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This specification replaces GJB 2787-1996 General specification for satellite propulsion system.
The following main technical changes have been made with respect to GJB 2787-1996:
a) the name is changed to Specification for propulsion system of spacecraft, and the application scope is extended from satellites to spacecrafts;
b) the related contents of electric propulsion system are added;
c) the related contents of components (units) except the system level in the former specification are deleted;
d) the system integration, foreign object debris control and thrust vector adjustment are added;
e) the annexes in the former specification are deleted;
f) Annex A giving the main indicator ranges of various propulsion systems is added;
g) Annex B giving the propulsion system types recommended according to the spacecraft mission characteristics is added.
Annexes A and B of this specification are informative.
This specification was proposed by the Equipment Department of Aerospace Systems Division, PLA Strategic Support Force.
GJB 2787 was issued for the first time in 1996.
Specification for propulsion system of spacecraft
1 Scope
This specification specifies the technical requirements, quality assurance requirements and delivery preparation for propulsion system of spacecraft (hereinafter referred to as propulsion system).
This specification is applicable to the design, production, test and acceptance of cold gas propulsion system, chemical propulsion system and electric propulsion system of spacecraft.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this specification. For dated reference, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this specification. However parties to agreements based on this specification are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references or references with version not indicated, the latest edition of the normative document referred to applies.
GB 190 Packing symbol of dangerous goods
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 678 Chemical reagent - Ethanol
GB/T 4844 Pure helium, high pure helium and ultra pure helium
GB/T 5828 Xenon
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 8979 Pure nitrogen and high purity nitrogen and ultra pure nitrogen
GJB 98 Anhydrous hydrazine
GJB 145 Specification of preservation packaging
GJB 150.15 Laboratory environmental test methods for military materiel - Part 15: Acceleration test
GJB 150.16 Laboratory environmental test methods for military materiel - Part 16: Vibration test
GJB 150.18 Laboratory environmental test methods for military materiel - Part 18: Shock test
GJB 151 Electromagnetic emission and susceptibility requirements for military equipments and subsystems
GJB 190 Classification of characteristics
GJB 294 Specification for fusion welding of aluminum and aluminum alloys
GJB 1027 Test requirements for launch, upper-stage, and space vehicles
GJB 1673 Specification for nitrogen tetroxide
GJB 1718 Electron beam welding
GJB 1963 Specification for methylhydrazine
GJB 1964 Specification for green nitrogen tetroxide
GJB 2203 Cleanliness and contamination control requirements for satellite product
GJB 2502.2 Test method for thermal control coatings of spacecraft - Part 2: Measurement of solar absorptance
GJB 2502.3 Test method for thermal control coatings of spacecraft - Part 3: Measurement of emissivity
GJB 2770-1996 Storage environmental condition for military material
GJB 2998 Mark of satellite products
GJB 4014 Gaseous helium safe application rules
GJB 5403 Anhydrous hydrazine safe application rules
GJB/Z 35-1993 Derating criteria for electrical, electronic and electromechanical parts
QJ 1408 Reliability assurance requirements for aerospace products
QJ 1666 Technical requirements for fusion welding of titanium and titanium alloy
QJ 1842 Technical requirements of structural steel and stainless steel fusion welding
QJ 2053 Satellite leak detection test method
QJ 2437 Analysis of effect and criticality of satellite failure
QJ 2630.1 Space environment test methods for spacecraft units - Part 1: Thermal vacuum test
QJ 2850 Prevention and control for foreign object debris (FOD) of space products
QJ 2865 Technical requirements for welding tube
QJ 3198-2008 Safe technique requirement for pyrotechnic devices used on apace vehicles
3 Requirements
3.1 Composition
Generally, the propulsion system consists of functional modules such as propellant storage module, propellant filling (discharging) module, propellant supply module, thruster (motor) module, system parameter (pressure, temperature, flow rate, etc.) detection module and propulsion line module. When necessary, functional modules such as high-pressure gas storage module, decompression control module, power supply processing module and thrust vector adjustment module may be configured.
3.2 Functions
The propulsion system mainly provides the forces and torques necessary for spacecrafts.
3.3 Working medium
3.3.1 Propellant
3.3.1.1 Cold gas propulsion system
Generally, nitrogen is selected as propellant. The physical and chemical properties of nitrogen shall meet the requirements of GB/T 8979. Other propellants include ammonia and butane.
3.3.1.2 Chemical propulsion system
3.3.1.2.1 Single-component propulsion system
Generally, anhydrous hydrazine is selected as propellant. Anhydrous hydrazine shall meet the requirements of monopropellant in GJB 5403 or GJB 98. Other propellants include ammonium dinitramide (ADN), hydroxylamine nitrate (HAN), DT-3, etc.
3.3.1.2.2 Double-component propulsion system
Generally, green nitrogen tetroxide (or nitrogen tetroxide) and methylhydrazine are selected as propellants. The green nitrogen tetroxide shall meet the requirements of Grade A in GJB 1964, the nitrogen tetroxide shall meet the requirements of GJB 1673, and the methylhydrazine shall meet the requirements of GJB 1963. Other propellants include nitrogen tetroxide and anhydrous hydrazine.
3.3.1.3 Electric propulsion system
Generally, xenon or anhydrous hydrazine is selected as propellant. The xenon shall meet the technical indicator of Grade I pure xenon in GB/T 5828, and the anhydrous hydrazine shall meet the requirements of monopropellant in GJB 98.
3.3.2 Pressurized gas
Generally, helium or high purity nitrogen is selected as pressurized gas. The helium shall meet the requirements of GJB 4014 and the high purity nitrogen shall meet the requirements of GB/T 8979.
3.4 Performance
3.4.1 Total impulse
The propulsion system shall be able to provide a total impulse sufficient for the spacecraft mission.
3.4.2 Carrying volume of propellant
The carrying volume of propellant shall meet the total impulse demand, and the following factors shall be considered:
a) propellant required for thruster (motor) start-up and test;
b) propellant leaking normally during its lifetime;
c) propellant unavailable in tanks, gas cylinders and pipelines at the end of lifetime.
3.4.3 Working points
The requirements for working points of propulsion system are as follows:
a) the design of working pressure shall ensure that the inlet pressure of thruster (motor) is within its design working pressure range;
b) the design of working temperature shall meet the design working range of thruster (motor), and the minimum working temperature of liquid propulsion system shall be at least 5℃ higher than the freezing point of propellant;
c) the propellant flow rate, working voltage and working current of the electric propulsion system shall meet the requirements of the design working range of the electric thruster.
3.4.4 Flow characteristics
The flow characteristics of propulsion system include flow rate, pressure drop, mixing ratio, etc. The flow rate-pressure drop characteristics of components (units) and the flow characteristics of pipeline for propulsion system shall be matched with the working point design of the propulsion system.
3.4.5 Sealing performance
3.4.5.1 Leakage rate of propulsion system
The leakage rate of propulsion system is related to the scale and in-orbit lifetime, and the leakage rate indicator shall meet the requirements of special technical documents.
3.4.5.2 Single point leakage rate
Generally, when helium is adopted as leakage indication gas, the single point leakage rate under the maximum expected working pressure is as follows:
a) not greater than 1×10-6Pa·m3/s at the thread connection;
b) not greater than 1×10-7Pa·m3/s at the welding connection.
3.4.6 Performance of thruster (motor)
The main performance parameters of thruster (motor) are shown in Table 1, and the value of each parameter shall meet the requirements of special technical documents.
Table 1 Main performance parameters of thruster (motor)
S.N. Main performance parameter Application scope
1 Vacuum thrust All thrusters (motors)
2 Vacuum thrust range Variable-thrust thruster (motor)
3 Vacuum specific impulse All thrusters (motors)
4 Mixing ratio Double-component thruster (motor)
5 Minimum impulse Thruster (motor) working in pulse mode
6 Steady-state lifetime All thrusters (motors)
7 Pulse life Thruster (motor) working in pulse mode
8 Thrust vector All thrusters (motors)
9 Startup response time and shutdown response time Thruster (motor) with required impulse output response time
10 Residual impulse Thruster (motor) with required speed increment control
11 Plume divergence angle Thruster (motor) with required plume control
12 Thruster efficiency Electric thruster
3.4.7 Power supply conversion efficiency
The power supply conversion efficiency of the power supply conversion module of electric propulsion system shall not be less than 88%.
3.5 Weight
The weight of propulsion system (excluding propellant and pressurized gas) shall meet the requirements of special technical documents. See Annex A for the weight of various propulsion systems.
3.6 Power consumption
The power consumption of propulsion system shall meet the requirements of special technical documents. See Annex A for the power consumption of various propulsion systems.
3.7 Marks
The product marks shall meet the requirements of GJB 2998. The code and number of product on the product mark shall be consistent with the marks of product certificate and product quality log.
3.8 Appearance
The appearance shall meet the following requirements:
a) the surfaces of metal products shall be free from burrs, scratches, bumps, rust spots and cracks, and the surface plating shall be flat, smooth, and free from peeling and falling off;
b) the non-metallic surfaces shall be smooth, flat, free from peeling, flaking, delamination and cracking as well as defects affecting use such as precipitation of additives;
c) the pins and sockets of electric connectors shall be in good shape, with bright surface plating, no shedding, no rust spots and burrs, and the surface of glass insulators shall be smooth, free of pores and impurities; the insulators shall be firmly combined with pins and shells, without cracks at the joint, and the air tightness shall meet the requirements of special technical documents;
d) the sealing surfaces of various components (units) and pipeline joints shall be free from scratches, the threads shall be clean and intact, the locking shall be firm, the lead seal shall be correct and complete, and the weld surface shall meet the requirements of GJB 294, GJB 1718, QJ 1666, QJ 1842 and QJ 2865.
3.9 Materials and electrical, electronic and electromechanical parts
3.9.1 Selection principles
The selection principles of materials, electrical and electronic and electromechanical parts are as follows:
a) select materials and electrical, electronic and electromechanical parts that meet the requirements of working performance, service environment, storage period, lifetime and manufacturing process from the selection catalogue as possible, and use them after passing the re-inspection according to requirements, and screen the electrical, electronic and electromechanical parts according to the requirements of special technical documents;
b) the adoption of new materials and electrical, electronic and electromechanical parts shall be fully demonstrated, tested, identified or finalized, and pass the type approval.
3.9.2 Materials
The materials shall meet the following requirements:
a) compatibility: the metallic and nonmetallic materials shall be of Grade I compatible with the working medium in direct contact during the lifetime, otherwise they shall be used after passing the review. The parts shall be corrosion resistant. The protective measures, which shall be remained effective throughout the lifetime, shall be taken on the surfaces of non-corrosion-resistant materials;
b) no hairline: the metallic materials of important components (units) (such as injector of thruster, valve body and element of gas and liquid valves) shall be hairline-free materials;
c) anti-aging: the performance of non-metallic materials shall meet the service requirements during the lifetime.
3.9.3 Electrical, electronic and electromechanical parts
The electrical, electronic and electromechanical parts shall be derated for use, and their derating shall meet the requirements of Grade I in GJB/Z 35-1993; otherwise, they shall be used after passing the review.
3.10 System integration
The requirements for propulsion system integration are as follows:
a) the layout and polarity of propulsion system pipeline shall meet the design principle requirements of propulsion system, and effective process control shall be carried out;
b) issues such as control force, control torque, plume and thermal effect shall be considered for the layout of thruster (motor);
c) for components (units) with large calorific value, the heat dissipation mode shall be considered when designing contact area and layout position, and the requirements of thermal control shall be met;
d) dowel pins or adjustment mechanisms may be adopted for components (units) to be accurately installed in place. When the calibration accuracy is superior to 0.15°, it is necessary to set a calibration reference (usually an optical reflector) on the components (units);
e) the pipeline system shall be connected by welding as possible, and the components to be replaced or subjected to special requirements may be connected by screwing;
f) the welding quality of pipeline shall meet the requirements of QJ 2865, and the quality of welded joint shall be of Grade I;
g) the set points of pipeline welds shall be easy for X-ray photography, and meet the requirements of bidirectional orthogonal X-ray photography, otherwise they shall be indicated during the design and approved by the parties concerned;
h) generally, the bending radius of the pipeline is not less than four times the outer diameter of the pipeline, otherwise, it shall be implemented after process appraisal and review;
i) generally, the distance between pipelines is not less than 6mm, and the distance between pipeline and other instruments/equipment/structural parts is not less than 10mm; for pipelines requiring thermal control, the space for thermal control coating shall be reserved;
j) generally, lubricants are not used for all moving components (units) of the propulsion system;
k) sealing grease shall not be used as an auxiliary sealing measure at sealing parts, and sealing materials and products shall meet the requirements of compatibility and lifetime.
Foreword i
1 Scope
2 Normative references
3 Requirements
3.1 Composition
3.2 Functions
3.3 Working medium
3.4 Performance
3.5 Weight
3.6 Power consumption
3.7 Marks
3.8 Appearance
3.9 Materials and electrical, electronic and electromechanical parts
3.10 System integration
3.11 Interfaces
3.12 Environmental adaptability
3.13 Electromagnetic compatibility
3.14 Reliability
3.15 Safety
3.16 Foreign object debris (FOD) control
3.17 Thrust vector adjustment
4 Quality assurance requirements
4.1 Inspection classification
4.2 Inspection conditions
4.3 Appraisal inspection
4.4 Acceptance inspection
4.5 Packaging inspection
4.6 Inspection method
5 Delivery preparation
5.1 Sealing
5.2 Packaging
5.3 Transportation
5.4 Storage
5.5 Marks
6 Instructions
6.1 Intended use
6.2 Classification
6.3 Contents required to be specified in the order document
6.4 Others
Annex A (Informative) Main parameters of propulsion system
Annex B (Informative) Recommended application range of propulsion system
