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Hi, I'm Matt and this is NASA Now.
The role of a NASA scientist is to ask questions
and search for answers.
That's exactly what the Jupiter-based mission Juno is
all about.
Today we're going to find out what scientist hope to learn
about this enormous planet that is sometimes referred
to as the gatekeeper to the solar system.
That's ahead, first here's what's happening at NASA Now.
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NASA scientists discovered new evidence that Earth has been hit
by many asteroids similar or larger than the one thought
to have killed the dinosaurs some 65 million years ago.
By combining sophisticated computer models
with physical evidence from the past, researchers are able
to show that there may have been as many as 70 giant asteroids
that impacted our planet 1.8 - 3.8 billion years ago.
Further research shows at the same time
that approximately four similarly sized objects hit the
moon as well.
These findings support the theory that Jupiter, Saturn,
Uranus, and Neptune formed
in different orbits nearly 4.5 billion years ago.
It was the movement to their current orbit 4 billion years
ago that triggered a solar system wide bombardment
of comets and asteroids called the "Late Heavy Bombardment".
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The gas giant known as Jupiter may hold the answers
to the very beginning of the solar system.
To gain more insight about the composition, evolution
and atmosphere of Jupiter, NASA developed the Juno mission.
Tracy Drain, a Juno Systems Engineer
from the Jet Propulsion Laboratory in Pasadena,
California, joins us with information
on the Juno spacecraft and what scientists hope to learn
when it reaches Jupiter in the summer of 2016.
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Jupiter is important for a lot of reasons.
It is the largest planet in the solar system
and scientists believe that it was probably the first planet
to form in our solar system and that it still maintains most
of the material that it had way back during the formation.
So learning more about Jupiter will help us understand more
about the solar system itself.
You can think of Jupiter as sort of a time capsule
for the whole solar system.
This is the Juno spacecraft
and the biggest features are the three large solar arrays.
The fact that the solar arrays are so large much larger
than the body of the spacecraft because Juno is
so far away from the sun.
It needs those to be able to gather enough light
to generate enough power for the spacecraft.
Out here on the edge this boom holds one
of our instruments called the mag.
It's the magnetometer.
It has two flux gate magnetometers
and some little star cameras
to help it understand exactly where it is.
It has to be this far away
because the magnetic field generated
by the spacecraft might interfere
with the measurements it's trying to make
of the magnetic field of Jupiter.
In the middle, this shinny silver dome that looks like one
of those old fashioned popcorn poppers,
that's actually our high gain antenna that we use
when we're really far away from the earth to send data back
to Earth and also for the spacecraft
to get commands from the ground.
And you can see tucked up under this high gain antenna is what
we call the vault.
This is a box made of titanium
where our sensitive electronics are stored inside in order
to protect them from the intense radiation
around the planet Jupiter.
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These little pedestals that have three little items poking
out of them, those are the thrusters that we use
to control the spacecraft attitude.
We use those to send out little puffs of gas in order
to adjust the way the spacecraft is pointing
and Juno actually is a rotating spacecraft.
It spins not very fast and we do that because
that helps maintain stability of the spacecraft.
You have to fire your thrusters a lot less often
to maintain the attitude that you want
because of the whole gyroscopic effect.
Here on the backside of the spacecraft,
this is the waves instrument and I'll also point
out two little antennas very close on the side
of the high gain antenna.
One is the medium gain antenna,
which has a wider beam width than the high gain.
You can think of the high gain as like a giant flashlight,
a really focused powerful flashlight and if you're shining
that on the wall you'd see a fairly small spot so you have
to be pointed really carefully at the Earth or the spot
on the wall in order to communicate but if
for some reason you happen
to be off pointed a little you won't be able to communicate
with the high gain antenna.
The medium gain antenna has a wider beam width.
You can think of it as more of a flood light and then right next
to it is a low gain antenna and you can think
that as a light bulb where it's sending out light almost
in a big hemisphere in one direction or sending
out radio signal which travels at the speed of light.
We use that one when we might not be sure what the attitude
of the spacecraft is so you can still talk to it and there's one
on the back too, sending out that little hemisphere
of radio signal on the other side.
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To find out more about the Juno mission
and to track the progress of the spacecraft,
check out the NASA Explorer Schools' Virtual Campus.
Teachers, our expert has provided us
with some great links
to educational resources you can use to keep your students
in the know about Juno.
For more information visit the NASA Explorer Schools'
Virtual Campus.
Well that's it for NASA Now,
be sure to visit our Facebook page and leave a comment.
We'll see you next time on NASA Now.
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NASA Now comes to you from the Virtual Campus
at NASA Explorer Schools.