How to get people from Earth to Mars (and safely back again) – Inverse

There are many things humanity must overcome
before any return journey to Mars is launched.
The two major players are NASA and SpaceX, which work together intimately on missions to the International Space Station but have competing ideas of what a crewed Mars mission would look like.
Size matters
The biggest challenge (or constraint) is the mass of the payload (spacecraft, people, fuel, supplies, etc) needed to make the journey.
We still talk about launching something into space being like launching…

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