Originally posted by: Jeff7
I seem to recall reading too that there are concerns over the long-term effects of the microwave radiation passing through the upper atmosphere, in that it might cause unusual heating.
Another problem is the slow "erosion" of the satellite by micrometeoroids and orbital debris. Which of course adds to overall costs to to expenses of building replacement parts and sending them into orbit.
Right now, I think it'd just be easier to use solar panels here on Earth. No concerns about sending the power long distances, no problems with lofting huge amounts of materials into orbit, no problems with a powerful microwave beam piercing through the atmosphere, minimal maintenance costs, etc etc.
The Humans to Mars thing - that has other issues. Namely, Martian dust and cosmic radiation. Lunar dust was a bad enough problem. Martian dust is also mildly corrosive, and it could be toxic. And then there's cosmic (and solar) radiation. There are currently no feasible artificial methods of stopping high energy cosmic rays. Scientific American discussed this. There are ideas for extremely powerful EM fields to protect a ship's inhabitants, but these fields themselves could cause health problems. That, and they'd require currently nonexistant power supplies to generate. The other option - a spherical ship with a shielding layer of water. I don't remember how thick it needed to be, a meter maybe? But it would give the spacecraft a HUGE amount of mass, thus making it insanely expensive to launch. Then there'd be the matter of accelerating and decelerating that mass to get it to Mars and back.
So yes we can get humans to Mars. Alive? Probably. Healthy? Not likely. Get them home alive? Less likely. Have them survive after getting home - almost no chance. Cellular and DNA damage from the radiation environment of space would be too severe to correct.
Robots are the way to go for now. They can be folded up into a tiny space, they don't need to eat or excrete anything during the voyage, and they don't whine and complain if you literally work them to death. They also don't have any strong desire to return home.
