It looked like a giant butterfly fl uttering through space, the wings of its solar panels extended to gather in the power from the sun’s rays. Different instruments attached at strange angles gave it an awkward and fragile look. But it was strong—strong enough to survive as it sailed silently across the frigid, bleak, black expanse of open space.

With each second it left Earth farther and farther behind. But attached to the satellite was a small part of its planet of origin, a gold disc showing a diagram of our solar system and an illustration of a man and a woman with their hands open in a gesture of friendship. No one could hope to predict, but maybe, just maybe, this wanderer might someday meet somebody in its travels.

First it travelled toward the giant of the solar system, the planet Jupiter. The journey of 759 million kilometres took nearly three years. Arcing into a perfect elliptical orbit above the poisonous atmosphere, it began its task. The lifeless satellite bristled with activity as it observed, recorded, analyzed, and transmitted information. Never before had man observed this mysterious planet at such close range. With this job completed the satellite was ordered out of orbit. Using its booster rockets and the gravity of the planet, it was slingshot farther out toward the more distant planets at the very edge of the solar system.

It was connected to Earth by a continuous trickle of information, like the string on a kite. Travelling at 300,000 kilometres per second, the signals raced back to Earth as the satellite continued on its relentless journey. With each passing hour it moved a further 17,000 kilometres away from Earth, and to places never before visited by man or his instruments. Six years after leaving Jupiter, having made close passes of five different planets, it passed beyond the outermost orbit of the outermost planet. In breaking this imaginary line, it left behind the solar system of its birth, but it refused to die. It kept travelling, kept recording, kept transmitting.

No one could have believed that despite the passing of eleven years and more than 24 billion kilometres, the satellite still had the will to live. As it rocketed farther and farther it continued to send back its messages: a faint, feeble voice coming from somewhere out there. Like a little lost child in the dark night sky, it called out, “I’m here. I’m still here.”

The scientists who had dreamed and conceived and then watched the life of the satellite would have marvelled at its continued existence. But the country that had sent this satellite skyward, the Soviet Union, no longer existed. It had been broken into smaller pieces, none of which now had the will or the resources to track the ongoing journey away from our solar system. The satellite called out, “Look at this!” but nobody was there to hear.

Thirty-three years after its launch, twenty-two years after it left our solar system, the satellite cruised toward a small planetary body. With the gentle pull of gravity it settled into a perfect orbit. This new home was a lifeless chunk of rock with a diameter of 500 kilometres, roughly one-sixth the diameter of Earth’s moon. This became the centre of the satellite’s universe as it sailed around and around and around, once every fourteen hours. And like the good machine that it was, it started to observe, record, analyze, and transmit its findings.

Just by chance, somebody was listening. The satellite transmitted its messages in its only true language, the language of mathematics. Its faint signals were accidentally heard and translated.

At first nobody thought it could be possible that the traveller still existed. This was cause for great celebration. With each orbit, at fourteen-hour intervals, as it faced toward Earth, it sent back information. But the messages didn’t seem to make sense. Somehow the satellite appeared to be moving closer. Somehow the world that it was attached to was moving closer. And the one message that the satellite wasn’t transmitting was the most important—perhaps the most important message in the history of mankind.

“I’m coming back, I’m coming home . . . and I’m not coming alone.”