I was just wondering what variables are involved in a dead satellite deorbiting and fully burning up in the atmosphere. How much does mass/density/entry angle/velocity matter in the situation? If you were purposefully deorbiting something for destructive reentry, what would the ideal conditions be?
Re-entry and orbital debris analysis is complex. Here is the NASA standard for Orbital Debris Mitigation. For US launches, satellite operators are required to submit a document known as an Orbital Debris Assessment Report (ODAR), an analysis that shows a spacecraft will enter autonomously before 25 years on orbit (for LEO spacecraft), and that there is a small probability of re-entry hazard.
This analysis is performed, in part, by using a NASA provided tool known as Debris Assessment Software.
Here is an example of an ODAR for the Skycube 1U cubesat.