Meteoroid and orbital debris (M/OD) shielding concepts for utility lines on the International Space Station

The future International Space Station has many wires and fluid lines that provide functionality to systems which are essential to the operation of the station. Many of these lines are routed along an open pre-integrated truss structure and are exposed to the space environment. It is therefore necessary to provide a certain degree of protection for these lines from micro-meteoroids and orbital debris (M/OD) in order to minimize line failures and the astronaut Extravehicular Activity (EVA) time required to repair or replace them. In a joint effort, McDonnell Douglas Aerospace and NASA's hypervelocity test team conducted a series of tests to verify shielding concepts for wire harnesses and fluid lines on the International Space Station. These tests included lines housed in protective aluminum carriers called the Utility Distribution System (UDS) and alternatively, a nextel beta-cloth wrap used to shield individual wire harnesses. Thermal blankets that cover fluid lines primarily for thermal protection were also examined to determine what degree of protection they may offer from a M/OD impact. From the test results and subsequent analysis, the total reduction in line failures was estimated for each shield design. These shielding methods often doubled the ballistic limit of the utility line and reduced line failures by as much as 80%.