Dead Orbit is probably a Moon-centric group.

by NsU Soldier , Washington, Thursday, April 18, 2013, 18:05 (4025 days ago) @ Monochron

This has probably been brought up before but in reading over at Destiny Hub I came across the icon for the Dead Orbit Faction:

The large circle is the Earth, the small one is the Moon. The outer ring represents the Moon's orbit, the black shape surrounding the Earth and the Moon represents the Earth's gravity tidally locking the Moon into place, or a Dead Orbit, if you will.

I'm also going to take a bit of a shot in the dark and guess that the symbol further points to that large circle being Earth. The big symbol may represent the sun, and the three lines under it represent that this is the third planet from it.

And the Moon was not described to have ever supported life in the Destiny universe (so far at least). Sure, it once had(has?) mines and bases and such, but the satellite itself was not capable of an atmosphere to support life on its surface. This could give a double meaning to the name *Dead* Orbit. (Apparently, even Mercury was once terraformed and habitable, and that was my only other guess for what the Dead Orbit emblem was about.)