A Human-Made Object Is a Light-Day from Earth for the First Time

Dear Young Comrades,

Our Sun lives inside a vast bubble woven from the solar wind; this bubble shields our planets from the harsh radiation that comes from deep space. In August 2012 Voyager 1 crossed the outer boundary of this bubble, the surface called the heliopause, and became the first human-made object travelling among the stars. Every day it moves a little further into the unknown.

Summary

• What is happening? According to NASA, on 18 November 2026, around 09:16 Türkiye time, Voyager 1 will be a full light-day from Earth: about 25.9 billion kilometres. A radio signal travelling at the speed of light will take 24 hours to reach it. It will be the first human-made object to pass this threshold.
• How long did it take? 49 years, 2 months and 11 days since 5 September 1977. The craft is travelling at about 61,000 kilometres an hour towards the constellation Ophiuchus.
• Which boundaries has it crossed? In 2004 it crossed the "termination shock", where the solar wind slows. On 25 August 2012 it crossed the heliopause, the edge of the heliosphere. Its twin, Voyager 2, crossed the same boundary on 5 November 2018.
• What is the state of things today? The power has fallen to about half of what it was at launch, and it drops by about 4 watts every year. Each craft began with 10 science instruments; only 2 are working on Voyager 1, and 3 on Voyager 2. In April 2026 the low-energy charged-particle instrument (LECP) on Voyager 1, which had been on for about 49 years, was switched off.
• Recent weeks: In September 2026 engineers, in a risky manoeuvre called the "Big Bang", swapped three heaters and devices at the same moment for three devices that consume less power, and so pushed the next instrument shutdown past the summer of 2027. On 18–19 October no signal was received from the craft for two days. On 20 October the link returned; a thruster group had dropped out and the backups had come online.
• What lies ahead? In 2027, the 50th year of the journey. In the middle of the 2030s the signal will weaken beyond what the antennas of the Deep Space Network can hear. The craft will fall silent, but it will keep going: reaching the Oort cloud will take about 300 years, and crossing it about 30,000.
• What it means for us: Voyager is a machine made not for profit but for curiosity, with public funds, by the common intelligence of thousands of workers. The data it produces is open to everyone. In an age when space is marketed as the monopolies' "new market", Voyager reminds us of this: humanity's longest-lasting achievements are born in the patience of social labour spread across generations, and in the quarterly horizon of capital's balance sheet they have no place.

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The Detail

The Sun's bubble: what is the heliosphere?

The Sun constantly sprays charged particles at hundreds of kilometres a second. We call this the solar wind. This wind drags the Sun's magnetic field with it and inflates a vast bubble around us: the heliosphere. Outside the bubble is the interstellar medium: gas, dust and high-energy cosmic rays from the explosions of other stars and from supernova remnants.

The heliosphere works like a shield: it deflects a large share of the cosmic rays coming from the galaxy and weakens them before they reach the planets. This bubble has three important layers:

Boundary	What happens	Voyager 1	Voyager 2
Termination shock	The solar wind drops below the speed of sound, compresses and heats	December 2004 (~94 AU)	August 2007 (~84 AU)
Heliosheath	The turbulent region of the slowed wind	2004–2012	2007–2018
Heliopause	The boundary where the pressure of the solar wind equals that of the interstellar medium	25 August 2012 (~121 AU)	5 November 2018 (~119 AU)

(1 AU = the Earth–Sun distance, about 150 million km.)

Let us also correct a misconception: crossing the heliopause does not mean leaving the Solar System. The Sun's gravity reaches much further, out to the Oort cloud of trillions of icy bodies. Voyager 1 has entered "interstellar space", but it is still wandering in the garden of the Sun's gravitational house. Reaching the end of the garden will take tens of thousands of years.

How we understood Voyager's crossing of the heliopause is a story of its own. The plasma instrument on the craft had failed years earlier. Scientists calculated the density of the medium by "listening", with the plasma wave instrument, to the surrounding plasma set trembling by a pressure wave from an eruption on the Sun. The density came out about 40 times higher than inside the heliosphere: the craft was now swimming in another "sea". Closing the gap of a broken instrument, creatively, with another instrument: that, too, is a little of Voyager's whole story.

A short history of the journey

In the early 1970s astronomers noticed that the outer planets (Jupiter, Saturn, Uranus, Neptune) would fall into an alignment that comes about once every 175 years. A craft launched at the right time could take speed from one planet's gravity, like a sling, and pass on to the next. Two craft used this chance.

Date	Event
20 August 1977	Voyager 2 was launched
5 September 1977	Voyager 1 was launched (on a faster trajectory, it overtook its sibling)
1979	Both at Jupiter; the first active volcanoes beyond Earth, on Io
1980–1981	Saturn and its rings; Voyager 1 turned aside for Titan and left the plane of the planets
1986	Voyager 2 at Uranus (the only craft to visit this planet)
1989	Voyager 2 at Neptune (the only craft to visit this planet)
14 February 1990	Voyager 1 turned and looked back: the "Pale Blue Dot" photograph. The cameras were then switched off for good
February 1998	Voyager 1 passed Pioneer 10 and became the most distant human-made object
2012 / 2018	Voyager 1 and 2 crossed the heliopause
November 2023 – April 2024	Meaningless data because of a failed memory chip in Voyager 1's flight computer; engineers solved it from a distance by moving the code to other parts of the memory
February 2025	The cosmic-ray instrument (CRS) on Voyager 1 was switched off
March 2025	The LECP on Voyager 2 was switched off
17 April 2026	The LECP on Voyager 1 was switched off
September 2026	The "Big Bang" power manoeuvre on Voyager 1
18 November 2026	Voyager 1 a light-day away

The mission was first expected to last five years. Today we have gone past that span for the ninth time.

Where are we today? (October 2026)

Distance and time. At the beginning of October a signal leaving Voyager 1 was reaching Earth in 23 hours, 52 minutes and 30 seconds. According to the NASA calculation reported by EarthSky, this span will pass 24 hours on 18 November. The mission manager, Suzanne Dodd, sums up the situation like this: you send the message, you go home, you wait two days. A command going out and its reply coming back now takes two full days. As NASA also stresses, this threshold is symbolic: on that day nothing on the craft or around it will change. What changes is the measure of how far we have been able to reach.

Power. The Voyagers run not on solar panels but on radioisotope thermoelectric generators (RTGs), which turn the decay heat of plutonium-238 into electricity. This far from the Sun a panel is useless. As the plutonium diminishes and the thermoelectric couples age, each craft loses about 4 watts a year. Today's power is about half of what it was at launch. In JPL's phrase, their share of energy is "razor thin".

The most dangerous moment of this year was 27 February: during a planned roll manoeuvre, Voyager 1's power dropped unexpectedly. Following the order it had set years earlier with the science team, the team switched off the LECP on 17 April. This instrument had been working almost without a break since 1977; it measured the pressure fronts and the particle density in the interstellar medium. Even so it does not count as wholly dead: a small half-watt motor in the instrument is still spinning, so that it can be switched on again later.

Instruments still working.

	Voyager 1	Voyager 2
Science instruments at the start	10	10
On today	2: magnetometer (MAG), plasma wave instrument (PWS)	3: MAG, PWS, cosmic-ray instrument (CRS)
Distance from Earth	~25.8 billion km (25.9 on 18 November)	~3.2 billion km closer
Arrival at one light-day	18 November 2026	Around November 2035
Direction	The constellation Ophiuchus, "above" the plane of the planets	Towards Andromeda, "below" the plane

The "Big Bang" manoeuvre. The solution the engineers found uses a subtlety of 1970s hardware. Three devices that keep the craft warm and consume power are switched off, and three other devices, whose heat spreads to the right point but which use less power, are switched on at the same moment. It has to be at the same moment, because if the sequence breaks the fuel lines can freeze. It was tried first on Voyager 2, which is relatively closer and has more power to spare; as The Register reported, it bought Voyager 2's instruments at least another year. At the beginning of September the same operation was carried out on Voyager 1. According to NASA, without this another instrument on Voyager 1 would have had to be switched off in the summer of 2027.

The silence in October. On 18 and 19 October the Deep Space Network, in two planned attempts 24 hours apart, could not find Voyager 1's signal. On 20 October the signal returned. The first look shows that a thruster group had dropped out and the fault-protection software had brought the backup thrusters online and put the craft into safe mode. The words of the mission manager, Kareem Badaruddin, describe the present stage of the journey well: they are seeing the craft do something like this for the first time, but they are now at a point where they have to "expect the unexpected" (NASA, Phys.org). The root cause is still being investigated.

The years ahead

• 2027: The 50th year of the launch. Thanks to the power manoeuvre, the remaining instruments are expected to see this threshold.
• The early 2030s: As the power falls, the last instruments will also switch off in turn. For a while the craft can live as a "carrier signal", sending only engineering data.
• Around 2036: The signal will weaken beyond what the antennas on Earth can detect.
• About 300 years from now: Voyager 1 will reach the inner edge of the Oort cloud; crossing the cloud will take about 30,000 years.
• About 40,000 years from now: Voyager 1 will come within 1.6 light-years of the star Gliese 445. Probably no one will say "hello" to it; but the craft will go there carrying a note from us.

The Golden Record and the Pale Blue Dot

On the body of each craft there is a gold-plated copper record: greetings in 55 languages, music from every part of the world, the sounds of nature, a mother's voice, a baby's cry, a heartbeat, 115 images. Carl Sagan led the team that prepared the record. The record is a letter written without knowing who will find it.

In 1990, at Sagan's insistence, Voyager 1 turned and photographed the Earth. From six billion kilometres the Earth was a point smaller than a pixel, inside a sunbeam. On this photograph Sagan wrote a famous text recalling the blood that all the wars, all the empires and all the "conquerors" had spilled to rule a small corner of this point. That photograph taught a human generation that borders, flags and property are not visible from space.

The class window: who made Voyager, and for whom?

Science news often tells achievements of this kind as "a handful of genius scientists" or "the greatness of a country". Voyager's real story is the story of social labour.

Crystallised labour. Voyager is the embodied labour of thousands of people, from mine workers to metallurgists, from the plant workers who processed the plutonium to the solderers, from the programmers to the technicians who maintain the giant antennas in Australia, Spain and California. If we can speak to the craft today, we owe it to young engineers trying to learn the Fortran and machine-language code written in the seventies from the documents retired engineers left behind, and from the engineers themselves. The memory-chip failure of 2024 was solved from 25 billion kilometres away, by loading a new memory map onto a thirty-year-old computer. This is a living example of knowledge being passed between generations, that is, of the knowledge commons.

Profit, or curiosity. Voyager had no market return, and it could not have had one. No capitalist in 1977 invests by saying "let us send a craft to Neptune, and in 2026 let us measure the density of the interstellar plasma", because this has no rate of profit, no exit strategy, no share price. This journey was possible only because a part of the social surplus was set aside publicly and with a long-term horizon. By the figure NASA has given, Voyager's total cost up to the Neptune encounter in 1989 was around 865 million dollars; today that is a small fraction of what a technology monopoly pours into artificial-intelligence data centres in a single quarter.

Let us not forget the historical setting either: Voyager was born inside the Cold War, in the middle of the two systems' race for scientific supremacy. The other side of that race, as we told in our piece on Sputnik and the space race, was the road the Soviets opened. Competition sped science up; but the curiosity and the labour inside Voyager outlived the propaganda account of that race.

Open data. Voyager's data is open to everyone. A secondary-school student and a doctoral student in Ankara can reach the same raw data. In a period when the artificial-intelligence monopolies are enclosing humanity's common knowledge and locking it into closed models, this principle is not a small detail. This is also what we defended in our piece on public artificial intelligence: knowledge produced with public resources should stay public.

Voyager's space	The monopolies' space
It begins with a public budget and a scientific question	It begins with a funding round and a market-share target
Horizon: decades, generations	Horizon: the quarterly balance sheet, the flotation calendar
Data open to everyone	Data a trade secret, access charged for
Measure of success: knowledge learned	Measure of success: valuation, the share price
The accumulation of labour stays in the institution and is passed on	Labour is contractual, and knowledge scatters with the redundancies
A greeting in 55 languages on the record	Tens of thousands of advertising-carrier satellites in orbit
The sky, humanity's common heritage	The sky, a new field of property

The budget axe. This public model does not live by itself. In 2025, when the US administration proposed cutting NASA's science budget by nearly half, hundreds of NASA workers wrote openly, in the "Voyager Declaration" named after this journey (NNPA), that the cuts threatened the missions. Under pressure from scientists, engineers and the public, Congress rejected the deep cuts and passed a budget of 24.4 billion dollars. The lesson is plain: public science lives for as long as the people who claim it are organised.

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Concrete Tasks

1. Turn 18 November into a gathering. At your school, in your association, in your neighbourhood, hold a small "one light-day" evening: show the Pale Blue Dot photograph, play the sounds on the Golden Record, talk about the labour that made Voyager.
2. Touch the open data. Follow the data and the live distance counter on NASA's Voyager pages; experience science as the work of a participant.
3. Defend public science. In Türkiye too, science budgets, TÜBİTAK projects and the research posts of the universities are constantly being trimmed. Support the organising of science workers.
4. Pass the knowledge on. What has kept Voyager alive is the ability to pass older engineers' knowledge to the young. In your own organisations and your own workplaces, make the passing on of knowledge a collective duty.
5. Count the sky as a commons. Against orbits, frequencies and space data becoming the property of a few monopolies, defend the principle that space is humanity's common heritage.

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Dear Young Comrades,

What excites us in Voyager's story is the distance, and something more. What is truly moving is the existence of people who began a work even knowing they would not see its end. Most of those who made that craft in 1977 are retired today, or no longer living. Most of those who keep the craft alive today had not been born when it was launched. Between them there is a single bond: a common aim, knowledge passed from generation to generation, and the labour of people who trust one another.

Our struggle is like this too. None of us may see, in a single lifetime, the whole of the world we want to build. But each generation, like those engineers who found a way to keep alive a craft whose power was falling, can carry the journey one step further with the means in hand. From Voyager we can learn to measure with another instrument where one has failed, to set priorities wisely where resources have dwindled, to expect the unexpected, and never to break the link.

On the morning of 18 November, at sixteen minutes past nine, look at the sky. You will not see it, of course; but a light-day away, a small machine made from humanity's common labour will be going on its way, carrying "hello" in 55 languages. And this journey will remain one of the finest proofs of what humanity can do, not for profit, but in order to know and to share.

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