SpaceX Gives a Preview of Falcon X and XX

SpaceX Unveils Heavy-Lift Vehicle Plan, Aviation Week
“The U.S. government should lead development of a nuclear thermal propulsion system for a future Mars mission and leave new heavy-lift launchers to commercial entities, Space Exploration Technologies (SpaceX) says. Unveiling conceptual plans for a family of Falcon X and XX future heavy-lift vehicles at last week’s AIAA Joint Propulsion conference here, SpaceX McGregor rocket development facility director Tom Markusic said, “Mars is the ultimate goal of SpaceX.”
Keith’s note: These are two presentations from the meeting by Tom Markusic: “SpaceX Propulsion” and “SpaceX overview” (Broken links fixed)