The reason why they are actively shutting it down, is that they are running low on fuel, and want to ensure that the spacecraft does not litter important orbital locations.
Gaia has spent its life at Earth's L2 Lagrange point, which is a valuable and limited area of space; they do not want to have to plan around dead spacecraft in future missions. Thus, before the spacecraft runs out of fuel, they have moved it away from L2 into its final graveyard orbit.
It is not capable of performing the science for which it was designed in its graveyard orbit.
The reason why they are actively shutting it down, is that they are running low on fuel, and want to ensure that the spacecraft does not litter important orbital locations.
Gaia has spent its life at Earth's L2 Lagrange point, which is a valuable and limited area of space; they do not want to have to plan around dead spacecraft in future missions. Thus, before the spacecraft runs out of fuel, they have moved it away from L2 into its final graveyard orbit.
It is not capable of performing the science for which it was designed in its graveyard orbit.