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Most of the mass (fuel) will be waiting in orbit. They need to bring down to the surface only the fuel to get back to orbit so they won't need half of a Saturn V. They still need to launch a lot of fuel from Earth.



I wasn't thinking about the whole journey back home, just the first part of it which looks damn hard to me: how do you get a space craft away from Mars? You need to reach escape velocity, and that's 5 km/s (> 11000 mph).

You'll have to build a complete launch site for that.


If you have fuel in orbit you just have to reach it, you don't have to get to escape velocity.


OK, got that. Did some further reading (again) on the topic and it's still about 4 km/s to reach the orbit. People are working on it, but for what I read it looks hard to overcome for 2030...


You still have to match velocity with the fuel. Crashing into your fueling station at 10000 km/h doesn't help anything.


Actually... it completely solves the problem of the return trip.


Somebody needs to teach NASA to embrace Crash-Only Design.


The Design Reference Mission calls for generating the fuel on the Martian surface, so you only need to drop a small amount of hydrogen feedstock to make the rest.

You need a huge launchpad to launch a 100 ton vehicle. You don't need it for something weighing only a few tons.


Easier to manufacture the fuel on Mars. It only has 40% of Earth's gravity, so easier to lift to waiting orbital fuel depot.




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