An area of a space vehicle considered to be a floor, although ‘up’ and ‘down’ are uncertain orientations in space. To help astronauts determine ‘down’, space vehicles have their decks painted in a darker colour than their ceilings. A space shuttle was flown by its pilot and commander from the flight deck, which also had seats for two more crew members. Below the flight deck was the mid-deck, providing room for three additional crew members and was used for sleeping, food preparation, and storage. The lower deck was an equipment and stowage area.

‘Deck’ was taken from the naval term for a ship's floor.