BS EN 16603‑33‑11:2019 pdf download.Space engineering – Explosive subsystems and devices.
4.1 General 4.1.1 Overview Being generally applicable, the requirements stated in this clause apply throughout and are not repeated in the clauses relating to specific topics. Explosive subsystem and devices use energetic materials (explosives, propellants, powder) initiated by mechanical, electrical, thermal, or optical stimuli, for unique (single shot) functions e.g. solid booster initiation, structure cutting, stage distancing, pressurized venting, stage neutralisation, valve opening or closing, release of solar arrays, antennas, booms, covers and instruments. The properties of the initiator govern the major part of the behaviour of the subsystem. The requirements for initiators and their derivatives, such as cartridges and detonators, are defined in specific requirements related to the specific types. Properties of explosive components and subsystem, which cannot be covered by requirements for the initiators alone, are defined in specific requirements relating to the types of explosively actuated device or pyromechanisms.
4.2 Design 4.2.1 General a. In case of redundancy, no component shall adversely affect its substitute. b. The system lay-out should facilitate the replacement of subsystems or components. c. Parts of the explosive subsystem and devices identified as critical on the basis of a RAMS analysis shall be replaceable. d. Replaceable parts shall be listed in the User’s Manual of the explosive subsystem and devices. 4.2.2 Reliability and confidence a. The explosive subsystem shall achieve the specified properties within the required reliability and confidence level defined at system level. b. The reliability demonstration shall be: . 1. used to justify design margins including the influence of ageing, temperature and explosive batch, 2. justified according to clause 6.4.2 of ECSS-Q-ST-30 or dedicated system specification, and 3. stated in a reliability prediction document as per Annex E of ECSS-Q-ST- 30. NOTE Dedicated system specifications are, for example, GDIR and SG.
4.5 Safety 4.5.1 General a. The subsystem, including software and procedures, shall be fail safe. b. For a catastrophic risk, the explosive subsystem shall be “Fail Safe – Fail Safe” or “Fail-Operational – Fail Safe”. c. The response of any explosive device to conditions outside the conditions specified shall be reported by the supplier to the end-user. d. The explosive subsystem shall only respond to commands intended for that explosive subsystem. 4.5.2 Prevention of unintentional function 4.5.2.1 General a. The firing pulse shall be prevented from reaching any explosive initiator at any time except the correct instant by means of switchable barriers. NOTE For example: · Firing pulse: detonating shock, electrical pulse, and light pulse. · Switchable barriers: electrical, mechanical, plugs, and pins.BS EN 16603‑33‑11 pdf download.