Do Astronauts Eat Sandwiches?

Sure, they do! It's called a "rocket science sandwich!"

But first, a quick question: "Have you ever dropped a few crumbs while making or eating a sandwich?" Well, you can't do that in space because in zero gravity astronauts accidentally could inhale breadcrumbs floating around in their spacecraft and choke. That's why lunch on the Space Shuttle is served on special "space bread," a tortilla-like wafer that snaps instead of crumbles. To create it, NASA's food scientists used nuclear magnetic resonance (NMR), known as "MRI" in medical testing, to study bread at the atomic level.

Lindstrom, Elizabeth E. (Editor). Odyssey: Adventures in Science. 2009: 18 (3); p. 15.