SIST EN 16603-35-03:2014

Space engineering - Liquid propulsion for launchers

General requirements applying to all type of Propulsion Systems Engineering are defined in ECSS-E-ST-35. For Liquid propulsion for launchers activities within a space project the standards ECSS-E-ST-35 and ECSS-E-ST-35-03 are applied together.
This Standard defines the specific regulatory aspects that apply to the elements and processes of liquid propulsion for launch vehicles. It specifies the activities to be performed in the engineering of these propulsion systems and their applicability. It defines the requirements for the engineering aspects such as functional, physical, environmental, quality factors, operational and verification.
Other forms of propulsion (e.g. nuclear, nuclear-electric, solar-thermal and hybrid propulsion) are not presently covered in this issue of the Standard.
This standard may be tailored for the specific characteristic and constrains of a space project in conformance with ECSS-S-ST-00.

Raumfahrttechnik - Flüssigantriebe für Trägerraketen

Ingénierie spatiale - Propulsion liquide pour lanceurs

Vesoljska tehnika - Tekoča pogonska goriva za lansirnike

Splošne zahteve, ki veljajo za vse vrste inženiringa pogonskih sistemov, so opredeljene v standardu ECSS-E-ST-35. Za dejavnosti, povezane s tekočimi pogonskimi gorivi v okviru vesoljskega projekta, skupaj veljata standarda ECSS-E-ST-35 in ECSS-E-ST-35-02. Ta standard opredeljuje posebne regulatorne vidike, ki se nanašajo na elemente in postopke za tekoča pogonska goriva za lansirnike. Določa dejavnosti, ki se izvajajo v tehničnem delu teh pogonskih sistemov in njihovo uporabnost. Določa zahteve za inženirske vidike, kot so funkcionalni, fizikalni, okoljski, kakovostni dejavniki, zahteve med delovanjem in verifikacijo. Druge oblike pogonov (npr. jedrski, jedrsko-električni, solarno-termalni in hibridni pogon) trenutno niso zajeti v tej izdaji standarda. Ta standard se lahko prilagodi posameznim lastnostim in omejitvam vesoljskega projekta v skladu s standardom ECSS-S-ST-00.

General Information

• Status: Published
• Publication Date: 22-Oct-2014
• ICS: 49.140 - Space systems and operations
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 22-Sep-2014
• Due Date: 27-Nov-2014
• Completion Date: 23-Oct-2014
• Mandate: M/496 - Mandate addressed to CEN, CENELEC and ETSI to develop standardisation regarding space industry (Phase 3 of the process)
• Ref Project: EN 16603-35-03:2014 - Space engineering - Liquid propulsion for launchers

Overview

EN 16603-35-03:2014 (CEN) - "Space engineering - Liquid propulsion for launchers" defines the engineering requirements specific to liquid-propellant propulsion systems used on launch vehicles. Intended to be applied together with the general propulsion requirements in ECSS-E-ST-35, this standard governs the regulatory, design, development, verification and in‑service aspects of liquid propulsion elements and processes for launchers. It may be tailored to project constraints in conformance with ECSS-S-ST-00.

Key topics and requirements

• Scope and applicability: Covers liquid propulsion for launch vehicles; excludes nuclear, nuclear‑electric, solar‑thermal and hybrid propulsion in this issue.
• Functional requirements: Thrust, specific impulse (Isp), burn time, throttling profile, mixture‑ratio management, restart capability, thrust vector control (TVC) performance and health monitoring.
• Constraints: Mechanical (acceleration, geometry), electrical continuity, safety and ground/flight safety considerations.
• Development process: System requirements, concept trade‑offs, preliminary and detailed design, qualification, production, and first‑article reviews. Includes modelling, validation and a verification plan per ECSS-E-ST-10-02.
• Detailed design areas: Propellant tanks and management, filling/draining systems, feed/pump systems, thrust chamber assembly (TCA), gas generator/pre‑burner, turbomachinery, TVC, control & monitoring, and auxiliary systems (e.g., roll control, anti‑POGO).
• Verification & testing: Requirements for analyses, component/subsystem/engine tests, qualification and acceptance procedures; emphasis on updating and validating mathematical models with test data.
• Support topics: Ground support equipment (GSE), materials and cleanliness, production/manufacturing, in‑service operations (filling, chill‑down, launch chronology, passivation) and deliverables.

Practical applications and users

• Who uses it: Launcher system integrators, propulsion engineers, system architects, qualification/test teams, suppliers of liquid engines, tanks, turbomachinery and feed components, and certification/QA organisations.
• Why use it: To define acceptable engineering practices, ensure compatibility with ECSS system standards, support requirement traceability and verification, and reduce technical and programmatic risk for liquid‑propulsion stages.
• Typical projects: Development or procurement of first/upper stages for orbital launch vehicles, design of cryogenic or storable liquid propulsion systems, qualification of engines and feed subsystems, and preparation of technical specifications and verification plans.

Related standards

• ECSS-E-ST-35 (Propulsion general requirements) - normative companion.
• ECSS-E-ST-10-06 (Technical requirements specification), ECSS-E-ST-10-02 (Verification plan) and other ECSS documents referenced for system engineering, materials and structural design.

Keywords: EN 16603-35-03:2014, liquid propulsion, launchers, space engineering, ECSS-E-ST-35, propulsion system design, verification, thrust chamber, propellant tanks, turbomachinery.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Raumfahrttechnik - Flüssigantriebe für TrägerraketenIngénierie spatiale - Propulsion liquide pour lanceursSpace engineering - Liquid propulsion for launchers49.140Vesoljski sistemi in operacijeSpace systems and operationsICS:Ta slovenski standard je istoveten z:EN 16603-35-03:2014SIST EN 16603-35-03:2014en,fr,de01-november-2014SIST EN 16603-35-03:2014SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16603-35-03
September 2014 ICS 49.140
English version
Space engineering - Liquid propulsion for launchers
Ingénierie spatiale - Propulsion liquide pour lanceurs
Raumfahrttechnik - Flüssigantriebe für Trägerraketen This European Standard was approved by CEN on 23 February 2014.
CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN and CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved worldwide for CEN national Members and for CENELEC Members. Ref. No. EN 16603-35-03:2014 E SIST EN 16603-35-03:2014

This standard forms parts of ECSS-E-ST-35 series which has the following structure; • ECSS-E-ST-35 Propulsion general requirements • ECSS-E-ST-35-01
Liquid and electric propulsion for spacecrafts • ECSS-E-ST-35-02 Solid propulsion for spacecrafts and launchers • ECSS-E-ST-35-03 Liquid propulsion for launchers • ECSS-E-ST-35-06 Cleanliness requirements for spacecraft propulsion components, subsystems, and systems • ECSS-E-ST-35-10 Compatibility testing for liquid propulsion components, subsystems, and systems ECSS-E-ST-35 contains all the normative references, terms, definitions, abbreviated terms, symbols and DRD that are applicable for ECSS-E-ST-35, ECSS-E-ST-35-01, ECSS-E-ST-35-02 and ECSS-E-ST-35-03. In the use of this standard, the term ‘propulsion system’ is intended to be read and interpreted only and specifically for ‘liquid prolusion system’. SIST EN 16603-35-03:2014

EN reference Reference in text Title EN 16601-00-01 ECSS-S-ST-00-01 ECSS system - Glossary of terms
EN 16603-10 ECSS-E-ST-10 Space engineering - System engineering general requirements EN 16603-10-02 ECSS-E-ST-10-02 Space engineering - Verification EN 16603-10-06 ECSS-E-ST-10-06 Space engineering - Technical requirements specification EN 16603-32 ECSS-E-ST-32 Space engineering - Structural general requirements EN 16603-32-02 ECSS-E-ST-32-01 Space engineering - Fracture control EN 16603-32-02 ECSS-E-ST-32-02 Space engineering - Structural design and verification of pressurized hardware EN 16603-32-10 ECSS-E-ST-32-10 Space engineering - Structural factors of safety for spaceflight hardware EN 16603-35 ECSS-E-ST-35 Space engineering - Propulsion general requirements EN 16602-70 ECSS-Q-ST-70 Space product assurance - Materials, mechanical parts and processes
ISO 15389:2001 Space systems - Flight-to-ground umbilicals
Abbreviation Meaning LPS liquid propulsion system
• The liquid propulsion system generally consists in:  the engine  the tank  the feed system  the pressurisation system  the command system  the TVC  auxiliary systems such as the anti-POGO device, roll control system
• The typical life of a liquid propulsion system is the following:  Manufacturing and assembly  Acceptance test (if any)  Storage and transport  Launcher integration  Pre-launch activities (e.g. flushing, leak tightness checks)  Tanks filling  Main stage Chill down (for cryogenic liquid propulsion system)  Launch chronology (including launch-abort activities) SIST EN 16603-35-03:2014

The way how to write the technical specification is given in ECSS-E-ST-10-06. SIST EN 16603-35-03:2014

The additional functional requirements are: • thrust level versus time (throttling) • propellant budget management (e.g. mixture ratio variation) • TVC (e.g. maximum angle, acceleration, response time) • start-up and shutdown transient requirements (e.g. duration, impulse scatter) • auxiliary power to be delivered to the launcher (e.g. electrical and fluids) • re-startability • propellant depletion 5.2 Mission a. ECSS-E-ST-35 clause 4.2 shall apply. 5.3 Functions a. The technical specification shall provide the values of thrust, Isp and burning time with their deviations. SIST EN 16603-35-03:2014

The acceleration has an impact on the: • functioning of the vortex suppression devices in the tank outlets; • pressure at the pump inlets; • flow pattern in the tank; • mechanical loads. 6.2 Geometrical constraints a. The dimensioning of the liquid propulsion system and its components shall conform to the overall launch vehicle dimensions, interfaces between stages, ground infrastructure and requirements for transportation. 6.3 Electrical constraints a. The design of the prop system shall be such that the electrical continuity is ensured. 6.4 Safety a. The design of the liquid propulsion system shall conform to the safety requirements of the launch system. NOTE
For Example, ground safety requirements, flight safety requirements. SIST EN 16603-35-03:2014

Example of verification methods are analyses, tests. SIST EN 16603-35-03:2014

Preliminary design phase is Phase B of ECSS-M-ST-10. d. Mathematical models shall be updated using component and subsystem results at milestones agreed by the customer. e. Mathematical models shall be validated using test results. f. Mathematical models shall be used to determine the design margins. g. The development logic shall list the activities that are submitted to cross-check. NOTE
See ECSS-E-ST-35 clause 4.8.1. h. The sequence of development activities shall include components and subsystem tests prior to system tests. i. The development logic shall mention the difficulties and critical activities of the development. NOTE
In particular major development critical path. j. The development logic shall include risk management activities for project and technical risks. k. The development activities shall include verification that manufacturing and control processes lead to products that satisfy specified product-to-product variation limit. l. Lessons learned from previous programs shall be introduced in the design development plan. m. The critical technologies, manufacturing and control processes shall be listed and their qualification process described. NOTE
See ECSS-Q-ST-20. n. Liquid propulsion system verification shall be obtained by testing the liquid propulsion system in conditions representative of flight. NOTE
Following the typical approach “Test as you fly”. o. Through the measurement plan of the qualification flight the LPS qualification shall be checked by post flight analysis. p. The development test plan shall include limit testing and failure cases. q. At the end of the development, the testing of the integrated system in its final configuration, including the electrical system, shall include tests with representative interfaces. NOTE
For example, typical interfaces are control computer, electrical interface, flight instrumentation. SIST EN 16603-35-03:2014

For example, temperature, humidity, salt content of the atmosphere, inter stage conditioning). c. The loads induced by the liquid propulsion system acting on the launch vehicle and the payload shall be identified, evaluated and reported in the design definition file as defined in the ECSS-E-ST-10 Annex G DRD. NOTE
Examples of these loads are chugging, side loads, vibrations, blast wave, thermal radiation. d. Interface requirements shall be derived from the extreme operating envelope. SIST EN 16603-35-03:2014

Criteria are for example performance, reliability and development cost and recurring cost. b. The design resulting from the optimisation of the above criteria 9.1a shall be provided and justified. 9.2 Specification a. The specification of a liquid propulsion system or subsystem shall be in conformance with ECSS-E-ST-10-06. 9.3 Propulsion system selection 9.3.1 Overview The mixture ratio is derived from a system optimization analysis, taking into account the characteristics of the envisaged liquid propulsion system and rocket engines. The mixture ratio and the total amount of propellants, is the determining factor for the sizing of the tanks, together with the pressure and temperature. 9.3.2 System selection a. For the selection of the liquid propulsion system architecture, a trade-off analysis shall be performed using the following parameters: 1. type of propellants; 2. engine architecture and thermodynamic cycle; 3. propellant mixture ratio; 4. propellant storage; 5. pressurization and feed system; 6. any additional parameters specified by the customer. SIST EN 16603-35-03:2014

The filling subsystem can be combined with the draining functions. 9.4.3.2 Draining system in flight (passivation and degassing) a. In-flight draining shall not create conditions that can lead to loss of performance of the launch vehicle. b. If in-flight draining cannot be performed through the flow paths for the normal operation of the propulsion system, specific lines or valves shall be incorporated in the liquid propulsion system to enable in-flight draining. 9.4.3.3 Flushing, purging and venting a. The subsystems or components of the liquid propulsion system for which flushing, purging or venting is performed during ground tests, launch activities (including launch-abort) and flight, shall be identified. b. The liquid propulsion system shall provide valves and lines to flush, purge or vent the subsystems or components identified in 9.4.3.3a. c. On ground, the flushed and purged fluids shall be collected. d. The flushing and purging systems shall neither create hazards to personnel nor harm the environment. e. Provisions shall be taken to ensure that vented fluids do not create hazards. NOTE
For example, burn-off of vented hydrogen. f. Flushing, purging and venting in flight shall not create unwanted propulsive effects. NOTE
For example, non-propulsive venting. 9.4.4 Propellant tanks and management 9.4.4.1 General a. the tank volume shall be designed using at least the following: 1. The amount of propellant to be used during nominal propulsion operations; 2. the amount of propellant provisions covering the liquid propulsion system and launch vehicle deviations; 3. losses and ejected propellants; 4. the amount of unusable propellant; 5. the ullage volume; SIST EN 16603-35-03:2014

The most usual worst case is when the: • temperature of pressurant is minimum, • final volume of propellant tank is maximum, • pressure of propellant tank is maximum (based on pressure regulator characteristics). e. Pressurant gas budget shall include provision for gas leakage through equipment of the pressurisation system. f. For the initial design a 30 % margin shall be used on the pressurant mass. g. The pressurization system shall not induce pressure oscillations in the liquid propulsion system or stage. h. There shall not be back flow (gaseous or liquid) into the pressurization system. i. The pressurization system shall prevent detrimental contact between dissimilar fluids. SIST EN 16603-35-03:2014

The maximum design pressure (MDP) is defined in ECSS-E-ST-32, term 3.2.27 9.4.4.2.3 Minimum tank pressure a. The minimum tank operating pressure shall conform to with the tank structural requirement. b. The minimum tank operating pressure shall conform to with the engine inlet requirement. 9.4.4.3 Tank draining a. An emergency draining or depletion procedure shall be present in case the nominal draining operation fails. b. For all tanks, the location of fill-and-drain valves and the piping layout shall be such that liquids are not trapped in the system by on-ground draining and dissimilar fluids do not come into contact with each other. c. The tank design shall be such that the occurrence of a vortex is prevented. NOTE
This usually happens when the tank is nearly empty d. If 9.4.4.3c. is not met an anti-vortex device shall be installed at the sump to avoid gas ingestion into the feed lines. e. The acceptability of propellant depletion shall be integrated in the “development logic” clause 7.2. 9.4.4.4 Sloshing a. Propellant sloshing shall be analysed during all phases of the mission. b. The effects of propellant sloshing in tank shall be analysed at both launch vehicle and liquid propulsion system levels. NOTE 1 The propellant sloshing can have an effect on for example: • Guidance, navigation and control of the launch vehicle, • Propellant thermal stratification, • Tank pressurisation. NOTE 2 Anti sloshing device can be introduced to limit the sloshing amplitude. SIST EN 16603-35-03:2014

PMD device can be introduced to limit the above effects (such as swirl and sloshing). 9.4.4.6 Common bulkheads a. The management of the pressure of each tank shall demonstrate that, during the whole mission, the bulkhead does not fail. 9.4.4.7 Temperature management a. For storable propellants, the temperature prevision accuracy shall be 0,5 K. b. For cryogenic propellants, the temperature prevision accuracy shall be 0,1 K. c. If there is thermal stratification, the temperature distribution shall be evaluated with the same accuracy as respectively 9.4.4.7a for storable propellants and 9.4.4.7b for cryogenic propellant. d. A thermal balance shall be established for all phases of the mission. 9.4.5 Propellant feed system 9.4.5.1 General a. The feed system shall ensure a homogeneous parallel flow at the engine inlet in the thermodynamic conditions defined in the engine technical specification. 9.4.5.2 Pressure drop a. The pressure drops in the feed system shall be determined by calculations. NOTE
The calculation of the feed system pressure drop takes into account the characteristics of the components constituting the feed system. b. The LPS measurement plan shall allow the measurement of feed system pressure drop. c. The combination of the deviations and uncertainties shall be performed via a statistical approach. NOTE
Statistical approach can be quadratic combination or Monte Carlo. SIST EN 16603-35-03:2014

(Rapid) variations in the mass flow rate in the feed system can introduce pressure fluctuations. These are related to the time rate of change of the mass flow rate and to the geometry of the feed system (L, D). These pressure fluctuations can interact with the structure of the feed system or adversely affect motor operation, e.g. pump cavitation. c. Water-hammer phenomena shall have no detrimental effect on the structural and the functional behaviour of the propulsion system. d. Rapid decomposition of the propellant vapour shall be avoided. NOTE
This decomposition can be created by: • adiabatic compression, • contact with hot spots and catalyst materials. 9.4.5.3.2 Propulsion system dynamic interaction with launch vehicle structure (POGO) a. The POGO phenomenon shall be analysed for the whole mission. b. The result of the analysis in 9.4.5.3.2a shall be used to conclude regarding the need of an anti-POGO device. c. POGO Mathematical modelling shall be reported as defined in the ECSS-E-ST-35 Annex I DRD. 9.5 Liquid engines 9.5.1 General a. At engine system level, geometrical (CAD models), functional, mechanical, thermal models shall be established and used to derive subsystem specifications. b. Subsystem shall provide inputs to the above models at various steps of the development. c. The engine system shall allocate reliability objective for each subsystem. d. The test plan of the liquid engine shall include subsystem test objectives when establishing test plan and allocate instrumentation channels accordingly. SIST EN 16603-35-03:2014

This concerns: • the main nozzles, • the contribution from dump cooling, • the turbine exhaust gases, • ventings, purgings. 9.5.3 Functional system analysis 9.5.3.1 General a. Nominal engine performance and deviation shall be defined at a reference operating point. b. Engine performance losses shall be analysed and reported in the design justification file in as defined in ECSS-E-ST-10 Annex K DRD. c. Contributions to engine thrust shall be analysed and reported in the design justification file as defined in ECSS-E-ST-10 Annex K DRD. d. The operating limits of each major subsystem shall be reported at engine definition file level. NOTE
For example, maximum rotating speed corresponding to disk burst, flow separation limit, combustion chamber mixture ratio limit. 9.5.3.2 Performance a. The performances of the engine shall be determined and documented in the design justification file as defined in ECSS-E-ST-10 Annex K DRD. SIST EN 16603-35-03:2014

For liquid rocket engine, the performance concerns at least: • Thrust • Isp • Mixture ratio • Dry mass • Required NPSP • Roll moment • Fluid consumptions • Electrical consumptions 9.5.3.3 Reference point and envelopes 9.5.3.3.1 Overview For operational envelope see ECSS-E-ST-35 clause 4.5.3.1. For qualification points see ECSS-E-ST-35 clause 4.5.3.2. 9.5.3.3.2 Operational envelope a. In the initial design process, an operational envelope shall be selected in conformance to the stage or launch vehicle requirements. b. The liquid propulsion system or subsystem shall operate within the operational envelope specified in 9.5.3.3.2a. NOTE
During the design process, the launch vehicle or stage requirements can change; it is therefore prudent to consider a project margin when defining the operational envelope. c. The operational envelope shall be designed with the following parameters: 1. The range of functional parameters of the liquid propulsion system during flight and testing. NOTE
In particular flow rate, mixture ratio, tank propellant pressure. 2. The range of interface parameters. NOTE
In particular acceleration effect, inlet pressure and inlet temperature variations, temperature environment. 3. Deviations in the trimming and throttling of the propulsion system. 4. Deviations in the various modelling processes. 5. Deviations in component performances. 6. Deviations in manufacturing. 7. Deviations in measurements. SIST EN 16603-35-03:2014

This means that the qualification points are covering the operational envelope. b. The qualification points shall be defined using the following parameters: 1. ground test facility conditions compared to the flight ones; 2. deviations in the trimming and throttling of the propulsion system; 3. deviations in the modelling processes; 4. deviations in the component performances; 5. deviations in manufacturing; 6. deviations in measurements. c. If a rocket engine is expected to operate in disconnected envelopes (qualification envelopes which do not overlap) the following shall be performed: 1. the engine qualified in each envelope separately; 2. ensure that a transition between the two envelopes can be made; 3. the transient process specified in 9.5.3.3.3c.2. qualified. 9.5.3.3.4 Reference point a. One or more reference points shall be defined. b. The performance optimization point shall be required in the engine specification. 9.5.3.3.5 Extreme envelope a. An extreme envelope shall be defined around the qualification points using: 1. hardware deviation; 2. test bench deviation. b. The extreme envelope shall be reported from the PDR. SIST EN 16603-35-03:2014

In particular mixture ratio, pump rotational speed. b. A test bench configuration representative of the stage configuration and flight environment shall be used. c. If 9.5.3.4.3b. is not met, a justification shall be provided and cross checked. d. The supplier shall demonstrate that any dynamic effect, generated during start-up, is kept within the specified ranges for the stage and launch vehicle. e. For multi engine stage, criteria shall be defined for thrust profile deviations between engines. f. The start-up sequence shall include the following: 1. pressurization of the propellant tanks, 2. settling of the propellants in the tanks, 3. performance of the OBCs, 4. complete filling of lines, pumps and cooling circuits. g. If a liquid propulsion system is expected to be activated after a ballistic flight, a propellant settling analysis shall be carried out. 9.5.3.4.4 In-flight transients a. In flight transient between two operated conditions shall not create adverse dynamic effects. b. 9.5.3.4.4a. shall be verified by tests. 9.5.3.4.5 Shutdown a. The supplier shall demonstrate that the engine functional parameters during shut-down remain within the specified range. NOTE
Functional parameters such as mixture ratio and pump rotational speed. SIST EN 16603-35-03:2014

In addition, the thrust chamber can have the following secondary functions: • to enable the installation and functioning of transducers and measurement equipment; • to provide pressurized fluids to subsystems (e.g. tank pressurization and TVC).
The main components of the thrust chamber assembly are: • the injector, • the igniter, • the combustion chamber and • the nozzle.
...