ECSS-E-ST-35-06属于机械学科的推进领域，并且关注推进部件，子系统和系统的清洁度 标准 •定义了允许清洁推进组件子系统和系统的设计要求，并避免产生或不必要的污染物的收集， •识别清洁度要求（例如可以容忍哪种颗粒/杂质/湿度水平）， •定义清洁要求，以符合清洁度要求，以及验证要求， •确定清洁度方法，清洁要求（例如需要做什么以确保不超过可容忍的水平，兼容性要求）， •识别，指定和定义有关进行清洁或清洁度验证的条件的要求（例如，兼容性，环境测试后检查）。 该标准适用于最常用的推进系统及其相关的可储存推进剂组合:肼（N2H4），单甲基肼（CH3N2H3），MON（氮的混合氧化物），氮（N2），氦（He），丙烷C3H8），丁烷（C4H10）和氙（Xe）。 该标准是欧洲航天器和航天器推进器的基础

ECSS-E-ST-35-06 belongs to the Propulsion field of the mechanical discipline, and concerns itself with the cleanliness of propulsion components, sub-systems and systems The standard • defines design requirements which allow for cleaning of propulsion components sub-systems and systems and which avoid generation or unwanted collection of contamination, • identifies cleanliness requirements (e.g. which particle / impurity / wetness level can be tolerated), • defines requirements on cleaning to comply with the cleanliness level requirements, and the requirements on verification, • identifies the cleanliness approach, cleaning requirements, (e.g. what needs to be done to ensure the tolerable level is not exceeded, compatibility requirements), • identifies, specifies and defines the requirements regarding conditions under which cleaning or cleanliness verification takes place (e.g. compatibility, check after environmental test). The standard is applicable to the most commonly used propulsion systems and their related storable propellant combinations: Hydrazine (N2H4), Mono Methyl Hydrazine (CH3N2H3), MON (Mixed Oxides of Nitrogen), Nitrogen (N2), Helium (He), Propane (C3H8), Butane (C4H10) and Xenon (Xe). This standard is the basis for the European spacecraft and spacecraft propulsion industry to define, achieve and verify the required cleanliness levels in spacecraft propulsion systems. This standard is particularly applicable to spacecraft propulsion as used for satellites and (manned) spacecraft and any of such projects including its ground support equipment. External cleanliness requirements, e.g. outside of tanks, piping and aspects such as fungus and outgassing are covered by ECSS-Q-ST-70-01. This standard may be tailored for the specific characteristic and constraints of a space project in conformance with ECSS-S-ST-00.