You have to start at the beginning I think.
Voyager, as a program, was conceptualized in the 60’s as a “Grand Tour” of the outer planets of our solar system. JPL scientist Gary Flandro pointed out that the unique alignment of the planets in the late 70’s would mean that a single spacecraft could use gravity assists to loop it’s way from one giant to the next, capturing on camera our distant neighbors…. for the first time. They were originally supposed to be a continuation of the Mariner missions but they were given a new designation and purpose.
Voyager 1 and Voyager 2. They arrive at Cape Canaveral, are mounted aboard their launch vehicles and rolled out to the pad.
It’s August 20th, 1977 Voyager 2 is launched from Cape Canaveral, LC-41 atop a Titan III-Centaur rocket. On September 5th, 1977 Voyager 1 joins its twin sister on the journey to the stars.
On September 18th, 1977, the Voyager 1 craft turns her camera back towards earth from a distance of 7.25 million miles and snaps a picture of Earth and the moon; bright crescents in the dark abyss. It’s the first time a spacecraft has taken a picture of our home planet like this. But that’s what Voyager is, a mission of firsts. On December 10th, 1977: Voyagers 1 & 2 enter the Asteroid Belt together.
Because of their launch trajectories, their mission manifests, and goals… on December 19th, 1977, despite launching later, Voyager 1 overtakes Voyager 2 in the Asteroid Belt.
The Asteroid belt stretches between Mars and Jupiter, the first real obstacle that the probes will face in their mission. Twelve spacecraft have navigated the Asteroid Belt and the distribution of asteroids within the belt makes it unlikely that a collision will occur (unless planned).
While navigating the Asteroid Belt in 1978, Voyager 2’s primary radio receiver fails, the remainder of the mission is flown using the backup. However, a failed capacitor in the receiver meant that transmissions could only be sent if they were at the right frequency…which could be affected by the rotation of the earth due to the Doppler effect. For every transmission after this engineers would have to calculate the specific frequency for the signal so that the spacecraft could receive it.
January 6, 1979, Voyager 1 starts the Jupiter observation phase and on April 25, 1979 Voyager 2, playing a perpetual game of catch up follows behind. Knowing that images and data are arriving back from the Voyager crafts, scientists begin spending the night in JPL or in their cars, unwilling to stray far in case the downlink happens and they aren’t on shift. The press fill the auditorium past capacity. This is our closest pass to Jupiter and the Jovian system. With this flyby we learn about volcanic activity on Io, the first time volcanoes had been observed on another planet within our solar system. We learn about Jupiter’s rings, never before seen by us. We fly by Ganymede, Callisto, Amalthea, and Europa. There are stars in our eyes.
August 22, 1980 Voyager 1 approaches Saturn and we see the planet like never before. The rings exhibiting spoke features that we never observed from the ground, more glorious this close up than could have been imagined. Aurora activity at the poles, an upper atmosphere of helium, and the rest hydrogen; winds at Saturn’s equator blow at almost 1,100mph. Voyager 1 also has the job of flying by Titan to study it’s atmosphere, a unique feature among moons in the outer planets. We use instrumentation to determine that lakes of hydrocarbons could exist on the surface.
Because of the trajectory needed to send Voyager 1 to study Titan, Voyager 1 will not continue to the ice giants like its sister ship. Voyager 1 has a different mission.
As of December 14, 1980, Voyager 1 begins its extended mission. We part ways for the moment, but it’s not over, not by a long shot.
June 5, 1981 Voyager 2 makes the approach to Saturn and because there isn’t the expectation of a close up attempt at Titan, Voyager 2 has time to take in the other moons and measure things like the temperature fluctuations on Saturn and atmospheric density profiles. Together with the mission data from Voyager 1 we’re painting a robust portrait of our distant neighbors.
After the Saturn flyby, the camera platform on Voyager 2 locks up and puts the rest of the mission in jeopardy. The ground crews have to troubleshoot the issue but finally determine the work around and just in time… we have somewhere very important to be.
November 4, 1985, Voyager 2 begins the Uranian portion of the mission. We have come to a planet never before explored by man and lay eyes on 11 previously undiscovered moons. We study the axial tilt of the planet, the rings and the 17 hour long day. The rings include two that have never been studied before and their origins are unknown. Scientists on the ground hypothesize that maybe they weren’t formed together, the rings maybe formed in their own event at a later time. Scientists who have spent a lifetime behind telescopes on earth, buried in books, are on the edge of their seats as this little craft millions of miles away tells them a new story; illuminates their field brighter than they could have ever dreamed.
During the downlink of images from the Uranian system visit, JPL scientists gather around their computer screens, watching as their colleagues at Cape Canaveral send up the Space Shuttle.
It’s January 28, 1986.
In the documentary, “The farthest: Voyager in space” one of scientists says on one screen she was watching Voyager send back photos from Uranus and on the other, she was watching Challenger disintegrate over the Atlantic ocean.
While the newscasters didn’t know what to say, didn’t know what was going on at first, the scope of what they had just witnessed, JPL knew.
When they go to make the press conference, the room is empty, seats unfilled. It’s a stark reminder of the cost of discovery and advancement, that even when we think we have it all figured out, maybe we don’t.
Voyager flies on.
June 5, 1989 is the start of the Neptunian observation phase. Voyager 2 learns about Neptune’s rings, about 6 new moons, and about the great dark spot. Hubble would later observe the spot being gone and scientists believe that this spot was originally a window through the upper atmospheric methane clouds that cloak Neptune’s surface.
This is it.
October 2, 1989, Voyager 2 begins its Interstellar Mission.
February 14, 1990, Voyager 1 turns the camera back, and takes the Solar System Family Portrait. From 3.7 billion miles away, Voyager 1 takes a series of photographs that when combined together create an image of our neighborhood that we have never put together before, have never been able to. Most importantly, for the first time, we see ourselves. Not from the alien habitat of the Moon, our graceful curving blue marble rising in the background, but Earth as we’ve never seen her before. Out of focus, small, distant and insignificant.
The Pale Blue Dot.
“That’s here. That’s home. That’s us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives………Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves. It is up to us. It’s been said that astronomy is a humbling, and I might add, a character-building experience. To my mind, there is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly and compassionately with one another and to preserve and cherish that pale blue dot, the only home we’ve ever known.”
Carl Sagan, Cornell University October 13, 1994
It’s official, with their mission objectives complete, the Voyager spacecraft are pointed towards the edge of the heliosheath and we wait.
We’re going to talk about Voyager 1, it went first, broke new ground, led the way. In 2010 commands were sent to Voyager 1 to check the solar wind, and the craft re-oriented, rolling itself in space as we spoke to it from our mote of dust in a sunbeam. After it was reported that the movement had been a success, Voyager 1 reoriented and pointed itself back towards Alpha Centauri – its guidestar.
In 2011, the first Lyman-alpha radiation was detected by the craft – Lyman-alpha radiation from the Milky Way. We had detected it from other galaxies before, but not the Milky Way because of interference from the Sun.
In 2012 it is believed that Voyager 1 passes the heliopause and enters interstellar space. The first human-made object to do so.
There is a struggle in 2017 when on board jets for Voyager 1 fail, leaving us in the sticky position of possibly losing contact with the probe earlier than we believed. In a last ditch effort at saving it, NASA fires up secondary thrusters that haven’t been used for decades. It’s the long shot, but it’s all they have.
With their hearts in their throats, they send the command and wait…. And Voyager 1 responds, the TCM turning on as if they hadn’t been off a day. The craft reorients and the movement of the antenna back towards us means we have a couple more years with Voyager 1.
We’re so lucky.
Voyager 2 is hot on the trail of its sister, chasing Voyager 1. It was thought that Voyager 2 would cross through the heliopause in 2016 but a Queen is never late, she arrives exactly when she means to and everyone else is just early.
December 10, 2018, NASA announces that Voyager 2 has joined its twin across the border into interstellar space and both our craft are transmitting home. It’s believed that Voyager 2 will remain online into 2025, sending home data and information about its voyage.
In a few hundred years the spacecraft will pass into the Oort cloud which takes 30,000-40,000 years to cross. After that they are destined to wander the Milky Way forever. Eventually Voyager 1 will pass within 1.6 light years of Gliese 445. If undisturbed for 296,000 years, Voyager 2 will pass within 4.3 light years of Sirius; they will be closer to these alien stars than their own home star, the sun.
Maybe Voyager is our love letter to the universe, it has all the best parts of ourselves engraved on a golden record, and if found will tell the finder about those things. Maybe it was sent out to be a message in a bottle to the void, but I think we ended up getting a message back to ourselves in the process. If we value these things enough to put them on a record into the abyss, why don’t we value them enough to protect them here, on our fragile oasis?