Going to outer space is a little like going camping. You have to carry with you all the food and equipment you need for your trip, so your food can't be too heavy or hard to prepare. Plus, there are no refrigerators to keep food cold and fresh.    Food with all the water dried out is lightweight and doesn't spoil. So, many space foods are dried on Earth and stored in special packets. Some taste good right out of the packet.    On earth, gravity is the force that keeps your feet on the ground and your sandwich on your plate. But there's no gravity in space. To keep food from floating away, astronauts on the Space Shuttle attach the packets to a special tray. The tray can be fixed to a wall or to the astronaut's lap. To prepare their food, astronauts use liquid  forms of salt and pepper. The liquid sticks to the food better. Regular salt and pepper would float away, maybe up an astronaut's nose. Liquids float right out of cups and glasses, though. So astronauts drink everything from a small bag with a straw  that can be closed. Astronauts say that most space foods taste pretty good. Some, such as apples and pudding, are the same as the foods you eat on Earth. Astronauts eat tortillas  instead of bread because they make fewer crumbs . Floating crumbs could get stuck in equipment or an astronaut's eye. Your body used food in space the same way it does on Earth. Your body must deal with waste in space too. During takeoff the landing, astronauts can't leave their seats to go to the bathroom. They wear diapers  under their spacesuits instead. The Space Shuttle has a bathroom the size of a small closet. The toilet has bars that keep astronauts from floating away. A strong flow of air is used instead of water to flush  waste down the toilet. Back on Earth it's flushed away-or sometimes studied by scientists. What is the passage mainly about?
Astronauts' hard life in space. How astronauts go to the bathroom. The various foods astronauts eat in space. How astronauts eat and deal with waste in space.