Juno Images … a new look at Jupiter

Here is just one sample of the discoveries NASA’s Juno Mission is making as it orbits Jupiter.

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This is how our textbooks show Jupiter. Well, the brilliant aurora around the north pole is an “upgrade” based on newer observations and clever image enhancement to make them look brighter (they are real, just not that bright). However, this is the Jupiter we are familiar with … all bright face  ….  wonderful multicolored stripes. We have always seen it fully lighted like this, because it orbits way out there away from the Sun. The Earth is in a much tighter orbit around the Sun. From here, or from our Hubble Telescope orbiting Earth, we might as well be seeing it from the perspective of the Sun. Those stripes are equatorial bands of big (really big) and very persistent storms. Many Earths would fit inside the biggest, called “the great red spot.”

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Here is a recent picture of Jupiter just taken by the Juno spacecraft. This is a brand new perspective! We are looking directly downward onto the planet’s south pole. The Juno spacecraft is in a polar orbit around Jupiter that is highly elliptical. It moves slowly at great altitude and then whips down much closer to the surface at the opposite side and climbs back up to its peak altitude.  That way, it spends as little time as possible close to Jupiter and inside the radiation belts that would be lethal to its electronics. However, it will observe the whole planet as geography slowly rotates beneath the orbit plane. Also it can get some great closeups.

From this perspective, only the half of Jupiter is facing the Sun is lighted. The Sun would be far away, straight up in the picture. The familiar bright colored storm bands are barely discernable out at the edges (which would be Jupiter’s equator). Near the south pole, the storms are also huge, but appear as whirling eddies in the atmosphere moving chaotically. The dominant color is blue/grey, not the orange and white stripes we normally observed.

There will be lots to learn from Juno.

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Juno in Orbit Around Jupiter

Guys,

The enormous NASA spacecraft, JUNO, arrived at Jupiter over the 4th of July weekend. It successfully zipped in close to Jupiter, firing its braking rocket motor for half an hour to reduce speed sufficiently to allow Jupiter’s gravity to capture the spacecraft and pull it into orbit around the planet. Now it is in a very elliptical orbit which will bring it back to Jupiter in about two months. Then another braking maneuver will slow it down even more and it will finally settle into its mission pattern of two week long elliptical orbits. It all sounds complicated, but there is a good reason.

Typically, an ideal orbit for planetary observation would be a simple circular orbit just like the ones used by weather satellites circling Earth. Those fly 530 miles high over the poles and, beneath them, the Earth rotates just enough so that the next pass will be over a new swath of the planet. That 530 mile high orbit gives the spacecraft just the right speed so that after 12 hours the satellite will have observed the whole planet. Barnes Engineering developed and built the Earth sensors for all of these workhorse satellites and a few classified payloads for military versions.

imagesJupiter is quite different from Earth so the simple circular orbits won’t work. First it is enormous. Orbits around it are measured in terms of weeks not hours. Here is a clever graphic representation of just how big Jupiter is compared with Earth. Yes, those are little Earths spilling out.
Second, Jupiter’s interior is a massive magnetic field generator because it is compose of highly conductive hydrogen. The gravity of Jupiter is so strong it compresses hydrogen gas into a liquid and, finally, at the very center, solid metallic hydrogen.  It may be a “gas planet” but it does have a heart. In the same way that Earth’s churning conductive iron core creates a magnetic field around our planet, Jupiter’s hot, turbulent core surrounds it with a vastly stronger and more complex magnetic field. This field traps radiation from the Sun in intense belts very much like the Van Allen Radiation Belts around the Earth … but a thousand times inside.enstronger. So lethal to spacecraft components are Jupiter’s radiation belts that Juno could not survive in any close-in circular orbit that allowed that radiation to beat on it continuously. Even with its thick titanium “vault” engineered to shield critical instruments, it must do something to limit its exposure.
orbits-1050NASA’s clever solution was to survey the planet in a series of swooping passes that race through the belts and quickly back out again. Highly elliptical orbits are perfect for this. When close to Jupiter, Juno will be going extremely fast.  Then it loops up higher than the orbits of Jupiter’s moons and well outside the radiation belts. While inside the belts, the spacecraft will be near enough to Jupiter to make close-up observations, take pictures, and do serious science. When on the high, slow part of the elliptical orbit it is well out of harms way and can “cool down.” Each mission orbit will take two weeks. By the time it swoops in again, Jupiter will have rotated just enough for the next pass to observe a new part of the planet …. the same approach as Earth’s weather satellites.
This diagram shows the “Jovian System” {Jupiter and its moons} off to the right.  These are the moons that Galileo discovered with his first telescopic observation of the heavens. You can see the trajectory on which Juno arrived at Jupiter coming in from the upper left corner. The two big ellipses are the initial orbits that the spacecraft will be in for the next four months. The group of smaller ellipses are the two week mission orbits that will systematically map Jupiter. After about twenty passes, Juno will be de-orbited into Jupiter (if it has indeed survived long enough to get that command to self-terminate).
In addition to heavy duty science, we will also be treated to fresh images of Jupiter from front row seats and fly-by images of several of its moons. NASA is turing Juno’s instruments on today. Exciting time ahead.
Here is a NASA website with lots of good graphics, animations and even videos of people celebrating.
Love Ya!
Paw, Dad, Robbie

Juno!

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Finally, a new post from Paw (via his tech crew)… time for some awesome space science! 

Juno has arrived at Jupiter and will start sending us images soon. WOW!

‘Welcome to Jupiter!’ NASA’s Juno space probe arrives at giant planet

Juno probe enters Jupiter’s orbit following ‘amazing’ Nasa mission – as it happened

Juno probe enters into orbit around Jupiter – BBC News

More news for juno arrives at jupiter

http://www.cnn.com/2016/07/04/world/juno-jupiter-nasa/

It’s like having the cloak-of-invisibility and a diamond sword…

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Thank you for your article on the Zumwalt.

We all remember that Piper was doing a science project last summer on Stealth Technology.  The “Zumwalt” was designed from the very beginning to have a very low “radar signature.”  A radar signature is the distinctive signal bounced back to an enemy radar operator.  It is what he would observe when the target was within range of his radar. Continue reading “It’s like having the cloak-of-invisibility and a diamond sword…”

Pluto!

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The fly-by mission to Pluto is months ago, but it has taken until now for the first really high resolution pictures to be painstakingly downloaded to Earth. The “New Horizons” spacecraft is very far from us now as it leaves the solar system and it must do it’s best with limited power, a very small antenna and very old technology to get those images all the way back to us. Continue reading “Pluto!”