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Juno Arrival This Year!


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On 3/8/2016 at 10:42 PM, Frida Space said:

The JOI (Jupiter Orbital Insertion) Phase begins four days ahead of the actual JOI burn. If things haven't change since I last checked, TIG (Time of Ignition) is scheduled for just before 2:30 am GMT on July 5th, so early July 4th in the US. The burn will be performed at perijove, some 4500 km above the 1-bar level (referred to as the "surface" of the planet, although obviously it's not solid). The JOI burn will last slightly over 30 minutes and result in a Delta-V of about 480 m/s. At JOI, there will be a 48.3-minute delay (one-way) in the communications due to Juno's distance from Earth.

[...]

Regarding my previous post on this thread (quoted here above), there have been several changes to the flight plan following updated models on Jupiter's magnetosphere

- Instead of achieving a 107-day-period preliminary orbit, Juno will execute a slightly more fuel-intensive (542 vs 480 m/s) insertion burn (JOI) to achieve a capture orbit of 53.5 days. The s/c will complete two of these capture orbits, going for a test run of its scientific campaign on the second orbit

- After two capture orbits, a period reduction manoeuvre will lower Juno onto its scientific orbits. The original 10.9-day-period orbits are now 14 days long, allowing the scientists to have more time to react to unexpected discoveries and better plan the observations

- Longer orbits mean longer mission (20 months instead of 15), but we will have a global picture of Jupiter (however basic) as soon as orbit number 8

The fact that they want to get a global picture sooner, together with a recent talk given by Fran Bagenal ("we don't know how long the s/c will survive, if we only get 10 orbits we will learn a lot about Jupiter"), suggests to me that the scientists fear the radiation dose felt by Juno will be worse than predicted. Of course it's probably only a "hey, don't expect us to survive ten years" call, but still, I find it pretty remarkable that they've chosen to make such important changes to the flight plan so late on in the mission.

Godspeed Juno :)

Edited by Frida Space
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On 6/5/2016 at 9:40 AM, Veeltch said:

Can we expect some nice pictures to be taken by the onboard camera soon-ish?

The Junocam isn't a proper instrument - it will be able to take images only when the other instruments aren't collecting data (they have the priority), plus it's not fully shielded against radiation, so it's expected it will fail after some seven-eight orbits (but let's hope it stays on a bit more than that). Furthermore, it's more of an educative/outreach effort than a proper scientific camera. From my understanding, instruments will be turned on around the second capture orbit, so some 52 days after the insertion burn, but I'm not sure if that applies to Junocam too. Let's hope we get some bonus early picture :)

Edited by Frida Space
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On ‎3‎/‎8‎/‎2016 at 8:42 AM, UnusualAttitude said:

(American epic movie trailer voice) Coming this summer to a gas giant near you...

For that, we can thank Bill Nye. Be careful what you wish for! (lol)  I found his grade-school targeted videos about the Juno mission, while checking out the videos linked by @SuperFastJellyfish  :wink: 

Why with Nye (Ep. 1): Bill Nye and Juno the Solar-Powered Spacecraft
Why with Nye (Ep. 2): Throwback to Juno's 2013 Earth Flyby
Why with Nye (Ep. 3): 'Does Jupiter Have a Core?'

Fun & funny stuff :) 

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On 6/1/2016 at 9:15 AM, Spaceception said:

Really? I didn't know Jupiter's SOI was that big. That's pretty cool.

If you check "small moons" orbits in Space Engine, you'll see that Jupiter has a moon cloud that is several times larger than the Moon in our sky. It's *really* big.

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On 1.6.2016 at 4:15 PM, Spaceception said:

Really? I didn't know Jupiter's SOI was that big. That's pretty cool.

Jupiter is one of those things that you can apply what I call "the rule of superlatives" to. In other words, whatever characteristics you commonly attribute to Jupiter, it probably exceeds them. :P That is because we lump it into the category of "planet" together with stuff like Earth and Mercury. So the average person will instinctively think that Jupiter can't possibly be all that much bigger than us, right?

Wrong! Jupiter is 10% the size of the Sun, and has 2.5 times the mass of all other confirmed planets in the solar system combined... in fact, as much as 50% more than all other non-Sun mass in the solar system combined, according to current models. It is almost 29 times the size of Mercury (the smallest planet), so there is more than twice as much of a size difference between Jupiter and Mercury than there is between Earth and Ceres (the smallest dwarf planet). It orbits a common barycenter with the Sun, instead of just orbiting the Sun. Jupiter is the third brightest object in the night sky, and the light it reflects can cast shadows. Due to its huge influence on everything that moves around the Sun - even commsats in geostationary orbit need to compensate their orbits getting perturbed - Jupiter's existence is thought to be so critical to the formation of our solar system that without it, Earth would not have developed life.

So yeah. Absurdly humongous and massive. Respect the Jupiter, or it will... perturb you! :P

Edited by Streetwind
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On 1.6.2016 at 4:15 PM, Spaceception said:

Really? I didn't know Jupiter's SOI was that big. That's pretty cool.

Same as Jool SOI, with an Hohman you end up with two months before you reach the moons. 
You end up doing the final adjustment burns inside it, going to Duna you do it far outside 

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I'm here a bit late, but, YAY JUNO! As for why RTG's aren't used, there are the reasons pointed out above. There is another reason, though. America now only has enough Plutonium to make 3 more of them. The reactors that make plutonium are slowly being turned back on, though.

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  • 3 weeks later...

One more week guys! One week!

Does anyone knows how much time for the first data arrival? I know that each capture orbit will take 53/54 days and the 'science' orbits will be 14 days long. So more 100 days to start making science or they will do something already on the capture orbits?

 

EDIT: Well, looks like we already have something from JunoCam from last Tuesday:

PIA20701_fig1.jpg

Edited by VaPaL
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On 08/03/2016 at 10:34 PM, Spaceception said:

The solar panels are a result of Budget cuts (I'm pretty sure, I'm not sure why you'd want solar panels so far from the sun either)

Solar panels are used due to a combination of reasons:

- Plutonium fit for space is becoming increasingly rare, due to the limitations on (the production of) nuclear weapons. The supply is almost dry and attempts to start production back up for RTG fuel are not yielding much material (yet).

- Solar panels are becoming more and more efficient, making them a viable option for missions far from the sun.

You are going to want to use your fuel for those missions that cannot be done without it. It seems to be using solar panels also imposes less restrictions on the mission, as people get antsy when you are flying nuclear fuel. Having hypergolics rain on your house is no fun either, though it is to be preferred over plutonium.

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On June 28, 2016 at 9:17 AM, Veeltch said:

I hope they make the most of JunoCam. It would be nice to get some fresh pictures of Europa and Io.

It's camera isn't really that good unless it gets very close.

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8 minutes ago, Bill Phil said:

It's camera isn't really that good unless it gets very close.

I know :C would send NASA my 8MPix phone if I knew they were putting a camera on it.

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As I was sitting with friends and my brothers waiting for the cities fireworks to begin I happened to sight Jupiter in the western sky. My thoughts were of what it would look like seeing the planet Jupiter from the perspective of Juno at the moment. It was still over 24 hours away from orbital insertion at the time but I could image the gas gaint dominating the field of view as the spacecraft drew closer. It's going to be a treat to see new close up imagery of Jupiter from Juno in the coming weeks,

Edited by Exploro
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7 minutes ago, Exploro said:

As I was sitting with friends and my brothers waiting for the cities fireworks to begin I happened to sight Jupiter in the western sky. My thoughts were of what it would look like seeing the planet Jupiter from the perspective of Juno at the moment. It was still over 24 hours away from orbital insertion at the time but I could image the gas gaint dominating the field of view as the spacecraft drew closer. It's going to be a treat to see new close up imagery of Jupiter from Juno in the coming weeks,

This is a very interesting app for Windows, which can do exactly that: https://eyes.nasa.gov/

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On 07/06/2016 at 3:28 AM, cubinator said:

If you check "small moons" orbits in Space Engine, you'll see that Jupiter has a moon cloud that is several times larger than the Moon in our sky. It's *really* big.

And yet it's the smallest "Sphere of influence" of the gas giants, barely half the diameter of Neptune's. Neptune's vastly greater distance from the Sun more than makes up for its much lower mass in the 'tug of war' between star and planet.

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