[cheerfulgreek]

Just like you have to wait for Earth and Mars to be in the proper postion before you head to Mars, you also have to make sure that they are in the proper position before you head home. That means you will have to spend 3-4 months at Mars before you can begin your return trip. All in all, your trip to Mars would take about 21 months: 9 months to get there, 3 months there, and 9 months to get back. With our current rocket technology, there is no way around this. The long duration of the trip has several implications.
First, you have to bring enough food, water, clothes, and medical supplies for the crew in addition to all the scientific instruments you will want to take. You also have to bring all that fuel! In addition, if you are in space for nine months, you will need a lot of shielding to protect you from the radiation of the Sun. Water, and cement make good shielding but they are very heavy. All together, it is estimated that for a crew of six, you would need to have 3 million pounds of supplies! The Shuttle can lift about 50,000 pounds into space, so it would take 60 shuttle launches to get all your supplies into space. In the history of the Shuttle, there have only been about 90 launches, and there are less than ten launches per year... So with the shuttle, it would take six years just to get the supplies into space. For this reason, you would probably need to develop a launch system that could lift more than 50,000 pounds into space. Even with a better launch vehicle, it is unlikely that you could launch the Mars mission all at once. You will have to launch it in several pieces and assemble them in orbit.

This kiddy cut and paste was so cute. Actually, if we do the research we could use the resources on Mars cutting cost on some of the supplies.