AIR FORCE - SMC-S-025
Evaluation and Test Requirements for Liquid Rocket Engines
|Publication Date:||26 July 2017|
This Standard establishes the test and evaluation requirements for liquid propellant rocket engines. These requirements shall be used to define a test program, primarily for qualification and production acceptance, that will appropriately verify the design, identify latent defects, ensure adequate functional performance, and help ensure a high level of confidence in achieving successful launch missions. It is expected that the overall program will also include a thorough development program and use other good engineering practices to help maximize the success of the test program.
This document is intended for compliance in government acquisition programs when levied by the Performance Work Statement (PWS), Statement of Work (SOW), and/or contract, and are intended to be flowed, as applicable, throughout the supply chain. The test requirements herein focus on design verification, and the identification of latent defects to help ensure a high level of confidence in achieving successful space missions. Unless otherwise specified by the Procurement Authority, the requirements herein are intended to apply to new or modified liquid rocket engine (LRE) designs, new or modified LRE unit designs, use in a new application or environment, and procurement from new supplier or a new manufacturing location. This Standard applies to LREs and associated propulsion systems for expendable and re‐usable applications. It is expected that as reusable engine technologies evolve over time, adjustments to the Standard may be needed. No distinction is made between non-human-rated and human‐rated systems. Relevant LREs include those using pump‐fed or pressure‐fed designs, with various propellant combinations including hydrogen/oxygen, hydrocarbon/oxygen, storable, or mono‐propellants. This Standard addresses development, qualification, acceptance, and pre‐launch testing for main propulsion systems (i.e., steady‐state, non‐pulsing, thrust greater than 4,500 N (1,000 lbf)) for space launch vehicles (including booster, upper stage, and in‐space propulsion). This Standard focuses on testing of an LRE at the individual engine and integrated propulsion system levels, but includes lower level testing where warranted
The engine system as a whole is generally defined to encompass those components from the engine inlet flanges to the thrust chamber nozzle, and includes all interface connections to the launch vehicle and launch facility.
This Standard is intended to be used with other mission assurance documents, including SMC-S-016  and SMC-S-005 . Within the nomenclature of SMC-S-016 , an LRE is categorized as a subsystem. An engine system, which may include multiple LREs, and the entire launch vehicle propulsion system are also considered subsystems within the SMC-S-016  nomenclature. Within the nomenclature of SMC-S- 005 , an LRE is categorized as a pressurized system, meaning there are pressure-containing elements within the LRE. This Standard utilizes these documents and provides more detailed and specific requirements applicable to LREs and their integration. The terminology within this document is only intended to provide clarification of the appropriate requirements, and not to supersede the test category classifications of other mission assurance standards.
Within this Standard, all requirements are numbered and indicated by the word shall, thereby differentiating requirements text from explanatory or guidance text.