A document describes a series of models created for the determination of the probability of survival of critical spacecraft components from particle strike damage caused by hyper-velocity impact of meteoroids and/or orbital debris. These models were integrated with both shield design and hypervelocity impact testing to develop adequate protection of said components to meet mission survivability requirements.
Spacecraft configuration and construction were determined, including geometric shapes, dimensions, positions, material of construction, etc., for the spacecraft or component. The types and levels of damage allowable for each protected component were determined.
Critical damage was defined by the damage level that will cause loss of function of the protected component. Required probability of survival for the critical components was determined. This was done by determining the probability of survival based on exposure only, neglecting shielding. Next, a Monte Carlo simulation was run representing all possible particle impacts, collecting data on shielding-protecting components. An empirical physics-based model that estimates the incident kinetic energy required to cause critical damage to the component was applied to each Monte Carlo simulated particle strike.
This work was done by James G. Zwitter and Marc A. Adams of Caltech for NASA’s Jet Propulsion Laboratory. NPO-46082
This Brief includes a Technical Support Package (TSP).
Meteoroid/Orbital Debris Shield Engineering Development Practice and Procedure
(reference NPO-46082) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing the Meteoroid/Orbital Debris Shield Engineering Development Practice and Procedure (NPO-46082). It outlines the engineering processes employed by JPL's Impact Physics discipline to assess and enhance the survivability of spacecraft components against impacts from meteoroids and orbital debris.
The process begins with problem definition, where the configuration and construction of the spacecraft are analyzed. This includes understanding the geometric shapes, dimensions, materials, and positions of critical components, which are referred to as protected components. The document emphasizes the importance of identifying these components and determining the allowable damage levels, particularly focusing on critical damage that could lead to loss of function.
Following the problem definition, the document describes a preliminary assessment of the probability of survival for these critical components. This assessment uses inputs from the problem definition and threat characteristics to estimate the expected number of meteoroid impacts based on the exposed areas of the components over the mission duration. Poisson statistics are applied to calculate the probability of zero impacts, which is essential for ensuring that the components remain undamaged.
The threat characteristics section provides a statistical estimate of the meteoroid and orbital debris threats throughout the mission. The JPL Space Environmental Group typically utilizes the Interplanetary Meteoroid Environmental Model (METEM) to generate a bivariate distribution of impact velocities and the cumulative expected number of impacts for particles above a certain mass. The model assumes that meteoroids can impact from any direction, and it also considers the density of meteoroid materials. Additionally, the document mentions the use of the ORDEM model for estimating orbital debris fluence.
Overall, the document serves as a comprehensive guide for engineers and researchers involved in spacecraft design and protection against meteoroid and orbital debris threats. It highlights the systematic approach taken by JPL to ensure the safety and functionality of critical spacecraft components throughout their missions. The information is intended to support aerospace-related developments with broader technological, scientific, or commercial applications, and it encourages collaboration through NASA's Innovative Partnerships Program.
