Space debris collision avoidance using a three-filter sequence

In the last few decades, the amount of space debris has dramatically increased, and this trend is expected to continue in the near future. Thus, there is a real risk that two objects in space orbiting about the Earth might collide. Consequently, an effective method for the detection of collisions is required in order to systematically prevent the creation of new space debris, or to study the evolution of the population of space debris after a collision occurs. This research is focused on objects orbiting in the exosphere - in low Earth orbits (LEOs) - because in the past decades these have produced the most serious damage. The methodology proposed in this paper consists of reducing the number of possible pairs of pieces of space debris into a shortlist of possible pairs at real risk of collision, using a filter sequence. This method is achieved by the following two procedures. First, an interpolation ephemerides table is built to compute the state of all the objects at several instants of time. Secondly, using the interpolation ephemerides table, the number of pairs at risk of collision is reduced by three filters. The first two filters are based on the geometry of the orbits and try to exclude pairs not undergoing orbit crossings, while the third filter searches for a time of coincidence. As a result, we have designed a powerful tool that can be used to avoid collisions between pieces of space debris.