Well, actually, they used to be NASA rocket scientists, but they decided that the current plan for replacing the shuttle, returning to the moon and going to Mars was fatally flawed.
Not the idea of doing those things, just the current NASA plan for accomplishing those goals.
So, after being marginalized, they branched off on their own and founded the Direct 2.0 initiative.
After looking over their plan, I have to agree with them. Their flight hardware architecture is quicker off the pad, more powerful, safer, more robust and offers more long-term options for crewed inner solar system exploration than anything I have ever seen.
These folks have really done their homework.
You can read their entire proposal in .pdf format here.
The full graphics are on flickr here
In the meantime, here are some space porn for ya...
I'm convinced these folks are on the right track.