Sliver, gravity doesnt exist. I forget what holds them up, but the force keeping us down is the flat earth spiraling upwards at breakneck speed but we are held at position. I cant for the life of me remember I need to re-read the FAQ.
But on the topic of why the bloody hell we haven't gone to the moon again or sent people to mars.
During our trip to the moon a number of issues happened, some minor. A few very minor AMOUNT of major problems also happened. It also cost the US an arm and a leg and the whole state of Texas and Florida combined or so such. AKA, It cost alot.
The only gain we get from going to Mars is bragging rights, a few possible scientific leaps ahead. And that's about all I can list right now seeing as my head hurts from getting jogged in the jaw. (MMA/UFC Style Sparring/Grappling.)
Now, your going to have to understand some Round Earth style reasoning's as we understand your FE style reasoning's to understand the difficulties in going to mars/moon.
The Debt the US has right now is real, and Obama doesnt feel like funding NASA. NASA wanted to go to the moon again in 2011 (Or 2013 I think.) and asked for the funding in '09, Obama declined said funding seeing as it would have been somewhat wasteful of our money at the time.
Now, the SUPPLIES aren't the issue. The Technology to make the vehicle that is capable of holding Humans for extended periods of time, the fuel for such a trip. The cargo hold or bay for said growing or holding of food, and the air supply and protection (From solar rays, mini asteroids, possible technological malfunctions that always happen.) and workout areas for the crew and millions of other minor and major things required for such a trip are costly beyond belief. The required work is also quite the wall. A simple orbit around the earth is a sweat-filled task even. The Shuttle is a very high tech piece of machinery that has alot of maintenance. And they are aging and are planned to be put down (Decommissioned as the shuttles are going to hopefully be replaced by a new vehicle.) in 2011 or late '010.
I hope this at least helps you understand, and again if any of my points are wrong point them out to me, I have a minor headache and my jaw hurts from getting punched and my thoughts may not be clear.