Examples of derived mass densities for two debris objects. (a and c) Average orbital altitude in black and orbital eccentricity in blue on the right y-axis. The dashed line shows eccentricity 0.0025, which is later used as an upper limit for the analysis. (b and d) Orbit-averaged mass densities from the JB2008 model in black and derived from TLEs. Gray shading indicates times when the eccentricity is above the chosen limit. The panel titles show object name, international designator (or COSPAR ID), and the catalogue number assigned to the object.