From among many different options mulled over by NASA, the decision was ultimately made to design the International Space Station to provide the most pristine zero-gravity environment possible, in order to facilitate experiments involving everything from physics to the life sciences. This single requirement alone creates enormous architectural challenges, which have compounded the cost and complexity of the project.

Most satellites are much farther inclined to the station's orbit than one degree. Similarly, most satellites don't have the propellant available to change their own orbit plane, so they can't come to the station. A tug would require a lot of propellant for two round-trips—one trip to fetch and a second to reposition the satellite. Since most satellites fly much higher than the station and are in vastly different orbits, it would take too much propellant mass to consider changing orbits to retrieve them. (Note: the very limited time that a launch site lines up underneath the orbit plane of a satellite or a space station is the reason why there is such a short daily launch window for a rendezvous mission. We simply can't afford the propellant to change orbit planes if we don't get it lined up right in the first place.)

Even if one chose to accept the risk of handling a spacecraft inside a human-occupied sealed vessel, we would face the final problem of how to build a chamber wide enough or a doorway strong enough to get a large spacecraft inside. The aerodynamics of launch vehicles limits the diameter of the payload to about five meters. Even assuming you chose to work with only a few centimeters' clearance between the walls, we would have the problem of getting the spacecraft in and out the end of the chamber. A five-meter hatch against atmospheric pressure must withstand nearly 200 tons of force, meaning that the bolts and seals would have to hold one ton of tension for every 16 centimeters. This leads to some massive framing and bolts (or hooks) that would cause even a very crowded hangar to be a difficult thing to design, build and launch.