> Orion doesn't have the necessary docking adapter. NASA actually enforced a standard docking systems for all capsules: https://en.wikipedia.org/wiki/NASA_Dock

> Orion doesn't have the necessary docking adapter. NASA actually enforced a standard docking systems for all capsules: https://en.wikipedia.org/wiki/NASA_Docking_System https://en.wikipedia.org/wiki/NASA_Docking_System . In theory it's androgynous so it might even be possible to dock capsules to each other. Orion is extremely heavy (26 tons fully fueled) so it would need a Falcon Heavy or D4 Heavy. This would make it very expensive. It's also politics: since the early 2010s SLS has been the only "supported" vehicle for Orion thus tying the two programs together.