Monitorization of the relative Minimum Orbital Intersection Distance (MOID) between terrestrial orbits

This final work presents a new tool for the rapid calculation of the Minimum Orbital Intersection Distance (MOID) evolution between objects orbiting the Earth. It is primarily intended as a filtering stage (the second filtering stage proposed by Hoots) for the assessment of the collision risk between a selected object and a huge number of detected and potentially dangerous space debris. The tool combines: •??The speed of a new orbit propagator developed by the Space Dynamics Group of the Technical University of Madrid (SDG-UPM) called DROMO (SDG-DROMO); •??The rapidity of MOID computation given by a new available routine developed by the same group (SDG-MOID). The result is a routine (SDG-DROMOID) which sequentially applies the former tools. This modular design guarantees the possibility of an easy replacement of any of the tools whenever an improved version were available. Briefly, the modus operandi is the following: 1. Download of the TLE list given by the NORAD for a huge number of space debris (ideally all the public objects tracked by the NORAD). 2. Propagation of every object and the primary object for a given period of time. This propagation passage is made considering only the Main Problem (the analysis of the perturbed motion of an object under the influence of the J2 term of the Geopotential expansion). 3. Calculation of the MOID at every step of time where the two objects osculating orbits are available. 4. Record of the evolution of the MOID between the primary and the space debris given by the NORAD in the studied period of time. 5. Analysis of the MOID variation in the selected period and possible conclusions that could be drawn (MOID decrease or increase, global minimum of the MOID, ability to discard objects without any possibility of impact in the considered period). Between all spacecraft, the International Space Station (ISS) is an object of particular interest for its relevance. For this reason, the method is developed and tested using the ISS as main target.