This paper addresses the process by which the range safety of intercept tests are assessed. The methodology outlines procedures for consideration of the safety of space, airborne, and land fetures. A special emphasis is placed on the role of breakup models on the utility of the final result. Issues covered include determining hazards vs. avoidance zones, fragment propagation, the impact of breakup model fidelity or resulting simulations, and lethality limits for space/air/ground.
The development of debris environment analysis tools and correlation of space weather with satellite anomalies have progressed nearly independently during the space age. This paper proposes how these two fields may be merged to provide greater insights into the operation of satellites in the dynamic space environment. The combination of these two applications will provide a venue to corroborate the impact of debris on spacecraft while identifying the cause of previously 'unknown' anomalies. A conceptual approach as how this may be accomplished is presented using events to highlight the efficacy of this effort.
On at least six occasions during 1983-1992, operational debris released from the fourth stage of Russian Proton launch vehicles fragmented, creating up to 60 new trackable debris in Earth orbit after each event. Surprisingly, these fragmentations occurred 18 - 96 months following successful Proton missions. One month after the fifth incident in September, 1992, an international investigation employing American space surveillance data and analyses and Russian engineering knowledge determined the probable cause of the satellite breakups. Preventive measures are now being developed for future Proton flights. The unprecedented Russian-American cooperation leading to the resolution of this environmental issue should serve as a model for future investigations.
This paper examines the vulnerability of the international Space Station Freedom (SSF) to impacts by orbital debris. Impact by debris particles with diameters of 1 cm and greater upon certain components of SSF would cause the failure of that component. NASA has calculated the frequency of 1 cm diameter and larger particle impacts upon SSF using its orbital debris flux model (found in NASA document SSP 30425). This impact frequency has been used to calculate component reliability based on the probability that a component will be impacted within the given station lifetime and suffer a catastrophic failure. This paper examined NASA's use of the orbital debris flux model in these calculations and proposes that conservative estimates within the orbital debris flux model may cause underestimation of SSF component reliabilities. Probability of collision (PC) calculations based upon recent U.S. Space Command satellite catalog information coupled with reasonable multiplication factors for 1 cm debris are presented, which yield lower impact frequencies than those found using the orbital debris flux model. The resulting lower probabilities of collision result in higher calculated values for component reliabilities; values that compare favorably with the proposed NASA safety criteria. Possible reasons for the disagreement between methods are discussed.