I just read an article on National Geographic about a private space company that will be sending a couple on a fly by of Mars in 2018.
Millionaire Dennis Tito, who in 2001 paid $20 million to spend 6 days on the international space station and hence become the first space tourist, is behind the non-profit venture. The plan is to develop a spaceship and send two people on a fly by past Mars in January 2018, when Mars and Earth are at an especially close point in their 15-year cycle.
From Nat Geo:
The plan is to send a man and a woman in a capsule around Mars for a flyby mission similar to the one that surveyed the moon before the Apollo landings.
Why a man and a woman? Tito and his team say the spacecraft they envision would accommodate only two astronauts. Once that was decided, they committed to having both sexes represented as the Earth’s first ambassadors to deep space, saying that to do otherwise would misrepresent humanity.
The plan is also to pick a couple in their 50′s. The reason for this is also tied to the main design problems for the mission. In space they will be encountering a massive amount of radiation, and while all efforts will be taken to mitigate this, they may still receive a large dose. An older man or woman would have statistically fewer years to live after their return than a young person, and so would be less likely to develop the cancers that radiation could bring.
The design of the mission is substantially easier than that of Curiosity landing on Mars, because they are simply doing a fly by, but there are still some significant challenges to overcome in sending two humans on a 501 day mission.
For more info check out the National Geographic article here.