Last September, the Times reported that Voyager 1, the hardy spacecraft launched in 1977, had exited the solar system and entered the interstellar void. Whenever stories about Voyager 1 and Voyager 2 appear in the papers, I read every word, transfixed: I was nine years old when the vessels began their journeys outward, and avidly followed news of their early progress. When, in 1981, I changed schools, a favorite teacher gave me a copy of Carl Sagan’s book “Murmurs of Earth,” which describes the Golden Record affixed to both Voyagers—a disk containing greetings, natural sounds, pictures, and music, intended to document human civilization for the possible benefit of extraterrestrial beings. To hear that Voyager 1 is now nineteen billion kilometres from Earth is a precise indicator of the aging process. At the same time, the craft’s longevity—it is expected to continue sending data until 2025—is vaguely encouraging. May we all transmit so reliably.

Recently, the composer Raphael Mostel told me that one of his colleagues, the composer, musician, and software engineer Laurie Spiegel, has intimate knowledge of the Golden Record and of the curious legal issues it raised. For a section of the disk titled “Sounds of Earth,” Sagan’s sonic team had chosen Spiegel’s piece “Harmonices Mundi.” Spiegel was given a contract to sign, a copy of which she kept in her files. When I asked about it, she kindly sent me a scan of the document, which will be of interest to specialists in the obscure and complex field of Space Copyright Law, and possibly a few connoisseurs of avant-garde legal language.

“Harmonices Mundi,” or “Harmony of the World,” is a realization of Johannes Kepler’s hypothesis that the motion of the planets can be translated into a “never-ending polyphonic music.” Using the GROOVE system (Generated Real-time Output Operations on Voltage-controlled Equipment), at Bell Telephone Laboratories, Spiegel converted orbital data into musical material, choosing the six planets known to Kepler: Mercury occupies the highest frequencies, Jupiter the lowest. In theory, the piece can go on indefinitely, but the Voyager cut lasts thirty-seven seconds. A ten-minute-and-forty-second version can be heard on Spiegel’s 1980 LP “The Expanding Universe,” which was reissued in 2012. Here is an excerpt:

The crucial clause in the Voyager contract is this:

Spiegel, when confronted by these sweeping phrases, decided that she wasn’t quite ready to surrender rights in the entirety of the known physical universe. Before signing, she crossed out the phrase “throughout the world and.” Therefore, to receive earthly permission for the excerpt above, I needed merely to ask Spiegel herself, and not the rights department at NASA. In any case, as a 2008 paper by J.A.L. Sterling demonstrates, the legal definition of extraterrestrial rights is far from clear. The Economist recently explored the question in relation to Chris Hadfield’s performance of David Bowie’s “Space Oddity” on board the International Space Station last year.

Of the composers and songwriters represented on the Golden Record—Bach, Beethoven, Stravinsky, Louis Armstrong, and various others—Spiegel and Chuck Berry are the only ones still living. I couldn’t reach Mr. Berry, but Spiegel supplied a few thoughts about what it’s like to have a work of hers wending its way into deep space. “I often think of those craft as sad and lonely,” she told me, “so very far from home, moving ever farther into the cold and the dark, sensing more and more hungrily for the slight, fading, low-level warmth of the increasingly dim sun. Yes, it is an amazing accomplishment for us humans, but it can also generate a feeling that a small part of us, the accumulated living habitation of this planet, has been propelled farther away from its home than anything ever should be. The rational part of my mind knows that I shouldn’t anthropomorphize, and see the Voyager as a being in exile or even as an extension of our own organic sensory systems. Possibly, my doing so is a carryover reaction from my horror and sadness when I learned of the Soviet dog, Laika, who died on the Muttnik (Sputnik 2) space mission that launched when I was twelve. We know all too well what a double-edged sword our technological and information-structuring brilliance can be.”

Sagan, in his lifetime, was often mocked as a dreamer, a fantasist, a fount of grandiose pronouncements. “Billions and billions,” Johnny Carson famously intoned. The Golden Record almost didn’t make it onto the Voyagers, as Timothy Ferris recounted in 2007; NASA feared that Congress would find the project ridiculous. As the years go by, and the ambitions of the Space Age fade, the Golden Record takes on a melancholy power. Sagan saw it as nothing less than a message in a bottle: “Billions of years from now our sun, then a distended red giant star, will have reduced Earth to a charred cinder. But the Voyager record will still be largely intact, in some other remote region of the Milky Way galaxy, preserving a murmur of an ancient civilization that once flourished—perhaps before moving on to greater deeds and other worlds—on the distant planet Earth.” Sagan takes an optimistic view of our far future, yet the strains of the Cavatina from Beethoven’s Opus 130 Quartet, which end the record, may strike the emotionally attuned extraterrestrial listener as a wistful farewell.