Mankind has been looking up at the stars for centuries, wondering what lies out there
in deep space, and if there are other civilizations like ours
that exist. We started using telescopes, but when that wasn’t enough, advanced technology
led to the creation of space probes so we could get a better look at our solar system and beyond.
The Voyagers are two of the most iconic spacecraft mankind has ever invented and launched into space,
and they’re still out there hurtling through the cosmos.
And after 7 months of silence the amazing Voyager 2 once again called back home top Earth.
Now get ready to find out more about these amazing spacecraft, the incredible things they found,
where they are now, how far they have traveled away from us, and what is in their future.
[LOGO]
In the history of spaceflight, only five spacecraft launched by humanity have the momentum
to leave our solar system. The Voyagers are two of these spacecraft, and they ended up discovering
more than we thought they would, and have lasted a lot longer than NASA predicted. We think they’re
just not given the love they deserve, so we’re going to tell you some really interesting things
about them you might not know, what they have discovered, and where they are headed.
Officially approved back in 1972, the Voyager project was originally called
Mariner/Jupiter Saturn, and the probes were previously named Mariner 11 and Mariner 12,
but NASA decided to change the name because these two new probes had progressed sufficiently beyond
that of the Mariner spacecraft family. In other words, they were much more advanced.
Now, while we’re on the subject, it’s really interesting to look at the technology and hardware
of these vintage probes. These spacecraft were launched an astounding 44 years ago.
Voyager 2 on August 20, 1977, and Voyager 1 2 weeks later on September 5, 1977. This was at
a time when important advances were made in the science of gravity-assisted orbital trajectories,
or in other words; the ability for spacecraft to use the gravity of a nearby planet to give it a
large boost in velocity as long as the spacecraft follows the intended or mapped out orbit.
First, let’s talk about the computers, which are identical in both spacecraft. Each computer system
aboard the Voyager spacecraft is dual-redundant, meaning there was two of everything in the event
one computer system should fail. The computers aboard the voyager probes each have just 69.63
kilobytes of memory, total. That’s only enough space to store an average sized JPEG photo file.
Each of the space probe’s scientific data is encoded on old-fashioned digital 8-track tape
machines. However, they aren’t anything like your grandfather’s 8-track stereo in his classic muscle
car. There aren’t any physical examples that exist, or anything sitting in a museum somewhere,
but we do have a photo of it. Yes, this is the data tape recorder that
was subcontracted to Lockheed and manufactured by Odetics Corp for both Voyager spacecraft.
It could record data at two different speeds: 115.2 kbps
and 7.2 kbps [kilobytes per second]. Playback topped out at a much slower 57.6 kbps,
with 33.6, 21.6, and 7.2 kbps being options as well. Exactly what the magnetic tape was made of,
and what secrets were used to keep it from degrading in the harsh environment of space
is unclear. Whatever those secrets are, they seem to have worked because the DTR’s in both
spacecraft performed flawlessly from their launch, through the entire Grand Tour mission, and even
the extended mission that set both of these spacecraft on a course out of our solar system.
The Voyager spacecraft computers are capable of executing about 81,000 instructions per
second. Your smartphone that you might be watching this video on is probably around
7500 times faster than that! They transmit data back to Earth at 160 bits per second.
To give you an idea of that speed, if you used this same connection,
it would take you around 8.5 years to download a 5gb movie from netflix.
But probably the most interesting thing aboard each spacecraft,
the Voyagers have something no other spacecraft have; a golden phonograph
record. These two gold-plated copper discs contain 115 analog-encoded photographs,
greetings in 55 languages, and a 12-minute montage of sounds on Earth, and 90 minutes of music. These
were made in the event an extraterrestrial civilization ever finds one of the probes.
Powering each spacecraft are three plutonium dioxide radioisotope
thermoelectric generators or RTGs mounted at the end of a boom.
Each probe was fitted with 11 different scientific instruments,
which if we explained in detail would take easily over an hour.
(narrator - do not narrate) (video editor - put on screen as text)
[1. Imaging Science System (ISS) 2. Ultraviolet Spectrometer (UVS)
3. Infrared Interferometer Spectrometer (IRIS) 4. Planetary Radio Astronomy Experiment (PRA)
5. Photopolarimeter (PPS) 6. Triaxial Fluxgate Magnetometer (MAG)
7. Plasma Spectrometer (PLS) 8. Low-Energy Charged
Particles Experiment (LECP) 9. Plasma Waves Experiment (PWS)
10. Cosmic Ray Telescope (CRS) 11. Radio Science System (RSS)]
Instead, let’s look at a few of the exciting things the Voyager probes found,
and the images captured during their missions using these instruments.
Both spacecraft have been traveling along different trajectories and at
different speeds. Voyager 1 is traveling faster, at a speed of about 61,155.07
kilometers per hour [38,000 mph], compared to Voyager 2's velocity of
56,327.04 kilometers per hour [35,000 mph]. (narrator - give a 2 second pause between the
planets so we have some time to show some images) Voyager 1 captured incredible images of Venus,
Jupiter, Neptune, Saturn, and Uranus. Voyager 1 also captured an incredible
image of Jupiter’s moon Io where a volcano was seen erupting from the surface.
It was the first time ever that an active volcano had been seen elsewhere in the solar system.
But the most famous image Voyager 1 captured was of the Earth, or what is famously known
as The Pale Blue Dot taken February 14, 1990 at a distance of 6 billion
kilometers [3.7 billion miles] away, and inspired the title of Carl Sagan’s book; A Pale Blue Dot:
A Vision of the Human Future in Space.
Voyager 2, on the other hand, began transmitting images of Jupiter on April 24,
1979 that were put together to show a time-lapse movie of the gas giant's atmospheric circulation,
including the infamous Great Red Spot storm that is three-times the diameter of Earth.
Voyager 2 was able to do this because it made closer passes to Jupiter and the Jovian moons.
On August 25, 1989, Voyager 2 flew by Triton, one of Neptune’s moons. The Voyager 2 data was used
to construct this video of its exciting encounter, and showed us Jupiter as we had never seen before.
Between them, Voyager 1 and 2 explored all of the giant planets of our outer solar system,
and 48 moons, a unique system of rings, and the magnetic fields of each of the outer planets.
But this wouldn’t be all Voyager 1 and 2 would discover,
as you’re about to find out. In fact, they would encounter something far
more mysterious and unknown, and something they weren’t even designed for.
Voyager 1 entered interstellar space on August 25,
2012, and was the first human-made object to do so,
As Voyager 1 left the heliosphere, which is a giant bubble of charged particles that the
sun blows around itself, the probe recorded a 1,000-fold drop in heliosphere particles
and a 9% increase in galactic cosmic rays that come from outside the solar system.
Since flying into interstellar space, Voyager 1 has sent back some information
about the conditions in this dark zone of the universe. One of those discoveries is that the
cosmic radiation out there is very intense and demonstrates how charged particles from the sun
interact with particles emitted by other stars, and how this bubble of charged
particles protects everything inside our solar system from those deadly cosmic rays.
On November 5, 2018, Voyager 2 became the second spacecraft ever to enter interstellar space when
the probe registered a sudden decrease in solar wind particles emanating from the Sun,
and at the same time, it also experienced an increase in galactic cosmic rays
and the strength of the interstellar magnetic field.
Voyager 1 has continued to astound engineers when in December 2017, it successfully used its
backup thrusters to orient itself so that we could communicate with it back here on Earth.
Those thrusters hadn’t been used since November 1980 during Voyager
1’s flyby of Saturn. How’s that for reliability?
The Voyager probes are always sending out a signal. Each probe has a 22.4-watt radio
transmitter, which is about equivalent to a tiny refrigerator light bulb.
The mind blowing thing is that by the time its signal reaches us, the power has been reduced to
roughly 0.1 billion-billionth of a watt! It’s so small that NASA has to use its Deep Space
Network array of giant radio antennas together which consist of three facilities spaced apart
from each other around the world; the Madrid Deep Space Communications Complex - The Canberra Deep
Space Communication Complex in Australia, and the massive 70-meter [230-foot] antenna at the
Goldstone Deep Space Communications Complex in Barstow, California.
The sensitivity of NASA's deep-space tracking antennas located around the world
is truly incredible. These huge antennas must capture Voyager information from a
signal so weak that the power striking the antenna is only 10 exponent -16
watts [1 part in 10 quadrillion]. A modern electronic digital watch
operates at a power level 20 billion times greater than this incredibly feeble level.
And we’re not done talking to the Voyagers just yet. On October 29,
2020, mission operators sent a series of commands to Voyager 2 after a long 7-month silence.
The spacecraft had been flying solo while the 70-meter antenna at the Goldstone Deep Space
Communications Complex was being repaired and upgraded. The amazing thing is that after all
these years and the fact that Voyager 2 is in interstellar space, it returned a
signal confirming it had received the call and executed its new commands without any issues.
As of January 2022, Voyager 1 is 23.3 billion kilometers from
Earth [14.5 billion miles] and Voyager 2 is 19.3 billion kilometers [12 billion miles] from us.
Most of the instruments have been shut down on both of these probes in order to conserve power.
Voyager 1 is headed in towards the constellation Ophiuchus, and in the year 40,272 AD,
it will come within 1.7 light years of an obscure star in the constellation
Ursa Minor called AC+79 3888. In about 40,000 years, Voyager 2 will come within
about 1.7 light years of a star called Ross 248 which lies in the constellation of Andromeda.
But sadly, and much sooner than this, we’ll lose contact with both of these spacecraft for good,
and they’ll pass silently into the interstellar void. It would be interesting if one day,
in the very far and distant future, a civilization out somewhere out there finds a Voyager and learns
to power it back up. If so, that primitive hardware might spin back to life one last time.
Stay tuned here to see if the Voyagers find something new,
and to keep up with all the exciting things happening in our universe. Thanks for watching!