Dennis Tito, the man trying to mount a privately funded fly-by mission of Mars in 2018, is considering the Space Launch System being developed by NASA’s Marshall Space Flight Center as his astronauts’ ride to the red planet. A Marshall spokeswoman confirmed Wednesday that Tito and another executive of his Inspiration Mars non-profit organization, visited Marshall March 19 for a briefing on SLS. Marshall is leading development of the booster part of the new heavy-lift rocket for NASA. An April 3 Inspiration Mars feasibility analysis on the website of the American Institute of Aeronautics and Astronautics lists SLS as an optional launch vehicle along with a SpaceX Falcon Heavy rocket and the big versions of the Atlas and Delta rockets assembled by United Launch Alliance in Decatur, Al. The Falcon Heavy has not flown yet, either, but ULA has launched both Atlas and Delta rockets successfully.