There is a moment in a movie when they talk about it. Soyuz 7 is 6x15 meters and weights 20ton. Shuttle's cargo bay is 6x20 meters and has a capacity of 20 tons. Coincidence? They think not. And there is also a French guy in the Shuttle's crew who flew on Soyuz and is familiar with it.
However! One of the major plot points is how the station is rotating out of control, and that makes docking very, very difficult. In fact, none of the cosmonauts can do it in a simulator, so they have to go back to the main protagonist, who was decommissioned because he saw angels(?) during EVA.
Now imagine how challenging it would be to grab this rotating 20-ton object and put it into a cargo bay.
However! One of the major plot points is how the station is rotating out of control, and that makes docking very, very difficult. In fact, none of the cosmonauts can do it in a simulator, so they have to go back to the main protagonist, who was decommissioned because he saw angels(?) during EVA.
Now imagine how challenging it would be to grab this rotating 20-ton object and put it into a cargo bay.