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Mcknight, Darren

Publications and source records attributed to Mcknight, Darren.

Applications of a fast and efficient method for simulating orbital mission safety

A fast and efficient method for simulating potential interactions between space objects is presented. The specialized hazard analysis simulation is run at the Russian Space Surveillance Center. It simulates the motion of objects in space and determines close encounters between these objects. First, ephemerides are predicted for all space objects over the time interval of concern. Second, using the predicted ephemerides, pairs of satellites that would likely collide are grouped together. Throughout the process, the pairs initially chosen are refined until all pairs of satellites are found which come within a certain miss distance of each other. In addition to the miss distance, other characteristics of the encounter including angle of incidence, relative velocity, type of approaching object, and probability of collision come out of the simulation. There are many potential applications of this simulation and its results to missing planning and mission safety. Artificial objects can be introduced to the simulation to examine potential encounters between the new objects and current objects for mission design applications. The simulation can be run many times to create data for statistical analysis of encounter parameters. These as well as many other potential applications are presented and discussed.

Huth, Jeffrey↗

Analysis of shuttle window impact data

The Space Transportation System (STS) fleet has flown nearly 40 missions (as of November 1990) over the nearly ten years since its first flight. As a result of encounters with on-orbit particulates (space debris and micrometeoroids), atmospheric debris (ice, insulation) or ground damage 37 impact features (chips) have been found on the STS outer windows. Nearly half of the chips were large enough to warrant replacement of the window. The frequency and magnitude of these impact features are correlated against window location, mission duration and altitude, and date of flight. Interpretation of the results into number and size flux rates requires an understanding of STS operations. The data from the weeks of on-orbit exposure provide a small glimpse as to the effects that space debris and micrometeoroid impacts will have on fused silica components of systems that will remain in altitudes between 300-500 km for long periods of time.

Mcknight, Darren↗