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[♩INTRO]
It might seem like we know a ton about the
solar system, but we’ve really only learned
most of what we know in the last 60 years
or so.
Before that, we didn’t even know much about
our closest neighbors: Mercury, Venus and Mars.
And then the Mariner program came along.
When you think about space exploration in
the 1960s, the Apollo landings are probably
the first things that come to mind.
But the Mariner probes made huge leaps in
how we understand the solar system today -- and
especially how we understand Mars.
Starting in 1962, the Mariner missions explored
the inner solar system, in NASA’s first
program that resembled what we think of today
as planetary science.
There were ten missions in all, with only
three failures — which was pretty impressive
for early spaceflight.
One of the reasons the Mariner program was
so successful was because of a new feature
called three-axis stabilization.
It allowed engineers to control the spacecraft’s
orientation in three dimensions, so scientists
could point its instruments wherever they
liked -- which was important for getting those
older cameras to take clear pictures.
Other spacecraft were stabilized by spinning
like a top, which could be useful in some
situations — just not this one.
It also helped that NASA’s Jet Propulsion
Laboratory built each spacecraft with a common design.
The electronics were kept in a central hexagonal
or octagonal housing called the “bus,”
with pairs of solar panels attached to the
sides.
Reusing basic pieces allowed them to refine
components in an era when more than half of
all missions could fail.
Which is what happened to Mariner 1 in 1962.
But later that year, its twin, Mariner 2,
visited Venus and became the first spacecraft
to fly past another planet!
Among other things, it taught us that Venus
doesn’t have a powerful magnetic field like
Earth does.
Then, two years later, with Mariner 3, NASA
set its sights on Mars … but its solar panels
didn’t work, so the mission failed.
Thankfully, everything went okay for Mariner
4, and in 1965, it became the first spacecraft
to visit Mars!
It sent back only 5.2 million bits of data,
or about 650 kilobytes, which is probably
less than it takes to store half a second’s
worth of the video you’re watching right now.
But at the time, that was enough to include
about 20 images, plus other observations,
like surface temperature and pressure.
Along with the news that Mars also doesn’t
have much of a magnetic field.
And Mariner 4 properly disproved an idea that
had been popular decades earlier: that Mars
was crisscrossed by a series of enormous canals,
which were built by an advanced civilization
in a last-ditch effort to save their dying
home.
By the time the Mariner missions launched,
most scientists didn’t agree with that,
but other people still believed it.
And with no sign of canals or other evidence
of life, those first images were also proof
that Mars was a dead world, at least on a
large scale.
The computers in the ‘60s didn’t transmit
or process data very quickly, though, so it
took a while for those pictures to pop up
on computers back home.
It took so long that by assigning colors to
the numbers Mariner sent back, the first image
from Mars was colored by hand faster than
it could be rendered on screen!
So, yeah, the very first pictures we saw from
a Mars probe were essentially coloring pages
for scientists.
Sounds like my kind of coloring book.
These days, we receive data from probes around
Mars tens of thousands of times faster, so
we’ve made plenty of progress.
A few years later in 1969, just days after
Apollo 11 landed on the moon, Mariners 6 and
7 arrived at Mars as the first successful
dual mission.
Mariner 6 launched and arrived first, which
allowed scientists to study broad images of
the surface.
The wanted a closer look at Mars’ south
pole, so they used the camera on Mariner 7
to make more detailed observations five days
later.
Sending two probes together was so useful
that NASA did this for other exploration missions,
too, like the Voyager trips to Jupiter and
Saturn.
Still, even with that one-two punch model,
Mariners 6 and 7 only managed to image about
20% of the Martian surface.
Clearly, just flying by wasn’t good enough,
so Mariners 8 and 9 aimed to fix that!
8 was destroyed in a launch malfunction, which
is a nice way of saying that after liftoff
it came right back down and landed in the
Atlantic Ocean.
But in 1971, Mariner 9 became the first spacecraft
to orbit another planet!
Nature almost threw a wrench in its plans,
though.
When the orbiter arrived, it found a global
dust storm on Mars obscuring all but the tallest mountains.
But just like Mariner 7, Mariner 9 was flexible
and could receive new tasks from Earth, so
NASA had it wait to start start seriously
taking pictures until the storm settled in January.
Whereas two Soviet probes that arrived just
weeks after Mariner 9 couldn’t accept new
input from Earth, so they took a lot of pictures
of dust.
In the end, Mariner 9 imaged 85% of the Martian
surface, taking more than 7300 pictures, which
was way more than the other missions.
It also taught us more about Mars’ atmosphere
and surface.
So this whole orbiting thing worked out great!
After the Mariner program wrapped up at Mars,
Mariner 10 went on to be the first spacecraft
to fly by Mercury.
And two missions that were originally supposed
to be Mariners 11 and 12 became Voyagers 1
and 2, which were among the first few spacecraft
to explore the outer solar system.
The Mariner design was also adapted for the
Viking orbiters that reached Mars in 1976,
and it’s been used as recently as the Cassini
mission, which is just now finishing up at
Saturn after 20 years in space.
To honor the Mariner program’s research
at Mars, the solar system’s largest canyon
system, Valles Marineris, carries their name.
Their real legacy, though, is what they taught
us about the inner solar system.
Which was a lot!
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[♩OUTRO]
