I know that one of the main hurdles to a Mars mission is the sustainablity of the crew and equipment for the length of time it would take to get there and back. (That means food, water, air, and the crew not going insane from boredom/confinement)<br /><br />I know the mission has to be quite long and mostly that is because #1 the trip is 6 months long, and #2 you can only go there or come back near the Earth/Mars opposition, which means you have to wait for the next one.<br /><br />But if we were to develop an extremely powerful propulsion system some time in the future, would it be possible, maybe by using a highly excentric Hohman transfer orbit, both there and back, to go there and come back using the same opposition? I mean taking a month to get there, spend a month, and return in a month or so, starting before the Earth passes Mars, and leaving maybe just as it does or shortly after. How much more propulsion power would it take to get out there and back in that amount of time? My totally wild uneducated guess is about 10 to 15 times the power we are able to muster now. <br /><br />If you accelerated at 1g out of Earth orbit for half the trip to Mars, and then decelerated at 1g for the other half, I wonder how fast that would get you there in.<br /><br />Seems like the bottom line is that wee need a lot more "oomph" to do any decent manned exploration, and until then we are stuck with robotic probes.<br /><br />Heyo<br /><br />PS. This has me curious about another side question I had. How much thrust would it take to leave earth orbit and put yourself in a retrogade orbit around the sun roughly the same size as Earths orbit?