Following its trip to the Moon and back, NASA’s Orion spacecraft splashed down into the Pacific Ocean on Sunday. The inaugural flight for the Artemis program may have been uncrewed, but Orion carried five souvenirs to honor a legacy of lunar exploration.

NASA has a longstanding tradition of stashing hidden messages and mementos on board its spacecraft. In 1977, Voyager 1 and Voyager 2 launched to interstellar space carrying a 12-inch gold-plated copper disk known as The Golden Record. The phonograph record included various images and sounds that represent life on Earth in case it is ever found by spacefaring aliens. More recently, NASA engineers encoded a binary message on the Perseverance rover’s parachute that read, “Dare Mighty Things.”

For the Artemis 1 mission to the Moon, NASA stuck to a lunar theme. The Orion capsule had five hidden messages placed around the crew cabin, NASA revealed in a press release on Saturday.

Binary code

Binary code for the number 18 was place on the top of the pilot’s seat as a tribute to NASA’s Apollo program. On December 11, 1972, the Apollo 17 mission touched down on the Moon, marking the last time astronauts walked on the lunar surface.

With the Artemis program, NASA is hoping to land humans on the Moon as part of the Artemis 3 mission set to take place no earlier than 2025. The number 18 symbolizes a human spacecraft’s return to the Moon following Apollo 17.

Fly me to the Moon

On the right side of the Orion spacecraft, the letters CBAGF are written below one of the windows. The letters symbolize Frank Sinatra’s song, “Fly Me to the Moon,” representing the musical notes of the familiar tune.

A tribute cardinal

NASA placed an image of a cardinal above the window to the right of Orion’s pilot seat as a tribute to Mark Geyer, former Orion program manager, who died in 2021. Geyer was a devout St. Louis Cardinals fan, according to NASA.

Code for Charlie

The space agency also paid tribute to the life of former Orion Deputy Program Manager Charlie Lundquist, who died in 2020.

NASA included the morse code for “Charlie” to recognize the role that Lundquist played in the development of Orion.

European cooperation

NASA recognized the cooperation of its partners from the European Space Agency who developed the service module for the Orion spacecraft.

In front of the pilot’s seat, the space agency included the country codes of each country that took part in developing the spacecraft, including; the United States, Germany, Italy, Switzerland, France, Belgium, Sweden, Denmark, Norway, Spain, and The Netherlands.

More: Orion Splashes Down in Pacific, Ending NASA’s Historic Artemis 1 Moon Mission