Why NASA’s twin Voyagers probes are the most important spacecraft ever launched — and could be the last evidence of humanity’s existence

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An illustration of a Voyager probe next to a golden record and cover. NASA/JPL-Caltech

About 1 billion years from now, the sun will begin to die, blow off its outer atmosphere, and engulf our tiny planet in hot plasma.

Luckily, the galaxy will have NASA’s twin Voyager spacecraft to remember us by.

The two nuclear-powered probes launched 40 years ago and became the first and only robots to take close-up photographs of Uranus and Neptune, the planets’ moons and rings, and other objects in the outer solar system.

The Voyagers also carried with them a golden record of sounds, images, and other information life on Earth — a basic human catalogue that aliens might one day discover and decode.

The mission is now detailed in a remarkable detail for PBS documentary called “The Farthest“, which premiered on August 23 and will re-air on September 5 (the date of Voyager 1’s launch).

“Fifty years from now, Voyager will be the science project of the 20th century,” Brad Smith, a Voyager imaging scientist, said in the movie.

Here’s why many scientists and engineers not only hail the Voyagers as the farthest, fastest, and longest-lived space mission, but also one of humanity’s greatest endeavours.

[slideshow]
[slide
permalink=”/#nasa-began-working-on-the-voyager-mission-in-1972-with-a-budget-of-865-million-or-roughly-5-billion-in-2017-adjusted-dollars-1″
title=”NASA began working on the Voyager mission in 1972 with a budget of $865 million, or roughly $5 billion in 2017-adjusted dollars.”
content=”Source: NASA/JPL-Caltech, Bureau of Labour Statistics
image=”http://static.businessinsider.com/image/59a0922e79bbfd22008b500b”
source=”NASA”
caption=”An illustration of NASA’s Voyager spacecraft drifting through space.”
credit_href=”http://voyager.jpl.nasa.gov/spacecraft/”
]
[slide
permalink=”/#the-goal-was-to-tour-the-outer-solar-system-using-a-planetary-alignment-that-happens-just-once-every-176-years-the-gravity-of-the-planets-would-speed-up-the-spacecraft-allowing-at-least-one-probe-to-visit-uranus-and-neptune-for-the-first-time-2″
title=”The goal was to tour the outer solar system using a planetary alignment that happens just once every 176 years. The gravity of the planets would speed up the spacecraft, allowing at least one probe to visit Uranus and Neptune for the first time.”
content=”Source: ‘The Farthest’/PBS


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[slide
permalink=”/#nasa-worried-that-jupiters-radiation-fields-might-short-circuit-the-voyagers-so-engineers-shielded-and-grounded-cables-of-the-probes-with-kitchen-grade-aluminum-foil-it-worked-3″
title=”NASA worried that Jupiter’s radiation fields might short-circuit the Voyagers. So engineers shielded and grounded cables of the probes with kitchen-grade aluminium foil. (It worked.)”
content=” 

Source: ‘The Farthest’/PBS
image=”http://static.businessinsider.com/image/59a0902e79bbfdba408b4c37″
source=”NASA/JPL-Caltech”
caption=”Kitchen-grade aluminium foil was used to insulate and ground the outer cabling of the Voyager spacecraft.”
credit_href=”https://images.nasa.gov/#/details-PIA21736.html”
]
[slide
permalink=”/#voyager-2-launched-into-space-on-august-20-1977-to-the-confusion-of-many-people-voyager-1-launched-several-weeks-later-on-september-5-1977-4″
title=”Voyager 2 launched into space on August 20, 1977. To the confusion of many people, Voyager 1 launched several weeks later, on September 5, 1977.”
content=””
image=”http://static.businessinsider.com/image/59a0949479bbfd0d288b4f8a”
source=”NASA/JPL”
caption=”The Voyager 2 spacecraft launching from NASA’s Kennedy Space Center at Cape Canaveral, Florida, on August 20, 1977.”
credit_href=”https://images.nasa.gov/#/details-PIA01480.html”
]
[slide
permalink=”/#but-as-scientists-featured-in-the-farthest-explain-they-were-thinking-long-term-voyager-1-would-move-faster-and-eventually-overtake-voyager-2-5″
title=”But as scientists featured in ‘The Farthest’ explain, they were thinking long-term: Voyager 1 would move faster and eventually overtake Voyager 2.”
content=”Source: ‘The Farthest’/PBS


image=””
source=””
caption=””
credit_href=””
]
[slide
permalink=”/#both-launches-left-scientists-nerves-frayed-for-example-unforeseen-rocket-vibrations-made-voyager-2s-computer-go-on-the-fritz-and-didnt-let-people-control-it-for-days-fortunately-a-remote-software-patch-fixed-the-problem-6″
title=”Both launches left scientists’ nerves frayed. For example, unforeseen rocket vibrations made Voyager 2’s computer go on the fritz and didn’t let people control it for days. Fortunately, a remote software patch fixed the problem.”
content=”‘That was a cliffhanger,’ Fred Locatell, an engineer on the Voyager mission, said in the film. ‘That was the end of the mission. That could have been the end of the mission.’

Source: ‘The Farthest’/PBS
image=”http://static.businessinsider.com/image/59a0d5816eac40d11c8b4efd”
source=”Smithsonian National Air and Space Museum”
caption=”Part of the Voyager spacecraft’s computing system.”
credit_href=”https://airandspace.si.edu/collection-objects/power-supply-board-voyager-spacecraft”
]
[slide
permalink=”/#meanwhile-voyager-1s-liquid-fueled-rocket-sprung-a-leak-during-launch-the-rocket-corrected-for-this-by-burning-extra-fuel-leaving-just-35-seconds-worth-of-thrust-7″
title=”Meanwhile, Voyager 1’s liquid-fuelled rocket sprung a leak during launch. The rocket corrected for this by burning extra fuel — leaving just 3.5 seconds’ worth of thrust.”
content=”Had the rocket leaked any more fuel than it did, Voyager 1 could have failed.

‘Instead of getting to Jupiter, you know, we would have gotten almost to Jupiter — then it would have come back toward the sun. Which would not have been good,’ John Casani, the mission’s project manager, said in the film.

Source: ‘The Farthest’/PBS 


image=””
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[slide
permalink=”/#both-voyagers-explored-jupiter-catching-a-speed-boost-along-the-way-before-the-probes-no-one-had-ever-seen-such-detailed-images-of-jupiter-8″
title=”Both Voyagers explored Jupiter, catching a speed boost along the way. Before the probes, no one had ever seen such detailed images of Jupiter…”
content=””
image=”http://static.businessinsider.com/image/5963b181f50184a5028b5373″
source=”NASA/JPL; Björn Jónsson/IAAA”
caption=”The Great Red Spot, as seen by the Voyager 1 probe in 1979.”
credit_href=”https://apod.nasa.gov/apod/ap110502.html”
]
[slide
permalink=”/#or-those-of-the-gas-giants-many-moons-including-europa-this-ice-world-hides-a-subsurface-ocean-thats-estimated-to-contain-more-water-than-exists-on-all-of-earth-9″
title=”…Or those of the gas giant’s many moons, including Europa. This ice world hides a subsurface ocean that’s estimated to contain more water than exists on all of Earth.”
content=”Source: Business Insider
image=”http://static.businessinsider.com/image/59a09eaf6eac402a008b5395″
source=”NASA/JPL”
caption=”A photo mosaic of Jupiter’s icy moon Europa, as photographed by NASA’s Voyager 2 probe.”
credit_href=”https://photojournal.jpl.nasa.gov/catalog/PIA00366″
]
[slide
permalink=”/#both-probes-also-took-extraordinarily-detailed-photos-of-saturn-10″
title=”Both probes also took extraordinarily detailed photos of Saturn…”
content=””
image=”http://static.businessinsider.com/image/59a09fa56eac401c008b5362″
source=”NASA/JPL-Caltech”
caption=”A false-colour image of Saturn taken by Voyager 1 in 1980.”
credit_href=”https://www.nasa.gov/feature/35th-anniversary-of-the-voyager-1-saturn-flyby”
]
[slide
permalink=”/#and-its-moons-such-as-titan-many-scientists-think-of-this-world-as-a-proto-earth-due-to-its-similar-size-hazy-atmosphere-and-abundance-of-carbon-11″
title=”…And its moons, such as Titan. Many scientists think of this world as a ‘proto-Earth’ due to its similar size, hazy atmosphere, and abundance of carbon.”
content=””
image=”http://static.businessinsider.com/image/59a0a02c6eac402b008b534b”
source=”NASA/JPL”
caption=”Saturn’s hazy moon Titan, as seen by NASA’s Voyager 1 spacecraft.”
credit_href=”https://images.nasa.gov/#/details-PIA01532.html”
]
[slide
permalink=”/#voyager-2-was-the-first-and-so-far-only-robot-to-fly-by-and-photograph-uranus-it-discovered-the-planet-is-inexplicably-tipped-on-its-side-12″
title=”Voyager 2 was the first and so far only robot to fly by and photograph Uranus. It discovered the planet is inexplicably tipped on its side…”
content=””
image=”http://static.businessinsider.com/image/58c6c876c1407723028b4c20″
source=”NASA/JPL-Caltech”
caption=”A true-colour photo of Uranus (left) and a false colour image (right) taken at the turn of 1986 by NASA’s Voyager 2 probe.”
credit_href=”https://www.nasa.gov/mission_pages/voyager/pia00032.html”
]
[slide
permalink=”/#has-dozens-of-moons-13″
title=”…Has dozens of moons…”
content=””
image=”http://static.businessinsider.com/image/59a0e1716eac402a008b542a”
source=”NASA/JPL-Caltech”
caption=”A photo of Uranus’ moon Miranda taken by the Voyager 2 spacecraft.”
credit_href=”https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18185″
]
[slide
permalink=”/#has-rings-of-ice-and-dust-14″
title=”…Has rings of ice and dust…”
content=””
image=”http://static.businessinsider.com/image/59a0dea86eac401b008b53a4″
source=”NASA/JPL-Caltech”
caption=”A photo of Uranus taken by Voyager 2 in 1986 that’s edited to show its moon and rings.”
credit_href=”https://apod.nasa.gov/apod/ap990531.html”
]
[slide
permalink=”/#voyager-2-is-still-the-only-probe-ever-to-fly-by-the-outermost-planet-neptune-15″
title=”Voyager 2 is still the only probe ever to fly by the outermost planet, Neptune…”
content=””
image=”http://static.businessinsider.com/image/56afcb18c08a80880e8be2f8″
source=”NASA”
caption=”A false-colour view of Neptune from Voyager 2 that reveals a haze of methane gas in red.”
credit_href=”https://en.wikipedia.org/wiki/Neptune#/media/File:Neptune_Full.jpg”
]
[slide
permalink=”/#see-the-gas-giants-enormous-dark-spot-storm-16″
title=”…See the gas giant’s enormous Dark Spot storm…”
content=”Source: ‘The Farthest’/PBS


image=””
source=””
caption=””
credit_href=””
]
[slide
permalink=”/#and-photograph-its-large-and-icy-moon-triton-which-was-caught-spewing-geysers-of-nitrogen-from-its-surface-17″
title=”…And photograph its large and icy moon Triton, which was caught spewing geysers of nitrogen from its surface.”
content=””
image=”http://static.businessinsider.com/image/59a09cfd79bbfd1d008b5076″
source=”NASA/JPL/USGS”
caption=”A mosaic of images of Neptune’s moon Triton, as photographed by NASA’s Voyager 1 probe in 1989.”
credit_href=”https://images.nasa.gov/#/details-PIA00317.html”
]
[slide
permalink=”/#although-both-probes-finished-their-main-missions-decades-ago-theyve-moved-beyond-the-arguable-edge-of-the-solar-system-and-into-a-region-between-stars-18″
title=”Although both probes finished their main missions decades ago, they have moved beyond the arguable edge of the solar system — and into a region between stars.”
content=””
image=”http://static.businessinsider.com/image/59a0e81079bbfd22008b5176″
source=”NASA/ESA/G. Bacon (STScI)”
caption=”An illustration of a Voyager probe leaving the solar system.”
credit_href=”https://www.nasa.gov/feature/goddard/2017/hubble-provides-interstellar-road-map-for-voyagers-galactic-trek”
]
[slide
permalink=”/#the-spacecraft-still-regularly-contact-earth-from-more-than-106-trillion-miles-away-reporting-what-data-they-can-with-the-instruments-that-still-work-and-are-turned-on-19″
title=”The spacecraft still regularly contact Earth from more than 10.6 trillion miles away, reporting what data they can with the instruments that still work and are turned on.”
content=””
image=”http://static.businessinsider.com/image/59a0e92979bbfd1d008b510f”
source=”NASA”
caption=”The Canberra antennas of the Deep Space Network regularly listen for signals from the Voyager probes.”
credit_href=”https://www.nasa.gov/directorates/heo/scan/services/networks/txt_dsn.html”
]
[slide
permalink=”/#they-voyagers-still-work-more-than-40-years-after-launch-because-theyre-powered-by-plutonium-238-a-radioactive-byproduct-of-cold-war-nuclear-weapons-production-20″
title=”They Voyagers still work more than 40 years after launch because they’re powered by plutonium-238 — a radioactive byproduct of Cold War nuclear weapons production.”
content=””
image=”http://static.businessinsider.com/image/58a372165490571d008b45d0″
source=”Department of Energy, via Wikipedia”
caption=”A puck of plutonium-238 dioxide glowing under its own warmth.”
credit_href=”https://commons.wikimedia.org/wiki/File:Plutonium_pellet.jpg”
]
[slide
permalink=”/#special-materials-surround-the-plutonium-to-convert-its-escaping-heat-into-electricity-each-voyager-has-three-nuclear-power-supplies-and-together-they-generated-420-watts-at-launch-about-half-the-power-of-a-microwave-oven-21″
title=”Special materials surround the plutonium to convert its escaping heat into electricity. Each Voyager has three nuclear power supplies, and together they generated 420 watts at launch — about half the power of a microwave oven.”
content=”Because half of any amount of plutonium-238 decays in 87.7 years, these radioisotope power sources now generate about three-quarters of that wattage.


image=””
source=””
caption=””
credit_href=””
]
[slide
permalink=”/#even-after-these-nuclear-batteries-die-however-the-probes-will-continue-carrying-golden-records-loaded-up-with-the-sights-and-sounds-of-earth-22″
title=”Even after these nuclear batteries die, however, the probes will continue carrying golden records loaded up with the sights and sounds of Earth.”
content=””
image=”http://static.businessinsider.com/image/59a0e59f79bbfd0d288b50a5″
source=”NASA/JPL-Caltech”
caption=”The golden record and American flag attached to each of NASA’s Voyager probes.”
credit_href=”https://images.nasa.gov/#/details-PIA17035.html”
]
[slide
permalink=”/#the-cover-to-each-record-includes-careful-instructions-on-how-to-use-a-stylus-to-read-the-data-these-directions-arent-in-english-though-but-rather-in-mathematical-terms-an-intelligent-alien-might-understand-23″
title=”The cover to each record includes careful instructions on how to use a stylus to read the data. These directions aren’t in English, though, but rather in mathematical terms an intelligent alien might understand.”
content=””
image=”http://static.businessinsider.com/image/59a0541679bbfdba408b4848″
source=”Nasa”
caption=””
credit_href=”http://voyager.jpl.nasa.gov/spacecraft/goldenrec1.html”
]
[slide
permalink=”/#this-in-the-long-run-may-be-the-only-evidence-that-we-ever-existed-frank-drake-who-worked-on-the-golden-record-project-and-also-came-up-with-the-drake-equation-said-in-the-film-24″
title=”‘This, in the long run, may be the only evidence that we ever existed,’ Frank Drake, who worked on the golden record project (and also came up with the Drake Equation), said in the film.”
content=””
image=”http://static.businessinsider.com/image/57e3e108077dcc1b008b7792″
source=”NASA/Flickr”
caption=”A view of Africa taken by Apollo 11 astronauts on July 20, 1969.”
credit_href=”https://www.flickr.com/photos/nasacommons/5052744618″
]
[slide
permalink=”/#president-jimmy-carter-left-what-is-perhaps-the-most-prescient-message-to-anyone-or-anything-who-discovers-the-probesthis-is-a-present-from-a-small-distant-world-a-token-of-our-sounds-our-science-our-images-our-music-our-thoughts-and-our-feelings-we-are-attempting-to-survive-our-time-so-we-may-live-into-yours-25″
title=”President Jimmy Carter left what is perhaps the most prescient message to anyone (or anything) who discovers the probes: ‘This is a present from a small distant world, a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live into yours.'”
content=””
image=”http://static.businessinsider.com/image/59a055e479bbfd04418b480e”
source=”Wikipedia; Library of Congress”
caption=”President Jimmy Carter in a photograph taken on January 31, 1977.”
credit_href=”https://commons.wikimedia.org/wiki/File:Jimmy_Carter_Crop.jpg”
]
[/slideshow]