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Originally Posted by BigJim
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Originally Posted by Grand Vizier
I'm all for a Moon First approach (perhaps with a few NEOs thrown in).
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Why? Antarctica, or even Wyoming provide far more Mars-like environments than anything Luna could provide, and at far less expense. Mars has an atmosphere, and a nearly 24-hour day. The Moon has no atmosphere and a 672 hour day. While Earth's gravity is about 2.5 times that of Mars, Mars's gravity is 2.5 times that of the Moon. In addition, the types of science you would do on Mars resemble the science which you would do on Earth far more closely than the scientific research able to be carried out on Luna. The Moon has no value as a training base for Mars missions. NEOs have even less.
While it is possible to mine oxygen from lunar rocks for rocket propellant or electrolyze water from the lunar poles to get propellant, it does not help for Mars flights to refuel at Luna. Even if infinite quantities of rocket fuel were sitting on the lunar surface right now - and they aren't - it would be, at best, ridculously illogical to refuel a Mars-bound spacecraft at the Moon. Why? Because before you can refuel at the Moon, you have to get there. Getting from the surface of the Earth to the surface of the Moon actually requires more Delta-V than going from the surface of Earth to the surface of Mars. So, from a propulsive point of view, it is much easier to send a spacecraft directly to Mars than to send it to the Moon first. Refueling your Mars craft at the Moon is like having a flight from London to New York stop over in Moscow for refueling. It just makes no sense. |
You are probably right that the Moon wouldn't provide a similar enough environment to Mars that you couldn't get right here with some work. But, for an extended mission of 3 years or so, we would need space equipment that is much more robust than we have now. Just think of all the things that break on our current manned craft all the time. It would be too difficult to carry the tons of spare equipment needed, so the equipment on the Mars mission would need to last in the space environment and the Mars enviroment for years. By placing a mission on the Moon first, you can test the equipment for years in space, while the crew is only 3 days or so away from Earth if something goes wrong. The time spent at the test site on the Moon would be great for developing the equipment, procedures, experience, etc, nearby to Earth before taking the years long journey to Mars.
Another concern I read about but hadn't thought of was medicine. The Apollo missions only lasted a few weeks at most, so illness wasn't too big a concern. But what happens to the Mars bound astronaut who develops appendicitis, or a fast acting cancer, or something else where you need a hospital? New medical equipment and maybe even procedures would need to be developed and tested.
Also, the psychological aspects of the mission can be tested while the mission is removed from Earth. Sure, you could set up a biosphere here on Earth and stuff people in it for 18 months, but the rest of the world is right outside the walls. If you run a mission on the Moon, not only do you have the problem of "I quit, open the door" solved by 250k miles of vacuum, but the increased tension of the deadly Moon environment just outside the walls. Mars isn't the Moon, but both are extremely deadly to humans.
So I think it shouldn't be 'only Mars' or 'only the Moon', but a plan using stations in orbit, test missions (and maybe a small base or two) on the Moon and then the long leap to Mars and beyond.
Kizarvexis