HOUSTON --We are eight days away from the final shuttle mission, and this mission does come with some specific challenges. The biggest challenge is that they don't have a rescue mission, since there aren't any more shuttles left should something go wrong. But if something does go wrong, they'd just hang out at the space station for up to a year until Russian rockets take them home. Another big challenge is the size of the crew. They're only four people; usually there are six or seven. That means they'll have to work a little harder, especially at launch and at space walks to get all the cargo from one spot to the next. But they've been trained on all that, and they say there's little left to be done. With eight days to go until the shuttle goes to space for the last time, this crew isn't looking for any more time to train. They're ready to go. "Just leading up to the final launch, just eight days away, it sounds so final. I don't think we want more time. We're ready. We're trained and we want to go do it and we want to go do it on time," shuttle commander Chris Ferguson said. This crew of four has trained for just nine months, which is also shorter than a usual. But they're all shuttle veterans and their mission, while as dangerous as any other, isn't all that complex. The shuttle Atlantis is basically a delivery van on the way up to space and a garbage truck on the way down. "That's what it comes down to: how quickly can you do what you need to do," Ferguson said. The shuttle is taking 8,000 pounds of supplies to the space station -- everything from a computer printer to a treadmill track to food. There is lots of food -- 2,500 meals, which is enough to feed the U.S. Space Station crew for nine months, and it all has to be moved by hand. It's easier to do in Zero G but still a lot of work. "It's fun to fly around with these bags back and forth, and it's demanding from the viewpoint that you're always in motion and it's actually mentally demanding because you have to keep track of what you transferred," astronaut Sandy Magnus said. And once they are done, the shuttle is done. Thirty years of history and it all becomes history. America's greatest spacecraft ever designed will be grounded and its brave astronauts looking at an uncertain horizon. "The next person that flies a US rocket into orbit probably will not have a NASA badge. It probably will have a badge that has a Boeing or Space X or Sierra Nevada, which is kind of an interesting concept," Ferguson said. It is kind of an interesting time for NASA. By the time the nine months worth of food they're bringing up next Friday runs out, it's likely a commercial space craft designed in the United States will be bringing the next meals up to space. All the shuttles will be sent to different cities in the U.S., although Houston isn't a recipient. That is something that Ferguson says he's not too happy about.