Why Astronauts Wear Bright Orange Suits: The Important Function

The safety and survival of astronauts during the most volatile phases of spaceflight depend on highly specialized equipment designed to mitigate extreme risks. For the Artemis II mission, NASA engineers have developed the Orion Crew Survival System (OCSS), a high-visibility flight suit designed specifically for launch and entry.

The most striking feature of the OCSS is its bright orange color, often referred to as international orange. This specific hue is chosen for its high visibility, a critical safety requirement for astronauts who may need to be located quickly in the ocean following a return-to-Earth splashdown.

The Science of Visibility and Survival

The selection of international orange is based on the need for the suits to stand out against the ocean. This color choice is common in aerospace and marine industries for similar reasons; for example, the Golden Gate Bridge uses a similar color to remain visible against bay fog.

The OCSS is not intended for spacewalks or moonwalking, but rather as a critical life-support system for emergencies. The suits are engineered to keep astronauts alive for up to six days, or 144 hours, even in the event that the Orion spacecraft loses cabin pressure while in space.

To further ensure survival during a water landing, each suit is equipped with a personal life preserver. This survival gear includes several specialized tools:

• A personal locator beacon
• A rescue knife
• A signaling kit containing a mirror, strobe light, flashlight, whistle, and light sticks

Evolution of Astronaut Flight Suits

The use of orange for launch and entry is a modern standard that evolved from earlier, varied approaches to astronaut apparel. During the Mercury program, astronauts wore reflective silver suits. From the Gemini program through Skylab, the standard color was white.

The early Space Shuttle missions, specifically STS-1 through STS-4 between 1981 and 1982, utilized suits that were a dull brownish yellow or mustard color. The transition to the bright orange suits occurred after the Challenger disaster in 1986, as visibility during rescue operations became a paramount priority.

Historically, the requirements for suits have shifted from multi-purpose gear to specialized systems. In the early days of spaceflight, such as with Soviet cosmonaut Aleksei Leonov in 1965, a single suit was used for both launch and extravehicular activity (EVA). The Apollo program also utilized the A7-L suit as a multi-purpose garment for launch, Moon surface activities, and landing, though command module pilots wore slightly different gear.

By the Shuttle era, a clear distinction was made between training and flight. Astronauts trained in blue suits but flew in the orange suits during actual missions.

Modern Engineering in the OCSS

The Orion Crew Survival System represents a modern reinvention of the pumpkin suits used during the Space Shuttle era. While they may appear similar, the OCSS has been enhanced from head to toe with improvements over previous shuttle mission suits.

Each suit is custom-made to the specific physique of the astronaut by NASA engineers. Every element of the garment, including the seams, stitches, zips, and pockets, is expertly planned to serve a specific purpose, prioritizing safety and functionality in the harsh environment of deep space and the critical moments of reentry.