Space food. Packets of food used by astronauts during the Mercury space missions. The ruler at bottom shows the scale. The food was dried to prevent spoilage and to cut down on preparation. Some of this food required rehydration with a water gun, but some (in bite-sized pieces at upper centre) was ready to eat. Despite the convenience of such foods, they were widely criticised by the astronauts themselves. The Mercury missions were the first to place an American astronaut in space (Alan Shepard, 1961) and later, in orbit (John Glenn, 1962).