NASA recently announced that they plan to have astronauts in orbit around Mars within 25 years. Not to be outdone, Elon Musk boldly stated that he could prepare a mission to Mars within 10 years. Musk’s SpaceX plan would transport a hundred people to the red planet. Their mission wouldn’t be to visit Mars but to colonize it. In this episode of Space, Time Matt breaks down the challenges that the first humans on Mars would face and how they could overcome them.
“The energy needed for transfer between planetary orbits, or “∆V”, is lowest at intervals fixed by the synodic period. For Earth / Mars trips, this is every 26 months (2 years and 2 months), so missions are typically planned to coincide with one of these launch windows. The energy needed in the low-energy windows varies on roughly a 15-year cycle with the easiest windows needing only half the energy of the peaks. In the 20th century, there was a minimum in the 1969 and 1971 launch windows and another low in 1986 and 1988, then the cycle repeated.
Several types of mission plans have been proposed, such as the opposition class and conjunction class, or the Crocco flyby. The lowest energy transfer to Mars is a Hohmann transfer orbit; a mission to Mars using Hohmann transfer involves an approximately 9 month travel time from Earth to Mars, about five hundred days at Mars to wait for the transfer window to Earth, and a Hohmann transfer of about 9 months to return to Earth.
Shorter Mars mission plans have round-trip flight times of 400 to 450 days, but requires a higher energy. A fast Mars mission of 245 days 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 for 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 extending a flyby mission with a short stay lander. Basically, a short stay lander-ascent vehicle would separate from a “parent” Earth-Mars transfer prior to its flyby of Mars. The Ascent-Decent lander would arrive sooner and either go into orbit around Mars or land and depend on the design offer perhaps 10–30 days before it needed to launch itself back to the main transfer vehicle.” https://en.wikipedia.org/wiki/Human_mission_to_Mars