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2026-10-27

One Light-Day: A 1977 Machine Hits the Edge of a Day, the Night Before GTA 6

NASA's Voyager 1 spacecraft, launched from Cape Canaveral on September 5, 1977, will be exactly one light-day from Earth on Wednesday, November 18, 2026, at 2:16:07 a.m. Pacific, 5:16:07 a.m. in New York. That is 16.094 billion miles (25.902 billion kilometers), the distance light covers in 24 hours, according to NASA.

The next morning, Thursday, November 19, Grand Theft Auto VI comes out. One of the most anticipated pieces of software ever made, landing on consoles with hundreds of thousands of times the memory of Voyager's computers, the day after a box of 1970s electronics crosses a line no human-made object has crossed before.

If you say "hello" to Voyager 1 at the moment GTA 6 unlocks at midnight, it hears you around midnight the next night. If it answers, you hear back the night after that. And it still answers.

NASA line drawing of the Voyager spacecraft with labels for the 3.7-meter high-gain antenna, the science boom instruments, the magnetometer boom, the hydrazine thrusters and the three radioisotope thermoelectric generators
The blueprint: NASA/JPL's labeled drawing of the Voyager spacecraft, shown without its thermal blankets. The dish is 3.7 meters across; the long boom carries the magnetometer; the cylinders at bottom right are the nuclear power supplies. NASA/JPL, public domain.

What a light-day actually means

Light is the speed limit, and radio is light. Every message to Voyager 1 travels at 186,282 miles a second and still needs a full day to get there after November 18. A question and an answer is a two-day round trip. Nothing about that can be engineered away; it is the size of the solar system written in time.

For a sense of scale: the Moon is about 1.3 light-seconds away. The Sun is about 8 light-minutes. Voyager 1 is now about to be 1,440 light-minutes out, and it got there on a single shove from a Titan IIIE-Centaur rocket and two gravity assists, at Jupiter and Saturn, almost half a century ago.

One wrinkle: Earth goes around the Sun while Voyager heads away, so the distance between us wobbles a little through the year. November 18 is the first time the line gets crossed. Expect the occasional headline about Voyager "getting closer" as Earth swings back toward it; the long-term direction is out.

A Titan IIIE rocket lifting off from Launch Complex 41 at Cape Canaveral in a cloud of white exhaust
Liftoff, September 5, 1977, 12:56:01 UT: the Titan IIIE-Centaur carrying Voyager 1 leaves Launch Complex 41 at Cape Canaveral. NASA, public domain.

The trip, in five stops

1977SEP 5

Launch

Voyager 1 lifts off sixteen days after its twin, Voyager 2, on a faster path. Aboard is a gold-plated copper record carrying greetings in 55 languages, 115 images, the sounds of Earth and 90 minutes of music, in case anyone ever finds it.

1979MAR 5

Jupiter

Closest approach to Jupiter. Voyager 1 finds active volcanoes on the moon Io, the first ever seen beyond Earth, and sends back the Great Red Spot in a level of detail nobody had seen.

1980NOV 12

Saturn, and the exit

Closest approach to Saturn and a close pass of its moon Titan. The Titan flyby bends the trajectory up and out of the plane of the planets. There are no more stops after this.

1990FEB 14

The last pictures

From about 40 times the Earth-Sun distance, Voyager 1 turns around and photographs the planets, including Earth as a single pale pixel. The same day, the cameras are switched off for good to save power.

2012AUG 25

Interstellar space

Voyager 1 becomes the first human-made object to leave the heliosphere, the bubble of solar wind around the Sun, and start measuring the space between the stars.

Fourteen years later, it is still sending those measurements home, one day at a time.
Jupiter's Great Red Spot and surrounding swirling cloud bands as seen by Voyager 1
Jupiter's Great Red Spot, photographed by Voyager 1 during its 1979 approach. NASA, public domain.
The Pale Blue Dot photograph: a dark field crossed by bands of scattered sunlight, with Earth as a tiny bluish speck
The Pale Blue Dot, February 14, 1990. Earth is the speck about halfway down the brown band on the right, less than a pixel wide. NASA/JPL, public domain.

How you actually send it a message

This is the part that sounds made up and isn't. Here is the chain, link by link, from NASA's own engineering description of the Voyager radio system, published by JPL's DESCANSO program.

1. Only one antenna on Earth can do it. Voyager 1 is so far away that only one dish has enough power to reach it with commands: Deep Space Station 43, a 70-meter (230-foot) antenna at the Canberra Deep Space Communication Complex in Australia. JPL says it is "the only dish with enough signal power to send commands to the Voyagers." The dishes at Goldstone, California and Madrid can listen. They cannot talk.

2. It shouts at 18,000 watts. DSS-43 transmits the command signal at 18 kilowatts on S-band, about 2.1 gigahertz, not far from the frequencies your Wi-Fi uses. By the time that beam reaches Voyager, spread across a day's worth of space, almost none of it is left.

3. It talks slowly, on purpose. Commands go up at 16 bits per second. That is not a typo. A single 160-character text message would take more than a minute to send. The bits are Manchester-encoded: every bit is sent as a flip, high-to-low or low-to-high, so the receiver can find the rhythm even when the signal is buried in noise. That stream rides on a 512 Hz square-wave subcarrier.

4. The language is the machine's. There is no chat window. The flight team writes command sequences on the ground, checks them against software models of the spacecraft, and sends them up as raw instructions for Voyager's computers. One of them, the Flight Data Subsystem, runs in assembly language on 16-bit words. IEEE Spectrum reports each of the three onboard computers has 69.63 kilobytes of memory, less than most of the photos on this page.

5. Voyager answers with a light bulb. The reply goes back on X-band, about 8.4 gigahertz, from a dish 3.66 meters across, which was the largest solid reflector ever flown when it launched. The transmitter puts 12 or 18 watts into that dish. That is roughly a refrigerator bulb, aimed at a planet a light-day away. NASA lists the science data rate at 160 bits per second.

6. Error-correcting math does the rest. A signal that weak arrives full of errors. Voyager carried an experimental Reed-Solomon encoder for the outer planets, which cut the error rate in the received data from 5 in 1,000 bits to 1 in a million. The same family of codes later went into CDs, DVDs and QR codes.

Earth to Voyager 1Voyager 1 to Earth
AntennaDSS-43, 70 m, Canberra3.66 m high-gain dish
Power18,000 watts12 or 18 watts
FrequencyS-band, about 2.1 GHzX-band, about 8.4 GHz
Speed16 bits per second160 bits per second (science)
Travel time after Nov. 1824 hours24 hours
The 70-meter Deep Space Station 43 radio dish at Canberra pointed toward the sky, with hills behind it
Deep Space Station 43 at Canberra, Australia: the one antenna on Earth that can still send Voyager 1 a command. NASA/JPL-Caltech, public domain.
NASA diagram of the Voyager high-gain antenna showing the reflector, subreflector, support truss, S-band and X-band feeds, the low-gain antenna and the sun sensor
The other end of the conversation: NASA's diagram of Voyager's high-gain antenna, with its S-band and X-band feeds and the sun sensor that keeps it pointed home. NASA/JPL, public domain.

The weekly "are you still there"

Voyager assumes the worst about itself. Onboard is a Command Loss timer. If too long goes by without a valid command from Earth, the spacecraft concludes its own radio has failed and starts swapping to backup hardware, one piece at a time, trying to hear us again. It will run that routine four times. If it still hears nothing, it switches to a Backup Mission Load, a stored plan to keep doing science on its own.

So every week, the team sends a command whose only job is to reset that timer. It is the oldest keep-alive ping in the solar system.

Fixing a computer from a day away

In November 2023, Voyager 1 started sending back gibberish. Engineers ordered a full readout of the Flight Data Subsystem's memory and found the cause: one memory chip had failed. You cannot replace a chip 15 billion miles away, so the team rewrote the affected code, split it into pieces small enough to fit in the gaps left in memory, and moved it around the dead spot. There was so little room that they had to delete code for data modes nobody uses anymore.

The first fix went up through the Deep Space Network on April 18, 2024. The signal took about 22.5 hours to arrive. Readable data came back on April 20. "The size of the memory was the biggest challenge in this anomaly," project scientist Linda Spilker told IEEE Spectrum.

In March 2025 they did it again with hardware. Voyager 1's primary roll thrusters had been written off as dead since 2004. The team suspected a heater circuit switch had flipped the wrong way, sent the commands to flip it back, and waited a day to find out. The heaters warmed up. "It was such a glorious moment," propulsion lead Todd Barber told JPL.

Detailed NASA diagram of the Voyager spacecraft labeling the high-gain antenna, ultraviolet spectrometer, infrared spectrometer, photopolarimeter, cosmic ray and plasma instruments, Canopus star tracker, hydrazine thrusters, plasma wave antennas, magnetometers and radioisotope thermoelectric generators
The full instrument layout. Of Voyager 1's ten science instruments, only the magnetometer and the plasma wave instrument are still switched on; the rest have been turned off over the decades to save power. NASA, public domain.

Running on what's left

Voyager 1 runs on three radioisotope thermoelectric generators, which turn the heat of decaying plutonium into electricity. At launch they made about 158 watts each. That output drops every year, so NASA has been switching instruments off one by one: the cameras in 1990, the cosmic ray instrument in February 2025, the low-energy charged particle instrument in April 2026. As of now, two science instruments are still working.

Parts of it have already died. One of its two X-band transmitter amplifiers failed in 1987. Its ultra-stable oscillator failed in 1992. The team keeps routing around the losses, because the alternative is silence.

A Voyager spacecraft mounted on its support fixture inside a clean-room facility before launch
A Voyager spacecraft being prepared before launch in 1977. NASA, public domain.

The day before Vice City

On November 19, millions of people will start a game built by thousands of people, running on hardware that can draw a whole city in real time. The night before, a machine with 69.63 kilobytes per computer, a 12-watt voice and a record player bolted to its side will quietly be one light-day from home.

Both are worth a moment. Only one of them has been getting its patches from a full day away, for 49 years.

The gold-plated cover of the Voyager Golden Record, engraved with diagrams explaining how to play the record and where it came from
The cover of the Voyager Golden Record, engraved with instructions for whoever finds it: how to play it, at what speed, and how to find the Sun. NASA/JPL, public domain.

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