Heavy Lift Rocket Standoff on Capitol Hill, SpaceRef

"There is a cottage industry these days - inside and outside of NASA - wherein people speculate what Heavy Launch Vehicle (HLV) design NASA is or is not pursuing. Everyone has Powerpoint charts, meeting notes, etc. but no one has all the facts. Nor are they likely to for months. The leaks have become a blur. NASA has not made its mind up yet and is not due to report back to Congress until June 2011 according to senior agency sources. That lack of clarity was evident in a presentation made by NASA Administrator Charles Bolden at a Space Transportation Association (STA) lunch briefing in Washington, DC on 25 March 2011."

Bolden Wants to Build Evolvable HLLV, Not the One Congress Wants, Space Policy Online

"In response to a question from NASAWatch editor Keith Cowing, Mr. Bolden explained that he does not think that the 130 metric ton lift capability prescribed in the law is necessary today and is not sure the agency can do it. He wants to build an "evolvable" launch vehicle, working in "small incremental steps [to] demonstrate that we can keep to cost and schedule and then people will begin to have confidence that we know what we're talking about.... There are things I do not know. ... I don't know what my 2011 budget is ... and that plays a critical role in what I can do."

Bolden and "evolvable" heavy-lift launch vehicles, Space Politics

"However, it wasn't clear from Bolden's comments whether what emerged from those studies would meet the act's requirements for payload capacity and schedule. Asked why the agency could't just announce that it would develop the vehicle in the act, Bolden said, "Because I don't want to, for one thing, and because it may be that we can't do that. We don't know." (It's unclear whether Bolden meant that he doesn't want to build the SLS as specified in the act, or instead meant that he doesn't want to say now that NASA will build such a vehicle; he later claimed he meant neither of those things.)"