[dotnet00]

The article says they're going to be 144 meters apart. A collision of things that are in basically the exact same orbit is also not going to be much of a risk, as the collision would be at a low relative velocity. Collisions between satellites are a kessler syndrome risk because due to differing orbits, the collision velocities can be in km/s, which can spread debris into a wide range of orbits, thus causing the heightened risk of cascading failures.