EventRate: Algorithm and Software to Estimate Serious Conjunction Rates for Earth-orbiting Satellites

About this technology

Overview

The EventRate algorithm and software estimates the rates at which proposed Earth-orbiting satellites can expect to experience serious conjunctions. Serious conjunctions are close-approach events with other satellites that have collision probability (Pc) values exceeding a threshold (e.g., Pc > 1e-4) that prompts collision risk remediation maneuvers (RMMs). The software approximates the orbital parameters of the conjunction events by using those archived for one or more current or preceding satellites with a similar orbit, as recorded over the last several years within NASA's Conjunction Assessment Risk Analysis (CARA) database. The software uses the semi-empirical algorithm described by Hall (2019, Determining Appropriate Risk Remediation Thresholds From Empirical Conjunction Data Using Survival Probability Methods, AAS Astrodynamics Specialist Conference, Portland, ME, Paper AAS 19-631, 2019) which allows the user to input the proposed satellite's hard-body radius, the RMM commit and consider times, and total on-orbit mission duration. The primary output of the software is the estimated rate of serious conjunctions in units of events per year, along with an estimated 95% confidence interval. The program also estimates the cumulative Pc values over the on-orbit lifetime of the proposed satellite mission. The software allows pre-launch trade-space analyses of several satellite and mission parameters, including: satellite HBR, on-orbit lifetime, RMM Pc threshold, RMM commit and consider times, RMM type (translational vs rotational), tracked catalog growth factor, and CARA orbital regime.