Even after 47 years, the achievements of the Voyager 1 and 2 probes continue to inspire people to dream bigger and ponder the mysteries of the Universe
Host | Matthew S Williams
On ITSPmagazine 👉 https://itspmagazine.com/itspmagazine-podcast-radio-hosts/matthew-s-williams
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Episode Notes
Someday, they may become the first ambassadors for humanity, encountering another civilization, or could be retrieved by future generations as the ultimate "time capsule"!
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Resources
NASA - Voyager: https://voyager.jpl.nasa.gov/
The Planetary Society - The Voyager Missions: https://www.planetary.org/space-missions/voyager
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For more podcast Stories from Space with Matthew S Williams, visit: https://itspmagazine.com/stories-from-space-podcast
The Grand Tour: The Legacy of the Voyager Probes | Stories From Space Podcast With Matthew S Williams
[00:00:00] The authors acknowledge that this podcast was recorded on the
traditional unceded lands of the Lekwungen peoples. Hello, and welcome back
to Stories from Space. I'm your host, Matt Williams. And today we have a very
special episode which pays tribute to the Voyager program and the two probes,
Voyager 1 and Voyager 2.
And this special tribute episode is inspired in large part by the fact that recently,
on April 18th, 2024, NASA mission controllers indicated that contact had been
restored with the Voyager 1 probe. Which means both probes are now back in
touch with NASA's Deep Space Network. This makes Voyager 1 and 2 NASA's
longest serving missions, as well as the farthest to ever travel from Earth.
And while they're not the only missions in interstellar space, They're currently
being five. They've been there far longer than New Horizons, and remain active
[00:01:00] unlike Pioneer 10 and 11. Information, pictures, and data they
returned on the outer planets is not only groundbreaking, but in many cases, has
yet to be repeated.
The Voyager missions were originally conceived as part of the Mariner
program. In the original architecture, NASA's Jet Propulsion Laboratory
planned to send four spacecraft to the outer solar system to conduct what they
called the Planetary Grand Tour program, which they had slated for the late 60s
and early 70s.
These probes would work in pairs of two, and would explore all of the outer
planets of the solar system. Whereas two would visit Jupiter, Saturn, and Pluto,
the other two would visit Jupiter, Uranus, and Neptune. The missions would
also take advantage of an alignment of the outer planets that occurs every 175
years.
This alignment would provide gravitational assists, allowing the missions to
pick up velocity as they traveled farther out to the edge of the solar system, and
eventually [00:02:00] achieving escape velocity to become the first missions to
explore interstellar space. However, due to the high cost of the program, and the
changing budget environment at NASA in the post Apollo era, the original plan
was scrapped.
In its place, elements of the Grand Tour program were merged with the new
Voyager program. Which called for two probes, which would explore twoseparate trajectories established by nasa, which included the JST trajectory and
the JSX, whereas the JST trajectory would bring the Voyager one probe past
Jupiter and Saturn with a quick fly by of Saturn's largest moon titan.
JSX would offer greater flexibility and allow the Voyager 2 probe to fly past
Jupiter and Saturn, then continue onto Uranus and Neptune. This plan scrapped
a possible flyby of Pluto, which would not be visited until the New Horizons
probe buzzed the system in July of 2015. The Voyager probes were [00:03:00]
equipped with an advanced suite of scientific instruments.
Which included an imaging science system consisting of two cameras, one
narrow angle and one wide angle, that would provide images of Jupiter, Saturn,
and other celestial objects along the two prompts trajectories. They also came
equipped with a series of magnometers, spectrometers, radio science
instruments, and others.
These would allow the probes to determine the atmospheric composition, and
measure the temperature profiles, thermal properties, and radiation of Jupiter,
Saturn, Uranus, and Neptune, as well as to gauge the size of the particles in
Saturn's rings. The magnetometers would also be used to measure the magnetic
fields of the outer planets.
As well as their interaction with solar wind. The probe's magnetometers were
also intended to measure the interplanetary magnetic field out to the solar wind
boundary, and its interaction with the interstellar magnetic field and beyond.
What's more, the Voyager [00:04:00] probes carry a special payload. known as
the Voyager Golden Record.
The Voyager 2 probe was the first to launch in August of 1977. Voyager 1
launched 16 days later, in September of 1977, following Voyager 2's path
towards Jupiter. Voyager 1 was the first to arrive in January 1979, followed by
Voyager 2 in July. During their stay in the Jovian system, The two probes
collected images and data that revealed unknown details about Jupiter and many
of its larger moons.
In particular, the Galilean moons Io, Europa, Ganymede, and Callisto. This
included four months of observations of the moon Io, Jupiter's innermost
Galilean moon, in which the two probes monitored continuous volcanic activity
on the surface. This was the first time active volcanoes had been viewed beyond
Earth.NASA and led to theories about how Io's interaction with Jupiter's [00:05:00]
powerful gravitational field caused internal heating in the moon, producing
large lava flows that continuously erupted on the surface. Voyager 1 was also
responsible for taking pictures of Jupiter's Great Red Spot that led astronomers
to conclude that it was a huge cyclonic storm.
Voyager's cameras also picked up unusual features on Ganymede, which
included grooved terrain, which suggested that the surface experienced a form
of tectonic activity. But in this case, ice was involved, rather than a rocky
mantle. Voyager 1 was also responsible for detecting Jupiter's ring system.
Which the Voyager 2 probe would go on to take the first images of.
Previously, astronomers believed that only Saturn among the gas giants had a
ring system. But based on the Voyager probe's results, they came to understand
that all gas giants have a ring system, which are generally composed of lower
albedo [00:06:00] material, which is far less reflective, and therefore much
harder to see with Earth based telescopes.
The Voyager 1 and 2 probes also discovered something very interesting about
the moon Europa, the moon that orbits between Io and Ganymede. Like
Ganymede, this included features known as chaos terrain, characterized by
patches of ice that are cratered and rugged, existing alongside patches of
smooth, younger ice.
This was interpreted as evidence of possible endogenic surfacing, where
material is exchanged between the interior and the surface. These and other
lines of evidence pointed towards the possible existence of an ocean in Europa's
interior, one that existed beneath the icy crust at the core mantle boundary.
Combined Jupiter's gravity caused the moon's interior to flex, much like Io's,
This would lead to geothermal heating, but instead of producing magma, it
would [00:07:00] maintain a warm water ocean. Based on the way geothermal
vents and deep sea fissures are associated with life here on Earth, it also led to
speculation that this ocean could support extraterrestrial lifeforms.
Which could range from simple microbial organisms to larger aquatic
organisms. Scientists still don't know, but are hoping to get a better idea with
missions like Europa Clipper in the near future. Next, the probes moved on to
Saturn, where they studied its fabulous rings, discovered new moons, and Titan,
with a close flyby.Voyager 2 was the first to enter the system in August of 1980, while Voyager 1
followed 3 months later in November. Among their discoveries, the probes
charted the complex structure of Saturn's rings, which consisted of smaller rings
embedded between larger ones. And also measured their composition. In
particular, they noted that the [00:08:00] rings contained more water ice than
previously thought.
Together, the probes discovered Atlas, Prometheus, Pandora, Kephas, and
Iapetus. Satellites that had previously eluded detection. They also confirmed
that some of these moons acted as shepherds, keeping the material in line in
some of Saturn's narrow rings. And images taken of the South Pole, once
stitched together by mission controllers back at Earth, revealed Saturn's
hexagonal shaped weather feature, which remains a source of fascination and
mystery for astronomers, and has since been imaged extensively by the Cassini
Huygens mission.
Last, but certainly not least, both probes revealed some surprising things about
Saturn's largest moon, Titan, and its relatively small, but very significant moon,
Enceladus. This included the fact that Enceladus had a highly reflective surface
that also appeared very young, in the sense that it lacked [00:09:00] impact
craters.
Combined with the fact that Enceladus orbited within Saturn's E ring, this led
scientists to conclude that Enceladus was responsible for replenishing material
in this ring. This theory would later be confirmed by the Cassini Huygens
mission, which obtained multiple images of the plume activity erupting from the
Moon's southern polar region.
Like Europa and Ganymede, Enceladus would soon be added to the list of ocean
worlds. Icy moons with interior oceans in the outer solar system. As for Titan,
while the Pioneer 11 mission had previously visited the moon in 1979, The
images and data acquired by the Voyager probes were of greater quality.
Voyager 1's trajectory was also designed to provide the optimal Titan flyby.
This allowed the two spacecraft to determine the density, composition, and
temperature of Titan's atmosphere. These confirmed that Titan's hazy
atmosphere, which obscured [00:10:00] its surface features, was largely
composed of nitrogen.
This makes Titan the only body in the solar system, other than Earth, to have a
dense nitrogen atmosphere. In addition, the probes noted large quantities of
hydrocarbons, particularly methane and ethane. The probes data also hinted atthe possible existence of liquid methane lakes on the surface. This, too, would
be confirmed by the Cassini Huygens mission, and indicated that Titan had
something akin to a hydrological cycle like Earth, existing in the form of vapor
in our atmosphere, water in our oceans, and precipitation in between.
The solvent involved was methane and other hydrocarbons. At this point, the
Voyager 1 and 2 probes departed from each other and followed separate
trajectories that would eventually lead them both to the outer solar system.
Meanwhile, the Voyager 2 probe continued on to Uranus and Neptune. In
[00:11:00] January of 1986, it passed through the Uranian system and became
the first probe to image its cold dark rings.
The images it acquired also revealed 11 new moons, while its magnetometer
studied Uranus's magnetic field and learned of its unique properties. In essence,
Uranus's magnetic field is tilted towards its own equator and towards the sun,
meaning that one pole will experience perpetual sunlight and the other perpetual
darkness for many years at a time.
In August of 1989, the Voyager 2 probe became the first to visit Neptune. In
addition to capturing images of Neptune's rings, Voyager 2 also discovered six
new moons. And also captured the first close up images of Triton, Neptune's
largest moon. These revealed what scientists referred to as cantaloupe rine
terrain, consisting of rough patches that were pockmarked with crater like
features.
Voyager 2 also became the first [00:12:00] probe to capture images of Triton's
impressive geysers, indicating that Triton also experienced cryovolcanism.
Suggesting that it, too, may have an interior ocean. Last but not least, Voyager 2
captured images of the Great Dark Spot, a massive rotating storm in Neptune's
southern hemisphere, similar to Jupiter's Great Red Spot.
Meanwhile, the Voyager 1 probe conducted the Blue Dot Campaign. This took
place on February 14, 1990, and was suggested by Carl Sagan as part of a solar
system family portrait. Rotating its camera back towards Earth, Voyager 1 was
able to capture an image of Venus, Earth, Jupiter, Saturn, Uranus, and Neptune
as faint points of light around the Sun.
From this portrait, the best known image of Earth ever taken was produced,
known as the Pale Blue Dot. This image inspired Carl Sagan to consider
[00:13:00] the fragility and uniqueness of our planet. It also inspired him to
write the book of the same name, in which he said, Consider again that dot.
That's here.That's home. That's us. On it, everyone you love, everyone you know, everyone
you ever heard of, every human being who ever was, lived out their lives. The
aggregate of our joy and suffering. Thousands of confident religions, ideologies,
and economic doctrines. Every hunter and forager. Every hero and coward.
Every creator and destroyer of civilization. Every king and peasant. Every
young couple in love. Every mother and father. Hopeful child, inventor and
explorer, every teacher of morals, every corrupt politician, every superstar,
every supreme leader, every [00:14:00] saint and sinner in the history of our
species lived there on a mote of dust suspended in a sunbeam.
The earth is a very small stage in a vast cosmic arena. Think of the rivers of
blood spilled by all those generals and emperors, so that in glory and triumph
they could become the momentary masters of a fraction of a dot. Think of the
endless cruelties visited by the inhabitants of one corner of this pixel on the
scarcely distinguishable inhabitants of some other corner.
How frequent their misunderstandings. How eager they are to kill one another.
How fervent their hatred. Our posturings, our imagined self importance, the
delusion that we have some privileged position in the universe, [00:15:00] are
challenged by this point of pale light. Our planet is a lonely speck developing
cosmic dark.
In our obscurity, in all this vastness, there is no hint. The Earth is the only world
known so far to harbor life. There is nowhere else, at least in the near future, to
which our species could migrate. Visit? Yes. Settle? Not yet. Like it or not, for
the moment, the Earth is where we make our stand. It has been said that
astronomy is a humbling and Character building experience.
There is perhaps no better demonstration of the folly of human conceits than
this distant image of our tiny world. [00:16:00] To me, it underscores our
responsibility to deal more kindly with one another and to preserve and cherish
the Pale Blue Dut, the only home we've ever known. Carl Sagan also played an
important role in another major aspect of the Voyager missions, which were the
Golden Records.
These records were designed by a select committee chaired by Carl Sagan.
Contents of the record includes pictures and sounds of Earth, as well as
symbolic directions on the cover for how to play the record, and where the solar
system is located in our galaxy. Much like the Pioneer plaques that adorned
their predecessors, the Pioneer 10 and 11 probes, The purpose of the Golden
Record was to act as an interstellar message to an advanced civilization thatmight come upon it someday, or as a time capsule to future generations of
humans, who may, in the course of exploring neighboring star systems, come
upon this ancient piece of [00:17:00] technology Which could teach them a
great deal about the late 20th century and the civilization that built and sent the
probes out into space.
While the two probes are now in the interstellar medium, it will take several
thousand years for them to reach the nearest star systems. In 40, 000 years,
Voyager 1 will pass within 1. 6 light years of AC plus 79 3888, a star in the
constellation of Camelobirdalis. In that same time, Voyager 2 will pass within
1.
7 light years of Ross 248. About 296, 000 years from now, it will pass within 4.
3 light years of Sirius, the brightest star in the sky. Today, some 47 years after
they were first launched, Both probes are still functioning and relaying vital
information back to Earth to ensure that the probes can keep transmitting.
NASA implemented a new power strategy where a small reservoir backup
power that had been set aside as part of an [00:18:00] onboard safety
mechanism Those now being used over time, perhaps will be powered down
further by switching off one instrument after another. At present, NASA
estimates that the Voyager 1's extended mission will continue to return science
data until at least 2025, with a maximum lifespan of until 2030.
By 2036, its radioisotope thermoelectric generator may not supply enough
electrical power to keep returning engineering data. Meanwhile, the Voyager 2
spacecraft is expected to be able to return data via the Deep Space Network well
into 2036. As for when the mission will end, that's difficult to say. It is ongoing
at this point, and the scientific returns will diminish the farther the probes get
away from us, and shall also impede NASA's efforts to initiate fixes and
corrections.
Nevertheless, in their time, the Voyager probes have left an unparalleled legacy.
As noted, the [00:19:00] Pale Blue Dot campaign produced one of the best
known pictures of Earth. The inspiration it provided to Carl Sagan to write his
book of the same name, echoed what Frank White said in his book, The
Overview Effect, about how viewing Earth from space can cause a cognitive
shift.
where the individual begins to understand how fragile and precious Earth's
ecosystems are, and how all life on Earth is connected, irrespective of national
boundaries. The information they revealed about Jupiter's systems of moonsalso inspired the subsequent installments in Arthur C. Clarke's Space Odyssey
series, which focused on the possibility of life within Europa's icy shell, and
how that life could evolve further.
If Jupiter were converted into a second sun. They also inspired the Grand Tour
series of famed science fiction author Ben Bova, where each book in the series
detailed a settlement in a certain part of the [00:20:00] solar system. Voyager
probes were also a plot device in Star Trek The Motion Picture, where the
probes eventually encountered an alien entity that began to travel to Earth in
order to find its makers.
Most importantly of all, Voyager missions inspired NASA and other space
agencies to mount follow up missions to study the outer planets. These include
the Galileo and Juno orbiters, both of which studied Jupiter and its systems and
moons exclusively. Whereas the Galileo mission studied Jupiter and its moons
between 1995 and 2003.
The Juno probe commenced science operations around Jupiter in 2016, and is
expected to remain in operation until September 2025. It also includes the
Cassini Huygens mission, which entered the Saturn system in 2004, and
remained in operation until 2017. And then you have the New Horizons
mission, which became the very first [00:21:00] spacecraft to visit Pluto on July
14th, 2015, and subsequently visited a Kuiper belt object known as Arrokoth on
January 1st, 2019.
In the near future, NASA, European Space Agency, and others hope to pick up
where the Voyager probes and their successors left off. This includes the
European Space Agency's Jupiter Icy Moons Explorer, or JUICE, which
launched on April 14th, 2023, and will reach the Jupiter system by 2031. This
probe will conduct extensive studies of Ganymede, in order to learn more about
its composition, surface, and its interior ocean, and will also conduct a flyby of
Europa.
On October 10th of this year, JUICE will be joined by the Europa Clipper
mission, which will surpass it in space and reach Jupiter by 2030, whereupon it
will conduct extensive investigations of Europa, [00:22:00] examine its surface
and interior, and attempt to address the fundamental question of whether or not
there could be life there.
Proposals have also been made for an Enceladus orbiter, which would pick up
where the Cassini probe left off by flying directly through the plumes emanating
from its southern polar region and examining them for biosignatures. There arealso numerous missions on behalf of NASA, the China National Space Agency,
the European Space Agency, and others.
to send additional spacecraft to the outer solar system. These would not only
investigate Uranus and Neptune, which are poorly studied compared to Saturn
and Jupiter, but also other potential ocean worlds. These include Titan, Saturn's
largest moon, but also Deon, Mimas, and Miranda in the Saturn system, Ariel,
Titania, Umbriel, and Oberon in the Uranian system, Triton in the Neptune
system, As well [00:23:00] as Pluto and Charon.
At this point, it's impossible to know what the ultimate fate of the Voyager
probes will be. But one thing is clear. Long after they ceased operation, they
will continue to drift through the cosmos, and could very well become the first
messengers from the solar system to ever make contact with another advanced
species.
Or, possibly, they could become time capsules, which future humans will
stumble upon, possibly centuries or even millennia from now. What they will
make of these missions, whether or not they will even recognize them for what
they are, and how future generations will interpret the content of the golden
records, and how will these reactions compare to those of an advanced
extraterrestrial species?
These are all very fascinating questions. And they helped to establish the
purpose of the Voyager probes and their ongoing mission out into the Milky
Way. At this point, one can only imagine. But [00:24:00] to paraphrase another
great science communicator, Arthur C. Clarke, the truth, as always, will be far
stranger than fiction.
In the meantime, thank you for listening. I'm Matt Williams, and this has been
Stories from Space.