When March 2, 1972, the Atlas-Centaur launch vehicle lifted Pioneer 10 into the sky, the spacecraft carried the first artifact in human history intended for an encounter with intelligence beyond the Solar System—and the first scandal that forced NASA to explain itself to Congress over "interstellar striptease."
🚀 The idea was born over lunch. Eric Burgess, a British science journalist, suggested to Carl Sagan in 1971: if Pioneer 10 was to become the first spacecraft to escape the Sun’s gravitational dominion, why not equip it with a message? Sagan seized the idea instantly—NASA had just three weeks to design, fabricate, and install the plaque before launch. Time was tight: the probe was already undergoing final tests at Cape Canaveral, and engineers demanded precise specifications for mounting any additional payload to the antenna support. Frank Drake, an astronomer at Cornell University and a pioneer of the SETI program, took on the mathematical portion of the message—a map of Earth’s position relative to fourteen pulsars, whose unique emission periods served as cosmic beacons. The artistic execution fell to Linda Salzman Sagan, Carl’s wife and a professional artist.
🎨 The plaque, made of anodized aluminum measuring 23×15 centimeters with a gold coating a few microns thick, was designed to withstand an interstellar journey lasting millions of years: cosmic dust striking at speeds of tens of kilometers per second, temperature swings from minus two hundred to plus one hundred degrees Celsius when passing near stars, and a barrage of high-energy particles. The gold coating wasn’t an aesthetic choice but an engineering necessity—the metal doesn’t oxidize, reflects ultraviolet light, and preserves the engraving under the proton bombardment of the solar wind. Precision Engravers of San Carlos, California, completed the etching in four days—a record time for precision work of this scale. Linda Salzman drew the human silhouettes by referencing classical Greek sculptures and anatomical atlases: the body proportions adhered to the idealized canon of Polykleitos, the male figure standing 175 centimeters tall, the female 165. The man raised his right hand in a gesture of greeting—universal, the creators hoped, as a signal of peaceful intent and a demonstration of limb mobility.
🔬 The decision to depict humans nude was an engineering choice, not an ideological one. Clothing is a cultural code, shifting every decade: the ancient Roman toga, the medieval doublet, the Victorian corset, the 1970s jeans—each era dictates its own form. For a civilization separated from humanity by millions of years of evolution, attire would be as meaningless an artifact as a peacock’s feathers for describing avian anatomy. Sagan insisted: the body is the only constant, a biological fact independent of fashion. But even within this logic, concessions had to be made: the female genitalia were absent from the final version of the plaque—the vulva line was erased at NASA’s behest before design approval. The male genitalia remained, but in schematic form, without detail. This wasn’t censorship for decency’s sake—NASA feared accusations of pornography before the spacecraft even left the atmosphere.
⚖️ Racial representation became the team’s second headache. The figures were conceived as "pan-racial"—facial features were smoothed, devoid of pronounced Europoid, Negroid, or Mongoloid traits. The man’s hair was wavy and medium-length, his nose straight, his lips of average fullness. The woman was depicted with short hair and a neutral profile. But the plan backfired: representatives of African American communities pointed out that the figures looked "too white," Asian critics noted the Europoid proportions of the skull, while Europeans saw them as averaged Mediterranean types. Linda Salzman later admitted: the female figure was partially modeled after herself, the male a composite based on ancient statues. The silhouettes turned out static, like anatomical mannequins from a textbook, not living people—this was a conscious choice to minimize cultural specificity in gestures and expressions.
📐 The pulsar diagram, engraved to the left of the figures, consisted of fourteen lines radiating from a single point—the Sun’s position. The length of each line encoded the distance to a pulsar, while binary numbers along the lines represented their rotation periods, measured in units of 0.704 nanoseconds (the period of the hydrogen atom’s hyperfine transition—the most abundant element in the universe). Drake understood: any advanced civilization would know hydrogen, and pulsars are visible across interstellar distances. But the scheme required knowledge of binary notation, astronomy, nuclear physics, and deductive reasoning—a barrier that, skeptics argued, would render the message unreadable for most potential recipients. At the bottom of the plaque was a diagram of the Solar System, with the third planet highlighted and the trajectory of Pioneer 10 launching from Jupiter. The entire design adhered to the logic of scientific infographics, but the choice of symbols—the human silhouettes—turned a technical diagram into a cultural statement.
📰 The publication of the plaque’s image in the press spring of 1972 provoked a reaction NASA hadn’t anticipated. The Los Angeles Times ran a version with censorious black bars covering the genitalia, while the Chicago Sun-Times headlined its piece "Interstellar Striptease." An editorial asked: "Are taxpayers funding the dispatch of obscenities into space?" Sagan received hundreds of letters—some are preserved in the Library of Congress archives, declassified in the 1990s. A typical missive read: "Professor Sagan, you’re disgracing the nation. If aliens see that we’re sending them naked people, they’ll think Earth is a planet of savages." Another correspondent suggested "dressing the figures in formal suits to show that humanity is a civilized species." A third demanded the figures be depicted in prayerful poses, "to convey our faith in God."
🚺 Feminist criticism struck from another flank. Gloria Steinem, founder of Ms. magazine, wrote in 1972: "NASA’s message broadcasts patriarchal stereotypes: the man is active, greeting, acting; the woman is passive, standing by, silent. This isn’t a representation of humanity—it’s an advertisement for male supremacy in space." Feminist organizations pointed to the symbolic hierarchy: the man’s raised hand—a gesture of power and initiative—versus the woman’s lowered arms—submission. The man stood half a step ahead, the woman to the side and slightly behind, like an accompanying figure, not an equal partner. Even the erased vulva line was seen as censorship of female sexuality while preserving male anatomy—an asymmetry reflecting terrestrial taboos. Sagan responded: "The greeting gesture isn’t a display of power but a signal of communication. We’re not broadcasting gender roles—we’re showing joint mobility." But the arguments didn’t land: critics saw the plaque not as a scientific diagram but as a cultural declaration, and they argued precisely with the latter.
🏛️ Congress didn’t stay on the sidelines. At hearings before the Committee on Science and Technology, a NASA representative was forced to explain that the plaque wasn’t state ideology but an attempt to convey basic information about Homo sapiens. A senator from Mississippi declared: "If we’re sending a message on behalf of America, it should reflect our values, not shock our allies and enemies." Another lawmaker demanded guarantees that future missions would undergo public discussion of message designs. Sagan wrote in private correspondence: "We created the first artifact designed to outlast the civilization that made it, and the first thing humanity did was spark a scandal over two schematic silhouettes." The plaque became a battleground between scientific universalism and cultural specificity: physicists believed mathematics and anatomy were common languages, while sociologists countered that any choice of imagery was a political act.
🎵 When Voyager 1 and 2 were being prepared for launch in 1977, NASA had learned its lesson. Instead of an engraved plaque, the spacecraft carried gold-plated copper phonograph records with recordings of Earth sounds, music, and 116 images encoded in analog format. Sagan again oversaw the idea, but the team expanded to include anthropologists, linguists, and sociologists. This time, the human images were clothed: photographs of families in national costumes, snapshots from different cultures and eras. Instead of a nude couple, there was a silhouette of a pregnant woman and a man holding hands—schematic and delicate. A separate diagram of vertebrate evolution included anatomically correct nude figures of a man and woman, where the woman raised her hand while the man stood neutrally—a symbolic inversion of the criticized pose from the Pioneer plaque.
🌍 But the compromise sparked new debates. Defenders of the original design argued that clothing made the message culturally specific, tied to the 20th century and particular regions of Earth. Kimonos, saris, jeans—artifacts of specific societies, not universal markers of the species. Family photographs depicted social constructs—monogamy, the nuclear family, gender roles—that might not exist for the recipients. Sagan defended the choice: "We’re not sending an ideal but reality. Humanity in 1977 wears clothes, lives in families, creates music. This is an honest snapshot of the moment, not a timeless abstraction." Nevertheless, NASA’s committee on the Voyager record’s content rejected a proposed photograph of a nude pregnant couple—too risky after the Pioneer scandal. The only nude figures on the record appeared as silhouettes on a diagram—abstract enough to avoid another wave of criticism.
📌 Today, both Pioneer plaques and the Voyager records are hurtling in different directions across the galaxy. Pioneer 10 last made contact on January 23, 2003, at a distance of 12.2 billion kilometers from the Sun; its signal faded beyond Pluto’s orbit. Voyager 1, in August 2012, became the first human-made object to cross the heliopause—the boundary where the solar wind yields to interstellar space—and continues to transmit data, receding at 17 kilometers per second. The nearest star on Pioneer 10’s trajectory is Aldebaran in the constellation Taurus, which the spacecraft will reach in two million years. By then, the civilization that launched it may have long vanished, while the plaque remains—an archaeological artifact of a species that tried to explain itself to the cosmos.
📡 The debates over representing humanity haven’t subsided. The Breakthrough Message project, launched in 2015 by Yuri Milner and Stephen Hawking with a $1 million prize fund, calls for the creation of a new interstellar message—but one that is public, crowdsourced, and globally discussed. Critics remind us: sending a signal into space is an act on behalf of the entire planet, and no single group of scientists or government has the right to unilaterally decide what to say. Others counter: democracy in messaging is a utopia, consensus is unattainable, and while humanity argues, the window of opportunity closes. China’s FAST program, the world’s largest radio telescope with a 500-meter diameter, is considering actively transmitting signals to nearby exoplanets, but Beijing hasn’t disclosed what message it plans to send. Meanwhile, the golden plaque of Pioneer 10 continues its journey, bearing humanity’s first calling card—naked, controversial, slipping into the darkness at third cosmic velocity, a silent testament to the fact that our species couldn’t even agree on two silhouettes.