Is there a relation between the mass of a satellite and its orbital altitude? I mean, will a heavy satellite orbit at a higher or lower altitude than a lighter one, considering everything else being equal?
While this question betrays a serious lack of understanding of physics, it's also a common lack of understanding, so I think it is in a way a good question.
We are used to helium balloons floating up into the air, wood floating on the surface of water, and cannon balls sinking to the bottom of the sea.
Intuitively, when we think of things "floating" in space we try to do it with the analogy of buoyancy because that's what we are used to, but the physics of buoyancy simply do not apply in a vacuum where there is no air or water pressure to "bouy" an object up.
When an object is in space, it is actually in perpetual freefall, nothing is holding it up against the force of gravity and it is constantly falling towards Earth with no resistance whatsoever, the force of gravity is unopposed. Because there is no resistance, the material properties of the object simply do not matter, explanations of this often involve a feather compared with something heavy.
Yet how can something be constantly falling but never reach the ground? The reason is because it is also travelling sideways at very high speeds, this causes it to take a curved trajectory that misses the earth. See Newton's cannonball for a visual example of how this kind of trajectory works.
Yes and no.
No: The equations that govern the orbit of a satellite don't say anything about weight, so if you launch a heavy satellite and a light one to the same orbit, they'll stay together.
Yes: In the equations that govern the launch of a satellite, weight is a variable. When you launch two identical rockets, one with a heavy payload and one with a light payload, the light payload will end up in a higher orbit.
The mass of the satellite definitely affects where it stays in the orbit (leo, meo or geo). Gravitational force between two objects is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them. If a balloon is launched about 2km away from the Earth, it stays up. With its mass and at that distance, the gravitational force on it could be zero. Same cannot be said of a metal ball of higher mass. Objects with higher mass will require longer distance for the force of gravity to be ineffective.