Formulas for the phase characteristics in the problem of low-Earth-orbital debris

Some formulas and relations for estimating the characteristics of the different phases in the problem of debris propagation are suggested. The methods are based on the assumption of a weak isotropic explosion as the orbital breakup mechanism. This assumption leads to a simple formulation of the torus, the apsidal, and the nodal closure times. A criterion that guarantees the separation of the atmospheric dissipation phase from the nodal dispersion is suggested as well.