnel and second stages solid motor rear tube curtain structure for onboard equipment (already developed onboard equipment SRB-A) Fig. 6 Configuration of ASRL

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3.2.3 Electric system(6) with two-way valves that allowed injections from two A lot of time and labor go into conducting inspections directions and required eight controllers. The authors and maintenance for rocket electric systems. The authors will equip the ASRL with a three-way valve that plan to develop advanced health monitoring, autonomous requires only two controllers, thereby reducing costs. inspection, and autonomous troubleshooting functions for Figure 8 shows an illustration of the new SMSJ. equipment used on-board the ASRL. They also plan to (3) Third-stage attitude stabilization dramatically improve operability so as to reduce the amount Instead of using TVC units, the authors will of time required before a launch. With an eye to the future, adopt a spin stabilization method to provide attitude the authors will expedite the development of high-speed stabilization for the third stage in order to achieve networking (by using space wires, for example) to facilitate cost and weight reductions. When equipped with the communication of various types of information for more optional PBS, the ASRL will be fitted with a Rhumb- advanced autonomous functions and flexible changes in line controller to reduce orbit errors before the final avionics configurations. The authors will also introduce stage. This will enable a reduction in the amount of the concept of modularization for technologies common to PBS fuel that is required for the final stage. principal rockets in order to reduce development costs and (4) Post-boost stage (PBS) attitude control prevent electric parts shortages by using common circuit The authors will design the ASRL to allow the boards. As small solid rockets have a relatively higher option of using a liquid fuel PBS for ASRL’s fourth avionics weight, size, and cost ratio than large principal stage in order to improve its orbit insertion accuracy to rockets do, it does not make sense at present to manufacture the same level as that of liquid rockets. It will also be components for small solid rockets that can be shared possible to use the PBS acceleration thruster for pitch/ with principal rockets. For this reason, the authors plan yaw attitude control, enabling the number of thrusters to promote the modularization of on-board computers, to be reduced. The authors will realize a low-cost, network interface boards, and other functions, as this will highly-reliable PBS by using the thrusters already enable components manufactured for small solid rockets employed by the reaction control system (RCS) and to be used with principal rockets as well. The authors will other devices used for the existing principal rockets. also optimize and integrate distributed functions in order to 3.3 Autonomous inspection system(7) reduce the number of components, thereby reducing costs. The authors plan to realize autonomous rocket inspections, By taking these measures, the authors aim to realize small, dramatically improving the efficiency and reliability of inexpensive, light-weight avionics that are suitable for small inspections and maintenance, both of which require a solid rockets. large number of engineers and a lot of time at present. 3.2.4 Control system The authors will also introduce databases for inspections, (1) Attitude control for the first and second stages maintenance, and troubleshooting, all of which are The authors will use the movable nozzle thrust completely reliant on human involvement at present, to vector control (TVC) method, which became a well- reduce the amount of time and labor required for these established method in the development of past solid activities. The authors also plan to develop a device that rockets, to provide attitude control for the first and will be able to inspect ignition circuits in a matter of second stages. They will also use electric servo hours instead of the several days it currently takes as it actuators, which are small and have proven to be is dangerous work. This device will be made compact highly operable. The authors plan to equip the first enough to be mounted on-board, reducing the amount of stage with the electric servo actuators that were equipment mounted outside the airframe and enabling safe originally developed for the SRB-A, while they will autonomous inspections to be conducted remotely (Fig. 9). equip the second stage with the small motorized actuators that is a partly modified version of the one used for the third stage of M-V rockets. (2) First-stage roll control and three-axis control For first-stage roll control and three-axis control,

the authors will develop a new controller that is On-off control valve equipped with a solid gas generator similar to the with the 3 valves solid motor side jet (SMSJ) used in M-V rockets. The SMSJ that uses a solid gas generator is superior to liquid gas jets as it can be stored for a long time without maintenance. It also has excellent starting

performance, enabling it to demonstrate the required Solid gas generator performance level as soon as it is started. As the SMSJ generates a large impulse for such a compact body, it is used to control the first stage, which requires a relatively high impulse. M-V rockets were equipped Fig. 8 New SMSJ

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Next-generation launch system - Networking of on-board equipment (space wire) Higher functionality (intelligence) ↓ Command terminal - Reduction (simplification) of burdens on equipment and operations On-board equipment control Emergency action wire command terminal

On-board autonomous inspection Control monitor function Subsystem status wire Ignition circuit inspection monitoring terminal On-board equipment inspection Monitor Subsystem status terminals Advancement of monitoring terminal space-to-ground communications Power supply equipment

©JAXA Electric charge and discharge wire

Automatic inspection functions Work result Automatic command execution Control and judgment according to work procedure command Work Automatic result preparation Work result report log database Work progress/ Work result display command Automatic Measurement data Data preparation chart Measurement Display data monitor Measurement result Operator Measurement data log database Automatic Airframe information collection Measurement preparation Measurement Dump list (continuous monitoring of data data airframe information) (paper and electronic data) Airframe controller

Autonomous inspection functions

Dynamic analog data Dynamic analog data evaluation program evaluation result Group of Measurement data Measurement normal data for evaluation data monitor - Normal data acquired by other rockets Display

- Normal data acquired by the same Dynamic analog data Work result Work progress/ rocket during factory operation and evaluation database result display Technical launch site operation support staff, etc. Judgment data Monitor terminal

Failure identification and Failure identification and troubleshooting procedure troubleshooting procedure extraction program

Analysis (Note) : Database FTA/ result Failure identification and FMEA troubleshooting procedure extraction database : Application

: User interface (screen display) Server

Fig. 9 Intelligent launch operation control system

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3.4 Innovative operation plan Simplified cage (1) Measures to improve operability (responsiveness)(8) Reducing the amount of work involved in launch- site operations is the key to being able to respond Simplified launch site facility more quickly to user needs (to ensure that satellites are always launched at the right time). The authors will adopt the following measures to reduce the amount of time required for launch-site operations, setting the standard for the rest of the world. ©JAXA Unitize components to reduce assembly time. Fig. 11 Mobile launch pad with a compact cage Discontinue the operations refueling RCS tanks at ①the launch site, adopting instead cartridge-type liquid ②RCS tanks so that the tanks can be filled with fuel at a to future generations, thus improving the efficiency of factory, transported to the launch site, and then quickly future rocket development (Fig. 12). attached to the rocket. (2) Mission analysis information system Develop the launch control system that is compact It takes more than one year from receipt of a request and mobile in order to realize automated and from a satellite user to launch a satellite. To provide ③autonomous functions for launch-site operation many launch opportunities at the right time, the launch management, on-board equipment inspection and cycle time need to be further reduced and significantly troubleshooting, and launch sequence managements reductions need to be made in mission analysis. To by utilizing the information databases. This will enable this end, the authors will create a database of results control operations to be handled by just a few operators from mission analyses conducted for several typical (Fig. 10). satellites that are to be launched, and compare the data (2) Mobile launching pads concept(9) with similar analysis results to reduce the analysis In addition to the above-mentioned on-board time (Figs. 12 and 13). autonomous inspection function and the mobile and 4. Future concept compact control system, the authors will develop a movable, simplified launch pad to realize the concept The ASRL will be able to launch microsatellites owned of mobile launch pads that will allow the ASRL to by universities and venture companies promoted by be launched anytime, anywhere. The rocket will be the government. It will provide such users with greater assembled using construction cranes. A simplified opportunities to launch their satellites, and broaden the cage will be used instead of a conventional large-scale availability of space utilization (Fig. 14). operation building to realize a simplified facility that Based on the results of their development of the ASRL, can be moved anywhere (Fig. 11). the authors would like to further improve the operability 3.5 Advanced information system for rocket and mobility of small high-efficiency solid rockets that will development(10) be developed in the future (Fig. 15). (1) Development process management system 5. Conclusion The authors will accumulate enormous technical documents and design know-how acquired in the The purposes behind the development of the ASRL are course of developing the ASRL in the form of a to meet the demand for small satellites used for space database that will enable technologies to be passed on science, global environment monitoring, and other fields contributing to the future of mankind, as well as to maintain and further develop solid rocket technologies. The only Japanese manufacturer to have solid rocket system technologies, IA was selected in 2009 as a system manufacturer for the development of the ASRL. Having assumed a great responsibility for the maintenance and advancement of solid rocket technologies, the authors would like to contribute to Japan and the rest of the world through their development of the ASRL and the launching and operation of small satellites. REFERENCES (1) FAA : 2009 Commercial Space Transportation

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Technical database management system

Function sharing and merging

Rocket development process management system Mission analysis information system Specification database Design database Analysis tool Grounds for System specifications determining Basic design Detailed design integration system Specified values … specifications - Automation Design study document A - Integration, etc. Document providing the basis for specified values Subsystem specifications Analysis result Two-way Subsystem specifications Reflection link Specification system Specified values … of result database comparison Specified values Design study System design control … system document B information (compliance - Correlation matrix for design, FMEA, Design study retrieval Component development - Statistics, etc. FTA, airframe configuration, Component development document C specificationsComponent development and system baseline control specifications specifications Reflection Design study documents) Specified values … Mission Specified values … of result Specified values … document D requirements

Evaluation and and satellite data and storage and Comparison Comparison

judgment

Evaluation Database method and Test result database plan Data Database Satellite/rocket data mission analysis result

Fig. 12 Intelligent information system for rocket development

Months required before launch 12 11 10 9 8 7 6 5 4 3 2 1 0 Single satellite of 100 to 1 200 kg Satellites such as H-IIA Mission request Satellite data Current piggy back satellites launch and satellite data update Final Launch Basic design Detailed design check Satellites (50 kg) of 100 kg Quick -response Mission request Satellite data launch and satellite data update Launch Satellites of several tens of Targets for ASRL Basic design Detailed Final kilograms design check Reducing mission analysis time by using Quick mission analysis information system Mission request -response launch and satellite data Launch Future final target Comparison

Fig. 13 Reduction of mission analysis time Fig. 14 Launch configurations for microsatellites

M-V

ASRL Enhanced global Next-generation competitiveness solid rocket - Simplified operation - Reduction in avionics size and weight - Autonomous inspection - Higher efficiency motors - Mobile control system - Light-weight structure - Higher-accuracy orbit - New launch pads insertion 135 tons when 90 tons when 45 tons when fully equipped fully equipped fully equipped SSO 750 kg SSO 450 kg SSO 400 kg Improved flexibility Air-launch vehicles (Notes) SSO : Sun-synchronous orbit - Air launch Take next leap forward for LEO : Low-earth orbit next-generation solid rockets (no restrictions on launch point) and air-launch rockets based - Autonomous flight 15 tons when fully equipped on the ASRL. - Utilization of upper-stage motors (modularization) LEO 100 to 200 kg

Fig. 15 Road map for small solid rockets

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(3) T. Imoto et al. : The development Plan for the (7) M. Tamura et al. : Development Plan of Advanced Solid Rocket Proceedings of 53rd Autonomous Checkout System for Advanced Solid Space Sciences and Technology Conference Rocket Proceedings of 53rd Space Sciences and JSASS-2009-4019 (2009) Technology Conference JSASS-2009-4023 (2009) (4) K. Ui et al. : The Development Plan for the Structure (8) S. Arakawa et al. : An Innovative Launch Operation Subsystem of the Advanced Solid Rocket Proceedings Concept of the Advanced Solid Rocket Proceedings of 53rd Space Sciences and Technology Conference of 53rd Space Sciences and Technology Conference JSASS-2009-4021 (2009) JSASS-2009-4025 (2009) (5) H. Habu et al. : The Development of the Solid (9) T. Kubota et al. : An Space Launch Complex Propulsion System for the Advanced Solid Rocket Project of the Advanced Solid Rocket Proceedings Proceedings of 53rd Space Sciences and Technology of 53rd Space Sciences and Technology Conference Conference JSASS-2009-4021 (2009) JSASS-2009-4024 (2009) (6) T. Inoue et al. : The Development Plan of Avionics (10) T. Tamura, H. Ohtsuka et al. : Intelligent Mission System for Advanced Solid Rocket Proceedings Analysis System Concept for Responsive Advanced of 53rd Space Sciences and Technology Conference Solid Rocket ISTS 2008 JSASS-2009-4022 (2009)