What properties of an orbit in a vacuum would be affected by the density of the object? Its mass is negligible compared to Earth & Moon no matter its configuration and material. AFAIK, whether hollow or solid, feathers or lead, it’ll orbit the exact same path.
“First, the object is likely man made. The motion of this body over about two years can be modelled in detail only if the effects of solar radiation pressure are taken into account.** The intensity of this solar push is proportional to the object’s area-to-mass ratio, which can therefore be estimated, providing an indirect clue to its density. **It turns out that this body has a mean density that is about 10% that of water. This is too low to be a natural space rock, but it is compatible with being a hollow shell, such as the spent upper stage of a rocket.”
I’ve been interested in “space junk” for a while now. It would be cool if they could somehow figure out what this object is and where it came from before it burns up in the atmosphere.
It may well survive. If it’s hollow, it will slow down in the atmosphere. I bet it’s a stage of an Apollo rocket. Just a cylinder that’s been floating around.