NASA’s Europa Clipper is launching in October, and it’s set to unveil the secrets of one of the most intriguing celestial bodies in our solar system. Coming along for the ride is a commemorative plate that symbolizes humanity’s fascination with Jupiter’s mysterious moon Europa and our relentless quest to find extraterrestrial life.
Europa represents a fascinating target. The Jovian moon is of huge interest to scientists, primarily due to its suspected ocean, lying beneath a thick crust of ice. This hidden ocean is not just captivating as a geological phenomenon—it might host life. By exploring this moon, the Europa Clipper aims to deepen our understanding of these mysteries, enhancing our knowledge about the potential for biology beyond Earth.
Following its 1.6-billion-mile (2.6-billion-kilometer) journey, Europa Clipper will perform 49 close flybys of Europa to study its subsurface ocean, icy crust, thin atmosphere, and space environment. A protective metal vault hosts the spacecraft’s scientific instruments, shielding them from Jupiter’s harsh radiation. Last week, NASA provided details about a triangular metal panel that seals the opening to this vault, which doubles as a commemorative plate.
NASA has a history of sending messages into space, beginning with the Pioneer plaques and the Voyager Golden Records, which were designed to communicate the story of our world to intelligent alien life. The “Message in a Bottle” on the Europa Clipper mission is a continuation of this practice. However, unlike previous messages that were sent on an interstellar trajectory, this message will remain within our solar system.
The plate, crafted from tantalum and measuring around 7 by 11 inches (18 by 28 centimeters), features graphics and text on both sides. The available surface area hosts five unique elements: a poem, a portrait of a scientist, the outline of a bottle, and two SETI-related messages, namely the famous Drake Equation and “water hole” emissions, which refer to a specific range of radio frequencies thought to be ideal for interstellar communication due to their low background noise.
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The exterior portion of the plate displays graphics that emphasize humanity’s connection to Europa, featuring recordings of the word “water” spoken in 103 languages (you can listen to them here); audio recordings were transformed into visual waveforms, which were then etched onto the plate. A symbol for “water” in American Sign Language appears at the center. “The message of connection through water, essential for all forms of life as we know it, perfectly illustrates Earth’s tie to this mysterious ocean world we are setting out to explore,” Lori Glaze, director of the Planetary Science Division at NASA Headquarters in Washington, said in a NASA statement.
To assist with the project, NASA recruited METI International, a non-profit that contributes research into the design and transmission of interstellar messages in the hopes of making contact with alien civilizations (METI stands for Messages to Extraterrestrial Intelligence). Douglas Vakoch, the founder and president of METI, said his group was initially brought on to determine the appropriate languages to feature in the “water words” segment of the message. With three linguists on METI’s board of directors, it was a good fit.
“That was a natural match,” Vakoch explained in an email. “METI’s earliest contribution to the project draws on the science of linguistics, which identifies the major families of languages on Earth. This let us identify a broadly representative sampling of languages to feature on the message plate.”
The outer part of the plate will eventually feature a silicon microchip, which has been etched with the names of over 2.6 million individuals who submitted their names to NASA.
As for the interior portion, it features an engraving of U.S. Poet Laureate Ada Limón’s handwritten poem, “In Praise of Mystery: A Poem for Europa,” and a portrait of Ron Greely, a pioneer in planetary science. NASA credits Greely’s initial endeavors in developing a Europa mission two decades ago as the foundational work that led to the Europa Clipper project.
Unlike the messages aboard the Pioneer and Voyager probes, this latest project resembles a time capsule and reflects our unending curiosity; it’s meant for us, and not aliens. But as Vakoch explained, comprehension of of the “Message in a Bottle” could wane over extreme timeframes.
“The more we developed the various parts of the message to be attached to the Europa Clipper, the clearer it became that none of these could be interpreted if they were discovered by someone who wasn’t already familiar with the contents,” Vakoch said. “The Drake Equation wouldn’t make sense unless someone already knows what each of the terms stands for, and the poem would be intelligible only to a reader of English.” The Drake Equation is a formula used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy.
The Europa Clipper, built by NASA’s Jet Propulsion Laboratory, is most likely to meet its end by burning up during a planned atmospheric entry, according to Vakoch. However, should the mission deviate and the spacecraft survives, future humans from a radically different culture might find it challenging to interpret images like a bottle and a scientist’s portrait, should they come across this artifact millennia later, he explained.
That said, the plate includes radio frequencies considered plausible for interstellar communication; these are specifically frequencies that align with radio waves emitted in space by water components, a range referred to by SETI scientists as the “water hole.” These frequencies “are labeled with images that depict electrons as points located within orbital shells,” said Vakoch. “The hope is that even chemists of future generations will recognize these elements.”
The waveforms on the vault plate serve as a common element, he added. On one side, over a hundred words for “water” are represented by their unique waveforms, while on the reverse side, the plate features etchings of two specific waveforms: those of hydrogen and hydroxyl, the basic components of water. “These wavelengths also correspond to the wavelengths of radio emission lines that mark the frequencies astronomers have used to guide the search for signals from other civilizations,” Vakoch explained.
Europa Clipper, with its fancy commemorative plate, is scheduled to launch in October aboard a SpaceX Falcon Heavy rocket. The spacecraft will arrive at Europa in April 2030 after a 5.5-year journey, and then spend the better part of four years performing its scientific duties. With the commemorative plate on board, Europa Clipper transcends a mere scientific mission—it will also serve as a symbolic ambassador of humanity, bridging the gap between art, culture, and space exploration.
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