Shorter Mars mission plans have round-trip flight times of 400 to 450 days,Wernher von Braun, or under 15 months, but would require significantly higher energy. A fast Mars mission of round trip could be possible with on-orbit staging. In 2014, ballistic capture was proposed, which may reduce fuel cost and provide more flexible launch windows compared to the Hohmann.In the Crocco grand tour, a crewed spacecraft would get a flyby of Mars and Venus in under a year in space. Some flyby mission architectures can also be extended to include a style of Mars landing with a flyby excursion lander spacecraft. Proposed by R. Titus in 1966, it involved a short-stay lander-ascent vehicle that would separate from a "parent" Earth-Mars transfer craft prior to its flyby of Mars. The Ascent-Descent lander would arrive sooner and either go into orbit around Mars or land, and, depending on the design, offer perhaps 10–30 days before it needed to launch itself back to the main transfer vehicle. (See also Mars flyby.)
