NASA - National Aeronautics and Space Administration

Image above: The Skylab 4 command module upside down following splashdown on Feb. 8, 1974. NASA photo.

A little-known fact of the Apollo, Skylab and Apollo-Soyuz missions is that, upon splashdown, the space capsules rolled upside down in the ocean during about half of the landings.

Talk about hanging around! Astronauts hung safely, face-down, in their seat harnesses as round, balloon-like devices called righting spheres were inflated to roll the capsules back over.

The spheres, part of the spacecraft's uprighting system, were attached at the top portion of the capsules. The compressor-inflated balloons were designed to flip the capsules upright in the event of either landing upside down, or rolling over after landing in the sea. Obviously, designers expected such events, as this system was installed on all the command modules.

Upon returning to earth, the spacecraft parachuted to a splashdown upright on the broad heat-shielded base, lowered gently by three huge 'chutes.

Image above: ASTP capsule after sphere inflation and righting following splashdown on July 24, 1975. The flotation ring attached around the base of the capsule is also visible. NASA photo.

But, in rougher seas, or if the wind caught the parachutes as they floated to the surface, the capsules rolled or were dragged over.

When that happened, the command module pilot would flip a switch to deploy the righting spheres and start compressor fans to inflate them.

Astronaut Vance Brand, NASA Dryden Flight Research Center's deputy director of aerospace programs, is a veteran of three space shuttle missions as well as the Apollo-Soyuz Test Program (ASTP) mission in 1975. That was the last flight of an Apollo-type spacecraft, and America wouldn't venture into space for the next six years while the space shuttle was being developed.

Brand served as command module pilot for the Apollo-Soyuz flight, and he remembers his post-splashdown rollover experience well.

"Rolling upside down felt like slow motion. We hadn't transitioned back to gravity yet after being weightless in space, so it felt a little awkward hanging in the straps," Brand remembers. "The balloon deployment system was activated, and then we hung there for what seemed like minutes as the balloons inflated before rolling gently back over."

Image above: The righting spheres on the Apollo 13 capsule are clearly visible as the capsule is was photographed being hoisted aboard the U.S.S. Iwo Jima on Apr. 17, 1970. NASA photo.

Once the spheres inflated, they caused the apex, the pointy-ended top of the spacecraft, to rise above the ocean's surface, allowing gravity to pull the heavier bottom downward.

Each time they were needed, the system worked properly, righting the capsules.

After the spacecraft righted itself, U.S. Navy divers attached a flotation ring or collar around the base of the craft, further stabilizing it.

Astronauts practiced for rollovers as part of their water egress training.

"Just in case the balloon system failed, and we had to get out of an upside down capsule floating in the water, we practiced egressing through the docking ring rather than the hatch in an upside-down attitude. We had to go down to get out and swim up to the surface," Brand added.

"It wasn't a bad way to land, aside from the complications of needing Navy ships on hand for support," Brand said.

Gray Creech
NASA's Dryden Flight Research Center