NASA is inviting people around the world to mark a distance no human made object has ever reached. Voyager 1 is set to become the first spacecraft to sit one light-day from Earth on Wednesday, November 18, 2026.

The milestone means light traveling from Earth would need an entire day to reach the spacecraft. NASA plans to recognize that extraordinary separation with a worldwide celebration involving flashlights, glow sticks, smartphones, and Morse code.

The event, called “Shine Bright for Voyager’s Light-Day,” is scheduled for Tuesday, November 17. It will take place one day before the milestone because any message sent from Earth would then need at least 24 hours to travel to Voyager 1.

Participants are being asked to point a flashlight, glow stick, or smartphone toward the sky. They can then flash the spacecraft’s call sign, “V, G, R,” using Morse code as part of the shared tribute.

NASA has also created an automated player that spells out the code for participants. The instructions for the letter R call for “One quick flash, one long flash, one quick flash.”

The display will not function as an actual signal to Voyager 1. Only an incredibly small fraction of the photons produced on Earth would ever travel anywhere near the distant spacecraft, and Voyager 1 has no way to detect the display.

Light from a flashlight or smartphone screen spreads as it moves outward. By the time such a beam traveled one light-day, it would be far too diffuse for anyone aboard Voyager, if anyone were there, to detect.

NASA is therefore presenting the event as a “symbolic wave” rather than a practical attempt at communication. It is intended as a collective acknowledgment of the spacecraft and the immense distance it has covered.

“A simple act. A shared moment. A celebration of humanity’s farthest reach,” said NASA. The event transforms Voyager 1’s enormous separation from Earth into a moment people can recognize together from the ground.

One light-day is equivalent to 25.9 billion kilometers, or 15 billion miles, from Earth. At that distance, light traveling at 299,792,458 metres per second requires a full 24 hours to complete the journey.

Voyager 1 began its voyage in 1977 alongside its twin spacecraft, Voyager 2. Their journey included a tour through the Solar System past Jupiter and Saturn, as well as the Ice Giants, before Voyager 1 continued toward interstellar space.

In August 2012, Voyager 1 crossed the heliopause, the Sun’s surrounding magnetic and plasma bubble. That crossing made it the first human made object to enter interstellar space, adding another historic achievement to its mission.

The spacecraft’s more recent years have resembled a gradual retirement. NASA engineers have switched off numerous pieces of equipment aboard Voyager 1 and Voyager 2 during the past several years to conserve their remaining energy.

Despite relying on technology that is now about five decades old, both spacecraft remain operational. If all goes well, they are expected to stay within the range of the Deep Space Network until the 2030s, allowing Earth to communicate with them.

The Voyager mission’s legacy will continue even after communication with the spacecraft ends. Both are carrying Golden Records, gold plated phonograph records containing information intended to portray life on Earth through images and audio.

Those records present aspects of Earth’s life, science, and culture. They were conceived as messages in bottles cast into the cosmos, with the hope that extraterrestrial lifeforms might gain some understanding of humanity and the story of its planet.

The symbolic wave planned by NASA adds another earthly message, although this one cannot physically reach its intended recipient. It instead gives people around the world a way to celebrate Voyager 1 as it crosses a boundary measured not in miles alone, but in a full day of light.