The Dragon capsule is a bit less capable than one would like in that it can't actually dock. That's what makes the Soyuz necessary and NASA's whatever-they're-

The Dragon capsule is a bit less capable than one would like in that it can't actually dock. That's what makes the Soyuz necessary and NASA's whatever-they're-calling-it-this-week capsule necessary. Technically the Dragon is "berthing", in that the space station's arm is what's actually bringing the two craft together, and any failure in that arm would render Dragon unable to connect or disconnect from the station.