You're looking at the three Apollo 11 astronauts, plus a member of the recovery team, all clad in their BIGS after the astronauts were extracted from the command module.

Image courtesy NASA/Newsmakers

Alien Microbes Not Welcome: Reducing Back Contamination on Apollo 11

When NASA set its sights on the moon in the 1960s, no one knew if lunar dust held exotic life forms or not. What if a nasty bug lived on our nearest celestial neighbor? And what if said bug made it back to Earth and upset the planet's delicate ecological balance? These weren't just concerns of the U.S. space program. Nope, author Michael Crichton posed them, too.

In May 1969, just two months before Apollo 11 would carry the first humans to walk on another celestial body, Crichton published "The Andromeda Strain," a cautionary tale about dangerous microorganisms carried to Earth on a spacecraft. The best-seller ignited fears about the consequences of a space mission contaminating our planet. NASA, of course, had already worked hard to develop stringent planetary protection guidelines by then, but it redoubled its efforts to help soothe public concerns.

Like we talked about, NASA ultimately would deem the moon incapable of supporting life and ease its planetary protection guidelines around lunar missions, but the early Apollo program, especially Apollo 11, models how the space agency has minimized previous back contamination risks. NASA's approach addressed three main concerns: the returning spacecraft, the astronauts and any samples carried back. Let's start with the astronauts.

When the Columbia Command Module splashed down in the Pacific Ocean on July 24, 1969, a recovery crew jumped from a helicopter to the floating spacecraft. After attaching a flotation collar to the craft and inflating rafts, one of the crew members opened the hatch to the module, passed over three biological isolation garments (BIGs) and quickly resealed the hatch. This crew member also wore one of the suits to prevent contamination during the hand-off.

Once the astronauts sealed themselves safely within their protective garments, the command module hatch was reopened, and they climbed aboard one of the rafts. All three astronauts received a bleach-based sponge bath and then waited as the member of the recovery crew wiped down the hatch and the exhaust vents of the command module with iodine solution. Then the people on the helicopter hoisted the astronauts out of the water and carried them to the deck of the USS Hornet. After an elevator ride down to lower decks, they exited and walked to the mobile quarantine facility (MQF), a sealed chamber that would be their home for several days.

The ship transported the facility, with the Apollo crew sealed inside, to Honolulu. Then an airplane carried it to Houston, where a waiting truck whisked the astronauts to the Lunar Receiving Laboratory, or LRL. On July 27, the astronauts walked from the MQF through a sealed tunnel into the lab's crew reception area. The astronauts remained under quarantine in Houston until Aug. 10, while a team of doctors monitored their health and watched for possible infections. When none developed, they were deemed healthy and free of lunar pathogens.