When robots are as smart as humans, they will be able to explore Mars as well as humans. The Mars rovers move a few meters per day, requiring support from earth, which can be 20 minutes away by radio. Astronauts on the moon covered miles per day, stopping when something interesting popped up, like the "Genesis Rock".
Getting to Mars and backis technically feasible today, using in situ resource utilization. Check out Robert Zubrin's "The Case for Mars".
Not to mention radiation exposure.
The Mars Science Laboratory spacecraft was monitoring radiation exposure for the 8.5 months it took to travel to Gale Crater. Curiosity also has several radiation monitors, so NASA is beginning to put together a database on precisely how much radiation astronauts would be exposed to on a trip to Mars.
The good news is that this is the type of data that is needed to design spacecraft, suits and other systems for a manned landing by 2030.
Good point about gravity well, and also good points about why ultimately you gotta get perople there to really make it interesting.
The gravity well problem was handled in the lunar landings, with the landing modules. Of course on Mars, the problem would be worse. But I think the idea is going to be to keep the main craft orbiting around mars. I don't think Mars has the natural resources to allow a lot of refueling on its surface!
But I think there are other important problems to solve. One is keeping people in space for about a year and a half at the very minimum, with either no gravity, or much less gravity than on earth. And then have them survive the return to 1g.
And of course, the other problem is simply to have people isolated from all human contact and support for that long. Even basics like air and water, I mean. Didn't someone try such an experiment not too long ago? They didn't last. Needed an infusion of air at some point, as I recall. And maybe medical assistance too?
The comments above nicely summarized the different views about whether a "telepresence" on Mars is sufficient, or whether we need to send humans. The Curiosity is important for a number of reason, none the least of them being that we demonstrated the type of "power descent" that would be needed to land humans in a much heavier spacecraft on the surface. The problem we have not solved is how to leave the "gravity well" which is the planet Mars. That's why NASA is proposing missions to asteroids or the moons of other planet with smaller gravity wells. Until we figure out a way to generate the energy for a return trip from Mars or another planet, we'll have to continue sending these magnificent machines. Still, there is one other option for human exploration of Mars: Make it a one way trip. There are plenty of pioneers out there willing to volunteer for such a trip.
Robots are great research tools, but they cannot inspire. We will never leave our planetary cradle if we cannot send a few brave leaders ahead of us to show us it can be done. And, quite flatly, we must grow beyond Earth or we must shrink. We are barely holding on now. If we don't take the pressure off somehow we will face starvation and war. I would rather solve the problem in a positive way. We either voluntarily limit ourselves, or we find or build new places to grow.
Having said that, NASA has done a great job with this one. I hope that many benefits come from it. The next logical step is to develop a self-sustaining outpost. After all, packing two years worth of food is a LOT of cargo. Growing your own en route requires much less weight and isn't limited to two years.
NASA is getting better and better at landing on Mars, the last 5 or 6 attempts only one failed. If this trend continues, there is no need to put a human there in the near future. Let's just put more and more robots there.
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