The Hardest Software Update In History（原声文稿）

It's November 14, 2023.

15 billion miles from Earth, the farthest spacecraft humanity has ever built, stops working.

Voyager 1 has been flying through space for 46 years.

Every day it sends data back to NASA, but today the message makes no sense.

Inside its 1970s computer, something has broken. Nobody knows what.

Every question the engineers ask takes 45 hours to answer, and most of the people who build that computer are long retired or dead.

Back on Earth, only a dozen engineers are left to look after the probe.

They work from a rented office in California, right next to McDonald's.

To save Voyager 1 from being lost forever, they have to pull off their hardest software update in history. memory.

To understand why this is so hard to fix, we have to go back to 1977.

That summer, NASA launches two identical spacecrafts, Voyager 2 in August and Voyager 1 about two weeks later.

The plan is simple, fly past Jupiter and Saturn, take pictures and send them home. They are designed to last 5 years.

So they are built before the early 1970s has to offer. Each of Voyager's computer has about 70 kilobytes of memory.

A single photo on your phone is roughly 50 times larger.

Data it can't send right away goes on to a tape recorder, an 8 -track, and the radio that has to reach Earth from billions of miles away runs on about 23 watts, roughly the power of the light bulb in your fridge.

But the engineers make two decisions that will matter decades later.

First, Voyager software can be changed in flight. It's one of the first spacecrafts built that way.

If something goes wrong, you couldn't send it to you instructions.

Second, they armoured the electronics against the radiation, because Jupiter is brutal.

Nobody knows yet that the shielding would matter even more 50 years later.

On the outside, they attached a golden record.

Music, greetings in 55 languages and pictures of Earth. The mission works better than anyone hoped.

In fact, Voyager 1 finds active volcanoes on Jupiter's moon Io.

It flies past Saturn in its rings, and on Valentine's Day in 1990, almost 4 billion miles out, it turns its camera back towards home one last time.

Earth is a speck smaller than a single pixel.

Then it just keeps going.

In August 2012, 35 years after launch, Voyager 1 leaves the bubble of the Sun influence and enters interstellar space. the first human -made object ever to do it.

Back on Earth, the team that once filled buildings shrinks to about a dozen people.

They move into a rented office in Altadena.

Year after year they keep two aging spacecraft alive while the plutonium that powers them gives a little less every year.

Until November 14, 2023.

When Voyager's data turned into an endless pattern, project manager Suzanne Dot and her team know they're in serious trouble.

Voyager 1 has three main computers and each has one job.

The first to receive commands from Earth, the second keeps the spacecraft steady and its dish pointed at home.

If the dish drifts by even a fraction of a degree, the radio beam misses Earth and Voyager is lost for good.

The third is the Flight Data Subsystem or FDS.

It collects the measurements from the science instruments, ad health reports from the spacecrafts and packages everything into a stream of ones and zeros that get sent home.

The team can tell that Voyager is still receiving the commands and is still pointing at Earth, so the first two computers seem fine. The problem is the FDS.

It's like calling someone who hears every word you say but can only answer with a dial tone. And every attempt to fix it is extremely slow.

Commands go out through NASA's Deep Space Network, radio dishes 230 feet across, in California, Spain and Australia.

At the speed of light, a signal needs 22 .5 hours to reach Voyager 1. The answer needs another 22 .5 to come back.

Every question costs almost 2 days.

Then there's the computer itself.

The FDS was custom -built by General Electric in the early 1970s.

It's programmed in assembly language and works in 16 -bit words. There's no modern manual.

When something breaks, the team has to dig through decades -old memos, written by engineers who never imagined Voyager would still be flying today.

Project scientist Linda Spilker later compared to an archaeological dig. A few people are still around to remember working on their hardware. Most are not.

They are trying to repair brain they can't see, using 50 -year -old notes 45 hours at a time.

In December, the team tries the obvious move. They restart the FDS.

45 hours later, the answer arrives. The same pattern.

They switch instruments on and off, one by one, to see if anything changes. 45 hours, the same pattern.

Meanwhile, everything Voyager measures out there is lost.

First, readings from a place only two spacecraft have ever reached gone for good.

Weeks turn into months and Voyager 1 is 46 years old. Every failed attempt looks a little more like the end.

So they try something different.

On March 1st, 2024, the sender command the team calls a poke.

It nudges the FDS to run different sequences in its software in case it can be coaxed around in whatever is broken.

45 hours later, on March 3rd, something changes.

One section of the data stream looks different from the rest.

It's still not in Voyager's normal format.

Nobody on the team knows what it is. The breakthrough comes from outside the Voyager team.

An engineer at a deep space network, the people who run the giant antennas, takes the strange signal and manages to decode it.

By March 10, the team knows what they're looking at.

A complete readout of the FDS memory.

For the first time in almost four months they can see inside Voyager's brain.

They compare it line by line with a readout saved before the failure, and they find it. One memory chip has failed.

About 3 % of the computer's memory is now unusable.

Inside that chip the engineers find a single bit that's stuck, frozen at the same value no matter what.

and one bit out of more than half a million.

And that chip had part of the software the FDS needs to package Voyager's data. While the chip is broken, the code is gone. What broke it? No one knows.

Maybe that chip simply wore out after 46 years in the cold.

Or maybe a cosmic ray, a particle, flung across the galaxy at nearly the speed of light, punched through Voyager and hit their sex spot.

Out here, beyond the sun -protective bubble, Voyager is among them.

Either way, you can't replace a chip with 15 billion miles away.

Without that code, Voyager 1 will never speak again. Unless they can move it.

The idea sounds simple.

Take the code that lived on the broken chip and put it somewhere else in the FDS memory. The problem is space.

Remember, about 70 kilobytes and almost every byte already in use, Linda Spiker called the size of the memory the biggest challenge of the whole anomaly.

There is no single empty spot big enough for the missing code.

So, the team does something you would never do with modern software.

They cut the code into fragments and tuck each one into a different gap scattered across memory, like a game of Tetris, where every piece has to land perfectly the first time.

But even in pieces, the code doesn't fit.

They need more room, so they go looking for software Voyager doesn't need anymore. And they find it.

Back at Jupiter, Voyager could send data back home at more than 100 ,000 bits per second.

That took special high -speed modes and code run them.

Out here, Voyager will never be that fast again. So they decide to override it.

To save Voyager's future, they delete a piece of its past. Even that is dangerous.

Some of the old code is shared with Modes Voyager still uses.

They delete the wrong piece and they break the very thing they're trying to save. Then comes the hardest part.

In the 1970s computer, instructions point to exact memory addresses.

Move a piece of code and everything that pointed to it now points to the wrong place.

Every one of these references has to be found and rewritten, so the pieces can still jump to each other and run as one program.

One wrong address could override code the FTS still depends on and turn a broken computer into a dead one. And every test costs two days.

– only the code that packages Voyager's engineering data, its health reports. If that works, the science can come next.

On Thursday, April 18, 2024, a deep -space network dish turns toward a constellation of visuals and sends the patch into the dark.

It crosses the distance to the moon in just over a second, to mars in minutes, to Jupiter in another hour, to Neptune in about four. more.

And then for another 18 hours, nothing but empty space.

Until it reaches a 46 -year -old computer in interstellar space.

The computer writes the new fragments into its memory, Vojta answers, and that answer begins its own 22 .5 -hour trip home.

Set of April 20, several dozen scientists and engineers guard in a conference room at NASA's Jet Propulsion Laboratory. others joined from home.

On their screens, pages waiting to be filled with data, each for each subsystem.

Linda Speicher later said that the room was so quiet you could have heard a pin drop.

And the pages begin to fill.

Line by line, temperatures, voltages, the status of every sifting on board.

For the first time in 5 months, Voyager 1 is telling them exactly how it's doing. The patch worked on the first try.

In May, the team repeats the surgery for the code that handles science. But late May, two instruments are back.

By mid -June 2024, all four of Voyager 1's remaining science instruments are sending data from interstellar space again.

On June 9th, 2024, days before NASA announces that Voyager 1 is fully back, Ed Stone dies at 88.

He had been Voyager's project bear scientist for 50 years, from 1972 until 2022. The spacecraft he guided outlived him.

It will outlive everyone who built it. But time is running out.

Voyager's plutonium generators lose about 4 watts of power every year. To keep it alive, the team switches off whatever it can.

In February 2025, the cosmic ray instruments goes dark.

Then, on February 27, 2026, during a routine roll maneuver, Voyager 1's power drops more than expected.

Any lower and the spacecraft's own fault protection could have kicked in.

In April, the team switches off another instrument to stay ahead of it. The order of the shutdowns was agreed on years ago. Nobody has to choose in a panic.

Today, Voyager 1 has two science instruments left.

one that listens to plasma waves and one that measures magnetic fields and NASA is preparing another risky maneuver nicknamed the Big Bang to squeeze out a little more power and still it keeps going at 38 ,000 miles per hour a little farther with every second.

On November 18, 2026, Voyager 1 will be 16 .1 billion miles from Earth so far that light itself needs a full day to get there.

Nothing humans has ever built has been this far from home.

Susan Dott has put it simply.

Say good morning to Voyager on a Monday at 8am and the reply arrives on Wednesday morning.

Sometimes in the 2030s the power will run out for good. The last instrument will go quiet.

The transmitter will fall silent and Voyager 1 will keep drifting through the Milky Way for billions of years, carrying its golden record, a message from a planet in cano longer sea.

For 46 years, Voyager 1 had been talking to us. Then, a single bit nearly took its voice.

It didn't, because a small team in a rented office next to McDonald's found a way to revive a computer 15 billion miles away.

One fragment at a time. 45 hours at a time. Watcher 1 is still talking. For now.