NASA has unveiled a bit more information about its current strategy for sending the first humans to Mars. The space agency plans to send a minimal crew to Mars in a 400,000kg spacecraft.
The space ship will be assembled in low-Earth orbit and will use three to four Ares V rockets. The cargo lander and surface habitat would be sent to Mars separately, launched before the crew in December 2028 and January 2029. The manned spacecraft will be dispatched in February 2031 and the trip to Mars will take six to seven months.
Once there, the crew will spend up to 16 months on the Martian surface before returning back home. NASA estimates the total trip may take as long as 30 months but many thing are still uncertain as the space agency is still in the early stages of planning this ambitious mission.
According to the Nasa presentation seen by BBC News, astronauts could grow their own fruit and vegetables on the way.
Once there, astronauts could spend up to 16 months on the Martian surface, and would use nuclear energy to power their habitat.
But the document points out that options for aborting the mission or furnishing the crew with new supplies would be extremely limited.
The difficulties of re-supply mean the astronauts would have to be remarkably self-sufficient.
They would need to be well-versed in the maintenance and repair of equipment and perhaps even able to manufacture new parts.
The total estimated costs of mounting a manned Mars mission vary enormously, from $20 billion to $450 billion.