On August 5th, 2011, a rocket launched from Cape Canaveral, Florida, with a very special
payload.
It was carrying the Juno mission, named after the Roman goddess who was the wife of Jupiter,
the king of the gods.
Juno was also Jupiter’s sister.
Roman mythology was kind of the Game of Thrones of its day.
One story goes that when Jupiter surrounded himself with a veil of clouds, Juno was the
only one who could peer through and see him.
And now, NASA’s Juno probe is ABOUT to unveil more information on Jupiter when it arrives
at the gas giant on the Fourth of July.
Its mission?
To find out how the king of the planets formed.
Planets like Jupiter seem to be really common out there in the universe, so by figuring
out how they form, researchers hope to learn more about how star systems form planets in
general.
A lot of scientists think that gas giants start out as big clumps of rock, like Earth,
that then sweep up most of the gas and dust that didn’t fall into the central star.
But no one has ever seen direct proof of this kind of rocky core inside Jupiter, and it’s
still possible that it doesn’t exist -- that Jupiter is gas all the way down.
To look for evidence of the core, Juno can probe for tiny variations in the strength
of Jupiter’s gravity as it orbits -- small changes that would result from things like
big storm systems moving around a central core.
But that’s not the only thing that Juno will be doing.
The basketball court-sized spaceship is decked out with all sorts of instruments, each aimed
to tell us something different about how Jupiter formed and what’s going on under its opaque
blanket of clouds.
For example, there are ultraviolet and infrared cameras on board to study Jupiter’s two
different kinds of auroras -- each caused by a different kind of hydrogen in Jupiter’s
upper atmosphere.
There’s also a microwave radiometer, which will measure how much water is hidden in the
lower layers of the atmosphere, where no spaceship has ever been able to look.
And Juno has a bunch of different ways to measure the charged particles caught in Jupiter’s
magnetic field that fly around the giant planet at nearly the speed of light.
But best of all is JunoCam.
It’s just a regular high-definition camera, but its targets are completely up to the public.
You can go vote about what you think will be the most interesting thing for JunoCam
to take pictures of, and NASA will point it at whatever gets the most votes.
If you want to be a part of that discussion, there’s a link to the website in the description!
The first JunoCam pictures of Jupiter are going to be released on Monday, right after
Juno enters the Jupiter system.
So keep an eye out for those.
While they were building all of this, the mission scientists had a lot to figure out:
Juno can’t point all of these instruments at Jupiter at the same time, so it’ll be
cartwheeling through space twice every minute -- that way, every instrument gets its turn
facing the planet for a few seconds at a time.
So they have to be pretty well coordinated to get the high-quality data that NASA expects.
And the cameras have to work in pretty low light, too.
Jupiter only gets about 4% of the sunlight that Earth does, which led to yet another
challenge.
Every other mission to the outer solar system has brought along its own power, in the form
of a small on-board nuclear power plant.
But not Juno.
It’s going to be the most distant solar-powered ship we’ve ever sent out into space.
And even with its huge solar panels, Juno still has only about 530 Watts of power to
do all this incredible science with.
That’s less power than your microwave uses -- and all it’s doing is heating up your
hot pocket, not teaching us about the origins of the solar system!
But sadly, NASA’s only allowing Juno to operate for about a year and a half before
they steer it down into Jupiter, where it’ll burn up in the atmosphere.
That might seem like a short timespan and a strange end for a billion-dollar mission,
but there’s a good reason why:
It’s possible that Jupiter’s moon Europa has life in its subsurface oceans, and NASA
doesn’t want to take any chance of Juno crashing into Europa and contaminating it
with microbes from Earth.
And launching Juno out of the Jupiter system would’ve meant bringing along way more fuel.
So Juno is just going to aim for the king of the planets and dive in.
The probe isn’t designed to work in Jupiter’s clouds, so it won’t be able to return any
data while it’s down there.
But we’re sacrificing Juno so that if there is alien life on Europa, it can continue uninterrupted.
Which seems like a pretty noble way to go out.
We’ll be tracking the Juno mission’s findings here on SciShow Space, so keep checking back
if you want to learn more about Jupiter with us.
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