BS ISO 27875:2019 pdf free download – Space systems一Re-entry risk management for unmanned spacecraft and launch vehicle orbital stages.
3) standard conditions of the break-up process and sequence (e.g., de-facto altitude of the aerodynamic break-up point where the space vehicle is assumed to be disjoined into a set of components, a specific value acquired from the analysis, etc.);
4) initial temperature when the analysis starts;
5) criteria for eliminating any components from the risk analyses due to their low survivability; and
6) threshold for minimum impact energy that causes casualty.
5.4 Identification of system/mission dependent parameters
The following data shall he obtained from those organizations that are responsible for the design and operation of a space vehicle:
a) the object’s physical characteristics, aerodynamic properties, and thermal properties;
b) orbital characteristics which define the initial point of re-entry analysis;
c) detailed characteristics of the space vehicle including its components (e.g., propellant tanks, pressurized vessels, major structural elements) and their architecture, mass, dimensions, shapes, connectivity, mutual shielding and nesting, and other factors (e.g., aerodynamic drag coefficient, coefficients for average heating); and
NOTE 1 Design data for deployment devices enable better estimation of the break-up point.
NOTE 2 It is important to list all of the components which are released when the space vehicle experiences break-up during re-entry. This is particularly the case for any components possibly surviving re-entry, and whose impact energy on the ground can be beyond the criteria defined in 5 b) 5).
d) properties of small but potentially surviving and hazardous objects that are likely to be released during re-entry.
5.5 Estimation of risk in the case of natural re-entry
5.5.1 Estimation of the number of casualties
5.5.1.1 Survivability analysis
A survivability analysis shall be conducted according to 5 and SA to confirm compliance with the requirements in 5.2, and its result of the analysis shall include a list of objects that survive re-entry and impact on the ground.
5.5.1.2 Casualty area
5.5.1.2.1 Definition of casualty area
To estimate the risk of human casualty, a “casualty area’ is typically defined as the average debris cross-sectional area plus a factor for the cross-sectional area of a standing individual which would have a “hazardous contact” with the “critical area of standing individual” (A1, critical). The total debris casualty area for a re-entry event is the sum of the debris casualty areas for all debris pieces surviving atmospheric re-entry. Here, “hazardous contact” is defined as contact that would cause casualty (injury or death); i.e., contact between an object which has an impact energy higher than the pre-defined threshold to prevent casualty and Ah critical which is vulnerable to such a threshold for impact energy. Sub-clause .C2 shows one of the traditional methods for the calculation of casualty area.