Yes, well first you hydrate it then you eat or cook it in a microwave or oven.
NO. Space food is the same sort of food you and I eat, except that it's vacuum-packed and bottled, sometimes put into a paste to make it easy for the astronauts to eat.
Space food is packed into frozen parcels. You have to heat it first to eat it.
Astronauts take vacuum packed food into space so that it is preserved. Although, if you think about it, this is quite strange because there is no atmosphere in space and therefore how can it go off ? Anyway, I digress, for lunch an astronaut would eat Starbucks.
Astronauts eat a variety of specially-designed foods while in space, such as dehydrated fruits, vegetables, meats, and desserts. These foods are vacuum-sealed and freeze-dried to preserve them without refrigeration and are easy to rehydrate for consumption in microgravity. Additionally, astronauts can also enjoy beverages like coffee and tea in space.
they eat the packed food
No. In fact, they'd be quite dangerous.
You eat only space food in space. This food is maintained specifically for the people that are going to space.
Astronauts eat dried food, or, really really well packed food. They pack food really really good by sucking out all of the air inside the package. When they eat the dry food, they add water through a little tube.
Astronauts cannot eat foods that produce crumbs or loose particles, such as bread or chips, as they can float and become a hazard to equipment in the zero-gravity environment of space. Additionally, foods that have strong odors are usually avoided to prevent the spread of smells in the confined space of a spacecraft.
because there was no space left in the aircraft...
No, astronauts do not take off their helmets to eat. Astronauts do not normally wear their helmets except when exposed to the vacuum of space. They are not normally exposed to space when in a spacecraft (Apollo, Skylab, Shuttle, Space Station, etc.). They eat while in the spacecraft, so there is no need to remove their helmets.
People eat food in space which is giving them energy. Nutritious food full of vitamin is only there.