How can we identify colliding objects to be removed?

This paper discusses how we can identify colliding objects to be removed from the low Earth orbit region for sustainable space development and utilization for humankind. Here we compare two different approaches to identify colliding objects to be removed. One approach keeps a view on the possibility of multiple removals. Thus, this approach specifies orbital regions where objects arc crowded, and then compares mass between the objects in the crowded region to select candidates. Another approach thinks of impact on the current/future space debris environment. Thus, this approach compares the cumulative probability of accidental collision and/or the expected number of fragments added to the environment due to the accidental collisions to select candidates. Comparison in the effectiveness between the four different approaches in total will be conducted through future projections of the space debris environment in the low Earth orbit region. This paper uses NEODEEM, a space debris evolutionary model for the near Earth orbit region, to conduct this comparison.