In 1985, two famous soda companies sent special cans into space on the Space Shuttle. People later called it the "space cola war."

But the astronauts did not like the drinks very much. There was no refrigerator, so the drinks were warm. They were also too foamy. On Earth, bubbles in soda go up to the top. In space, they stay mixed in the drink.

In July 1985, two well-known soda companies sent specially designed cans into space on the Space Shuttle Challenger. This event later became known as the "space cola war."

Normal cans would not work, because the drink might shoot out or refuse to come out at all. According to the Smithsonian, however, the astronauts were not impressed. The shuttle had no refrigerator, so the drinks were warm, and both were far too foamy.

Neither drink was added to NASA's official menu. The reason lies in physics. On Earth, bubbles rise because of buoyancy. In weightlessness, there is no buoyancy, so bubbles stay mixed in the liquid instead of separating from it.

In July 1985, the Space Shuttle Challenger's STS-51F mission carried an unusual cargo: specially engineered cans from two rival soft-drink companies, an episode later nicknamed the "space cola war." Ordinary cans were unsuitable because, without gravity, the contents might spray out or fail to emerge. According to the Smithsonian's National Air and Space Museum, the crew's verdict was unenthusiastic.

With no refrigerator aboard, the drinks were warm and both turned excessively foamy; carbon dioxide dissolves less readily at higher temperatures, which may have added to the problem. Neither was adopted for NASA's standard menu, although one flown can is now in the museum's collection. The underlying problem is basic physics. On Earth, bubbles rise because buoyancy pushes the lighter gas upward through the denser liquid, so gas and liquid separate.

In microgravity, buoyancy effectively disappears, and bubbles remain dispersed in the liquid. The same issue may continue inside the body: because gas and liquid do not separate well in the stomach, burping can bring up liquid as well, though this is rarely studied. Cans do not explode, since the cabin is kept at nearly normal air pressure. Separating gas from liquid also matters for fuel tanks and water recycling.