# Evaluation of hazard for linear objects in case of launch vehicle failure in flight phase

 1Hladkii, EH1Yangel Pivdenne State Design Office, Dnipro, Ukraine Space Sci. & Technol. 2019, 25 ;(4):22-28 https://doi.org/10.15407/knit2019.04.022 Publication Language: Russian Abstract:  Impact areas of failed launch vehicles (LV) cover territories with gas and oil mainlines, railways, transmission facilities, rivers, etc. Damage to such industrial objects as gas and oil pipelines in case of a crash of failed LV could result in disastrous effects. For example, damage and burst of gas mainline would result in leakage of transported natural gas with a subsequent high-power explosion and heavy fire. In calculations of safety, these objects should be considered as linear (one of their geometrical dimensions essentially exceeds the other), and they represent a particular case of an areal object (traditionally, safety at LV launch is considered for areal ground objects).        The article presents the mathematical model of safety estimation for a mainline in case of LV contingency in flight. To estimate safety, the part of the pipeline within the failed LV impact area was considered as a set of individual rectilinear sections. Henceforth, a total hazard for a pipeline is obtained as the summation of risks of damage of its individual rectilinear sections. “Hazard” implies the probability of a drop of failed LV or its fragments on pipeline rectilinear section impact area. We have built the geometrical model and obtained mathematical expressions to estimate the risk of an individual pipeline rectilinear section damage. As an example, we took the procedure of the risk estimation for gas mainline “BukharaUral”, located within the impact area of Dnepr LV, that could be damaged in case of launch vehicle failure at the first stage of the flight phase. The mathematical model is universal and could be used to estimate the risk of damage of other linear objects within an impact area of failed launch vehicles. Keywords: flight safety, impact areas of failed launch vehicles, launch vehicle, linear object, risk
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