On Wednesday morning, November 18, at 2:16 a.m. Pacific time, a spacecraft built in Pasadena passes a mark no human-made object has ever reached: Voyager 1 will be one full light-day from Earth, about 16.1 billion miles away. A radio signal will need 24 hours to get there; the reply, another 24 hours to come home.
It took 49 years, two months and 11 days. Launched September 5, 1977, Voyager 1 flew past Jupiter and Saturn, crossed into interstellar space in 2012, and it is still talking to the people who sent it — from a spacecraft run by NASA’s Jet Propulsion Laboratory, managed by Caltech in Pasadena.
What one light-day means
A light-day is a distance, not a length of time: how far light travels in 24 hours — 16,094,799,096 miles (25,902,068,356 kilometers), about 173 times the distance from Earth to the Sun. Voyager 1 is traveling at about 38,000 miles per hour.
Nothing on board will change when it crosses the mark — NASA is blunt about that. The milestone is a human one. As project manager Suzanne Dodd put it, “If you want to say ‘hello’ to Voyager, you send your message and then you go home and you wait two days before you finally get a response.”
How Pasadena can take part
NASA marks the week with two public events, both run through JPL.
On Tuesday, November 17, after sunset, NASA invites people everywhere to join “Shine Bright for Voyager’s Light-Day”: point a phone, a flashlight or a porch light at the sky and flash “VGR,” Voyager’s call sign, in Morse code. NASA built a page that flashes the code for you at go.nasa.gov/shinebright. Your flashlight will not reach the spacecraft — NASA calls the act symbolic, and that is the point.
Then on Thursday, November 19, at 9 a.m. Pacific, JPL hosts a moderated discussion in its von Kármán Auditorium, the hall that hosted Voyager briefings during the grand tour of the outer planets. The panel — Nicky Fox, who runs NASA’s science missions; JPL chief scientist Jonathan Lunine; Dodd; mission manager Kareem Badaruddin; and deputy project scientist Jamie Rankin of Princeton — will cover the status of both Voyagers, followed by questions and a preview of a NASA+ Voyager documentary planned for 2027, the mission’s 50th anniversary year. It streams live at nasa.gov/live.
Still flying on borrowed power
The milestone comes right after a reminder of how fragile this mission is. In early September, JPL engineers finished a months-long effort nicknamed the “Big Bang,” switching off three devices on Voyager 1 and substituting lower-power alternatives to stretch a power supply that loses about 4 watts a year. Without it, NASA says another instrument would have had to be turned off as early as summer 2027.
Then on October 18 and 19, NASA’s Deep Space Network could not detect Voyager 1’s signal during two scheduled contacts a day apart. The signal reappeared on October 20; engineers found one group of thrusters had gone offline and the backups had switched on. The cause is still under investigation. “This is the first time we’ve seen the spacecraft do something like this, but we are also at a point in the mission where we have to expect the unexpected,” Badaruddin said.
That is the honest context for next week’s celebration: a 1977 machine, built for a flyby of two planets, running on fading power and backup thrusters, still sending science home from beyond the edge of the solar system — and still operated from Pasadena. It also carries the Golden Record, with greetings in 55 languages, music and images from Earth.
Its cameras took one last look home on February 14, 1990: the Pale Blue Dot, Earth as a crescent 0.12 pixels wide in a band of scattered sunlight, photographed from more than 4 billion miles away. The cameras were switched off after that portrait. The spacecraft has been flying blind ever since — and it has never stopped talking.
So Tuesday night, step outside and flash VGR. Thursday morning, watch the discussion from JPL. A machine Pasadena built is about to be a full day of light from home, and it is still answering.
Sources: NASA news release M26-086 (Nov. 10, 2026); NASA Science, “Voyager 1: What Is a Light-Day” and “NASA’s Voyager 1 Conserves Power, Resolves Brief Communications Pause” (Oct. 29, 2026); NASA/JPL-Caltech photo PIA23645, the reprocessed “Pale Blue Dot” (public domain).
