The absence of detail is something that has cropped up as a recurrent criticism of Nasa's own initiative, named "Journey to Mars" - a response to the Red Planet vision announced by President Obama six years ago.
Earlier this year, members of Congress and expert witnesses claimed the US space agency lacked a clear road map for Mars and that the plan needed achievable milestones to succeed.
However, this has apparently not dented President Obama's enthusiasm for expeditions to the Red Planet.