Weston Faber, L3 Applied Defense Solutions; Waqar Zaidi, L3 Applied Defense Solutions; Paul Schumacher, Jr., Air Force Research Laboratory
Keywords: Fragmentation blast point determination, Fragmentation, Breakup, GEO, Resident Space Object
Abstract:
As more and more objects are launched into space the potential for breakup events and space object collisions is ever increasing. These events create large clouds of debris that are extremely hazardous to space operations. Providing timely, ac- curate, and statistically meaningful Space Situational Awareness (SSA) data is crucial in order to protect assets and operations in space. Determining the point of initial breakup, the blast point, is valuable in order to characterize and model the event. A standard approach may approximate the blast point by back propagating the mean orbits from well tracked debris fragments to the time of closest approach. At this point orbits are averaged to determine the blast point. The errors in this ap- proach arise from the size of the debris object uncertainty, the un-modeled forces, and the uncertainty in the time of the breakup event. If these uncertainties are not accounted for biases in blast point belief can arise. In this paper, the authors discuss the complexities involved in this approximation and establish methodology to determine the influence of parameters such as the number of well tracked debris objects and the accuracy levels required to determine the blast point to a user defined level of accuracy. The authors then present a new approach that takes advantage of fragment state uncertainty to alleviate biases in blast point estimates. This will be tested using GEO fragmentation event simulated according to NASAs standard breakup model. When tracking fragments from such an event, one may receive a slew of uncorrelated observations and determine the orbits for some or all debris fragments. An approximation of the blast point can be calculated from the tracked debris fragments by back propagating their orbits to the time of closest approach then averaging the debris fragment orbits. The errors in this approach arise from the size of the debris object uncertainty, the un-modeled forces, i.e., whether or not the assumed underlying dynamics accurately represents the true fragment dynamics, and the uncertainty in the time of the breakup event. In this paper, the authors aim to characterize the number of tracked fragments and the level of tracking accuracy required to approximate the blast point to within a user defined level of accuracy. Then, the authors present a new technique that utilizes knowledge of the debris fragment state uncertainty to alleviate biases in blast point determination. The main contributions are as follows:
develop methodology to determine the level of accuracy of standard blast point determination techniques as a function of number of well tracked fragments and accuracy of well tracked fragments.
Provide a new approach for blast point determination that utilizes the knowledge of debris fragment initial uncertainties and uncertainty in underlying dynamics
. Provided approach can improve blast point determination accuracy with fewer tracked frag- ments and lower accuracy requirements.
Decreases time required to produce blast point approximation
Date of Conference: September 11-14, 2018
Track: Optical Systems Instrumentation