NAC minutes and presentations are public-record, Federal Register-announced kinds of meetings, so SpaceX had to scrub our talk with regard to anything proprietary that was not ready to go public. But that was easy. The presentation itself elicited more nods than frowns, and those were mostly from folks with some specific stake in the current Mars architecture (aimed at sample return beginning in 2018). It threatened to turn into a design review, at times, which was a good thing. And it made an impact... one guy afterward came up and complained that we were making his life harder (by proposing to land a ton on Mars for Discovery-level budgets) and that he'd regretfully have to call our Center Director. Attempts to quash our work are actually good news, in the sense that we're on-target and taken seriously.
Afterwards, we spent the afternoon meeting at SpaceX's DC offices and then giving another briefing over with the new-business folks at APL. Things are beginning to stir up... I'm fond of challenging established orthodoxies and powers-that-be. (This gets me in trouble at times socially, of course ;-).