How the Bigelow module added to ISS will change the space equation.
Looking a bit further down the road, the potential launch of a Bigelow BEAM module, particularly if it takes place on a SpaceX Falcon 9 booster could be a harbinger of much greater things to come. As Mars visionary Robert Zubrin and many others have observed, the addition of an inflatable module similar to that being considered for the station, to the SpaceX Dragon 2.0 capsule greatly increases the available space and capability of a future Dragon to serve both as a Mars transfer vehicle, and / or surface habitat. Add in the introduction of Falcon Heavy, and the pieces for an alternate vision of far more affordable (and timely) inner system exploration begin to fall into place.
Stewart Money has it exactly right. I have never accepted the claim that Orion was the only spacecraft being built that would be capable of going beyond low earth orbit. Add the right components to any manned vehicle, and you have an interplanetary spaceship.
The trick of course is adding the right components. For both Orion and Dragon, the present assumptions are much too nonchalant about what those components are. For humans to prosper on an interplanetary mission, the vessel requires a lot more than a mere capsule and single module.