DIRECT is a Space Transportation System derivative launch framework, designed as a follow-on to the Shuttle (STS) program. The concept is something of a rehash of past NASA studies into next-generation launch vehicles derived from the STS hardware and infrastructure.
I won't say too much more, but leave it to you to check out their site. Suffice it to say that I think it has potential, but is encumbered by silly presentational snafus such as misspelled or entirely wrong words/terminology (something I am somewhat critical of). It comes across as a first draft, really, although this is version 2.0 of the DIRECT plan.
It makes sense, however, which makes it all the more confusing that the concept hasn't naturally flowed out of the Shuttle program. Oh well. Perhaps more on this later.