BS ISO 27875:2019 pdf free.Space systems一Re-entry risk management for unmanned spacecraft and launch vehicle orbital stages.
The scoring schemes for the severity of consequence of re-entry hazards are defined by the national authority. Based on ISO 17666, risk is assessed by the risk magnitude expressed as the combination of its severity and likelihood (see Annex B, and ISO 17666). The scoring is typically related to the casualty area (see 5.5.1.2) in the case of casualty risk, damage of properties in the case of social risk, or pollution on the ground In the case of environmental risk (for example, see Table Bi. or ISO 17666). Generally, a risk index will be defined as a combination of severity and likelihood, and a risk magnitude will be defined for each risk index. For assessing re-entry risk: — In the case of natural re-entry, Ec is calculated as a function of the casualty area, orbital inclination, and population density. Since the re-entry cannot be avoided without control, likelihood is fixed as the probability of occurrence of 1,0, and the risk index is equivalent to the Ec. Sub-clause 5S describes assessment procedures for casualty risk in the case of natural re-entry. Sub-clause £ for environmental risk. — In the case of cont rolled re-entry, Ec is calculated in the same manner as for the natural re-entry (i.e., isa function of the casualty area, orbital inclination and population density), but the Ec is weighted by reliability of functions and sufficiency of propellants needed for controlling the re-entry. (See Annex B or ISO 17666). Sub-clause 1.4 describes assessment procedures for casualty risk in the case of controlled re-entry. Proposed actions may be defined for each risk index (See Table B.3 and B.4, or ISO 17666.) Re-entry risk assessment actions (analyses, reports, etc.) shall be defined and scheduled, and a compliance matrix that correlates safety requirements against the system design and operation plan, which includes achieved quantitative results, threshold values, consequences of violating thresholds, and the probability that those consequences would be realized, shall be maintained. The expected output is the assessment parameters (e.g., risk to people on the ground and its associated nmthematlcal parameters) and their thresholds, or the concept for risk decision and the actions according to the severity of consequences and the likelihood of occurrence. NOTE 1 Several national governments and space agencies adopt 0,000 1 persons as an acceptable upper limit for Ec. NOTE 2 Generally, on-board radioactive substances, toxic substances, and any other hazardous materials are considered when evaluating and limiting the potentially adverse effects of re-entry on the Earth’s environment.BS ISO 27875 pdf download.