Humans to attempt insertion of Jupiter
July 4, 2016 5:25 AM   Subscribe

Mission Juno Tonight, Earth species Homo sapiens sapiens, with ongoing support from photosynthesizing relatives in the Plant kingdom, will attempt the delicate task of inserting a large machine into polar orbit around the highly radioactive gas giant Jupiter. After using a slingshot maneuver around Earth and Jupiter's tremendous gravitational pull to become "one of the fastest human-made objects ever built," it is hoped Juno will collect data for 20 months, shedding light on the composition of the planet and what it can tell us about the origin of the Sol system 4.6 billion years ago.

It is expected that planetary scientist Emily Lakdawalla, among many others, will spend 2016 July 4-5 providing members of H. sapiens sapiens and other internet-dependent species with fun and interesting updates throughout the procedure.
posted by mediareport (194 comments total) 57 users marked this as a favorite
 
What I want to know is: Is Niel DeGrasse Tyson going to have a hard time going to sleep tonight night like a kid on Christmas Eve?
posted by Nanukthedog at 5:42 AM on July 4, 2016 [6 favorites]


We should know if the orbital insertation (phrasing) was successful around midnight EST.
posted by Brandon Blatcher at 6:01 AM on July 4, 2016 [2 favorites]


Humanity: exploring strange new worlds to find out if we can insert ourselves into them.
posted by frogstar42 at 6:08 AM on July 4, 2016 [13 favorites]


Yeah, to be very specific, the 35-minute engine firing (from instructions turning on the auto-pilot that were sent on June 30) begins at 11:18pm ET, slowing Juno down enough to be captured into a polar orbit.

We hope.

So exciting!
posted by mediareport at 6:29 AM on July 4, 2016


I was ready to go yawn, New Horizons had to conduct its entire science program in a couple of hours, but then I read this (from the fastest link):

After reaching a max speed of 165,000 mph — fast enough to fly around Earth in nine minutes — Juno will slam on the breaks[sic] by firing its engines. This is where things get tricky.

The Juno spacecraft weighs 3,500 pounds and will be barreling through space at 215 times the speed of sound. To slow down, the engines will fire for 35 minutes straight, burning through 17,600 pounds of fuel.


So at the moment Juno weighs about 20,000 pounds most of which is fuel, all of which it is going to burn tonight in one big maneuver, in an environment as radioactive as the basements of Chernobyl and Fukushima. Okay, NASA, you have got my attention. I guess Curiosity's sky crane wasn't crazy enough for you, huh?
posted by Bringer Tom at 6:37 AM on July 4, 2016 [32 favorites]


The illustrated orbit trajectory looks like something you'd put on your dorm room wall.
posted by mrjohnmuller at 6:40 AM on July 4, 2016 [13 favorites]


will be barreling through space at 215 times the speed of sound.

The speed of sound... in space?
posted by indubitable at 6:45 AM on July 4, 2016 [5 favorites]


After reaching a max speed of 165,000 mph

Pfft. I've done that. In that old Nova that Ted fixed up.

*feels inadequate*
posted by petebest at 6:49 AM on July 4, 2016 [2 favorites]


This is so cool. I remember watching those first amazing Jupiter images come in from Voyager 1 in '79 and missions like this make me feel like I'm that geeky teenager again.
posted by octothorpe at 6:51 AM on July 4, 2016 [2 favorites]


The illustrated orbit trajectory looks like something you'd put on your dorm room wall.

Is that a standard orbit?
posted by thelonius at 6:54 AM on July 4, 2016


Radiation (rapid acceleration of charged particles by a magnetic field) ≠ radioactive (energy released by the decay of atomic nuclei).
posted by Spathe Cadet at 6:55 AM on July 4, 2016 [10 favorites]


What I want to know is: Is Niel DeGrasse Tyson going to have a hard time going to sleep tonight night like a kid on Christmas Eve?

If so, I look forward to his tweets mangling other fields of study.
posted by ROU_Xenophobe at 6:56 AM on July 4, 2016 [15 favorites]


Yeah, Mr. White. Yeah, science.
posted by roomthreeseventeen at 6:57 AM on July 4, 2016 [4 favorites]


If successful this would only be the second spacecraft to orbit Jupiter. The first was Galileo from 1995-2003. Every other craft has simply been a flyby.
posted by Brandon Blatcher at 6:57 AM on July 4, 2016 [6 favorites]


Is that a standard orbit?

No, it's specifically designed so that Juno doesn't spend much time in the dangerous radiation areas. It's a two week orbit as it dives in to about 3,000 miles above the clouds, then zips out.

Fun fact: since Juno is solar powered, it will never go behind Jupiter, except for the orbit insertation burn. The batteries were sized to survive that one pass in the darkness and supposedly they're cutting it close.
posted by Brandon Blatcher at 7:02 AM on July 4, 2016 [9 favorites]


All I want is a room of happy scientists and engineers jumping up and down like it's Christmas morning. Come on, Juno, you can do it!
posted by longdaysjourney at 7:11 AM on July 4, 2016 [12 favorites]


Radiation (rapid acceleration of charged particles by a magnetic field) ≠ radioactive (energy released by the decay of atomic nuclei).

Unless it's gamma radiation, when it does. Respect the photon.

All the fun is happening in the very early morning for me, which is a bugger, but I think I'll try an early night. I like Juno because I took part in a PRsperiment on its Earth flyby,. NASA asked radio hams to send a Morse message to it on 28 MHz, right in the middle of its radio science window. saying HI JUNO - I forget whether there was much real engineering reason for it, but it felt good anyway.
posted by Devonian at 7:21 AM on July 4, 2016 [9 favorites]


We're gonna measure the shit out of the magnetic and gravitational fields to figure out what's at the center of the second largest body in the solar system. God I love space.
posted by Skorgu at 7:25 AM on July 4, 2016 [7 favorites]




I guess Curiosity's sky crane wasn't crazy enough for you, huh?

Though I wouldn't review it quite as highly as Curiosity's rousing Dare Mighty Things, Juno also has a dramatic mission trailer - - Jupiter: Into the Unknown.
posted by fairmettle at 7:29 AM on July 4, 2016 [1 favorite]


Radiation (rapid acceleration of charged particles by a magnetic field) ≠ radioactive (energy released by the decay of atomic nuclei).

Unless it's gamma radiation, when it does. Respect the photon.


I think the point was that calling Jupiter "highly radioactive" is inaccurate, because the high levels of radiation have nothing to do with its nuclei (as the linked article explains well) .
posted by kleinsteradikaleminderheit at 7:53 AM on July 4, 2016 [5 favorites]


The first was Galileo from 1995-2003. Every other craft has simply been a flyby.

A few days ago Lakdwalla linked this great animation from New Scientist of all the paths of spacecrafts we've sent near Jupiter since 1973. The path of Galileo starts at 0:30 and is a thing of beauty.

And thanks, Spathe Cadet, for the correction about radioactivity vs. radiation. I love the info in that link about Jupiter being such a radiation hot zone in part because of the additional plumes of particles coming out of the volcanoes on Io.
posted by mediareport at 7:55 AM on July 4, 2016 [11 favorites]


This is very exciting, and I will be keeping an eye on this this evening.

Meanwhile, in other parts of the solar system: New Horizons receives mission extension, Dawn to remain at Ceres.
posted by nubs at 8:04 AM on July 4, 2016 [3 favorites]


The path of Galileo starts at 0:30 and is a thing of beauty.

That is awesome, thanks for linking this. But does the Galieleo Probe not count as a spacecraft? I was looking forward to seeing a tiny little "orbit" that smacks right into the fucker...
posted by kleinsteradikaleminderheit at 8:07 AM on July 4, 2016


I know it's confusing - as is the old ionising/non ionising radiation distinction - and I wouldn't call Jupiter 'radioactive' myself (although a lot of it is, of course, being nicely exothermic as a result), but the normal term for the energetic areas around Jupiter is 'radiation belts', with exposure measured in the same way as for any radioactive area. And particles and waves are convenient descriptions - it's all fields in the end.

It's certainly true that most of the radiation in Jupiter space is not caused nuclear decay, which is what 'radioactive' normally describes. It's not true that this makes it all different from some of the products of nuclear decay. - although, to be honest, I don't know whether there's any energetic overlap between classic EM processes and gamma decay. There are no limits in Maxwell; I don't know QED well enough to say.
posted by Devonian at 8:26 AM on July 4, 2016 [1 favorite]


thelonius: "The illustrated orbit trajectory looks like something you'd put on your dorm room wall.

Is that a standard orbit?
"

Werry sorry, Keptin.
posted by Splunge at 8:27 AM on July 4, 2016 [10 favorites]


Oh yeah, I don't think there's a standard orbit for a spacecraft. It depends on the mission objectives. Maybe there's standard polar orbits for spacecraft around a specific planet? Or a standard orbit for a spacecraft mapping the magnetosphere of a specific planet?

Yes, this is pedantic, but also fascinating!

Now, listen to the sound of NASA’s Juno spacecraft crossing into Jupiter’s magnetic field
posted by Brandon Blatcher at 8:35 AM on July 4, 2016 [5 favorites]


I think the point was that calling Jupiter "highly radioactive" is inaccurate, because the high levels of radiation have nothing to do with its nuclei (as the linked article explains well) .

I imagine Jupiter has plenty of alpha and beta "rays" at energies close to the speed of light. But the point is that radiation is radiation, regardless of the source. given the energies involved describing the orbital environment as "radioactive" is entirely accurate. anything up there is going to be absorbing a lot of energy from highly accelerated charged particles...
posted by ennui.bz at 8:39 AM on July 4, 2016


Oh yeah, I don't think there's a standard orbit for a spacecraft. It depends on the mission objectives. Maybe there's standard polar orbits for spacecraft around a specific planet? Or a standard orbit for a spacecraft mapping the magnetosphere of a specific planet?

The orbit that Juno is on is a highly elliptical orbit designed to take it extremely close to Jupiter while utilizing the gap in the magnetic field lines of Jupiter's magnetosphere (the polar cusp) to minimize the amount of charged particles the probe will have to plow through. This in turn will limit the damage to the probe's electronics and let it last longer.
posted by Talez at 8:43 AM on July 4, 2016 [1 favorite]


Just out of interest, similar elliptical orbits called Molniya have been used back here on Earth for comsats as, in some cases, there are useful advantages over GEO, although those are less compelling these days. Here, the useful bit of the orbit is that furthest away from the planet.
posted by Devonian at 9:06 AM on July 4, 2016 [1 favorite]


I didn't mean to start a derail to adjudicate the meaning of "radioactive." Apologies to mediareport and photons. I swear I respect you both.
posted by Spathe Cadet at 9:33 AM on July 4, 2016


Sometimes it's cool to live in the future.

Jetpacks please
posted by the uncomplicated soups of my childhood at 9:43 AM on July 4, 2016 [3 favorites]


Quite the first, it was always Jupiter inserting itself into beautiful Greek people before this, right?
posted by Slackermagee at 9:58 AM on July 4, 2016 [14 favorites]


The amount of radioactive isotopes on Jupiter is unknown AFAIK. Jupiter is kept nice and hot (-145C on the surface) mainly by the Kelvin-Helmholtz mechanism, which is pretty awesome - if you cooled Jupiter down, it would shrink and heat right back up. If you added some mass, it would shrink a little and also heat up. If you added enough mass, it would ignite.
posted by kleinsteradikaleminderheit at 9:58 AM on July 4, 2016 [6 favorites]


If you added enough mass, it would ignite.

Modified entry for "Earth" in the Hitchhiker's Guide to the Galaxy: "Mostly harmless, except for the time they set fire to Jupiter."
posted by storybored at 10:04 AM on July 4, 2016 [10 favorites]


The speed of sound... in space?

Close on a million times the speed of smell (often colloquially but inaccurately known as one megafart).
posted by Segundus at 10:06 AM on July 4, 2016 [3 favorites]


"Mostly harmless, except for the time they set fire to Jupiter."

Heh, I think it would take dozens of Jupiter masses to make the core ignite... But until then it would be smaller than it is now! (after ignition I guess the heat would increase the size)
posted by kleinsteradikaleminderheit at 10:10 AM on July 4, 2016


The amount of radioactive isotopes on Jupiter is unknown AFAIK.

But, in principle, it should have less heavy elements, in proportion to it's total mass, than the inner rocky planets.

Still, I imagine a human in orbit around Jupiter would get cooked by the beta particles, unless they were wearing a suit of fairly thick metal armor... which would create its own potentially hazardous RF effects. no one wants to be stuck in a high energy electromagnetic wave guide (see microwave ovens)...
posted by ennui.bz at 10:12 AM on July 4, 2016


kleinsteradikaleminderheit: ""Mostly harmless, except for the time they set fire to Jupiter."

Heh, I think it would take dozens of Jupiter masses to make the core ignite... But until then it would be smaller than it is now! (after ignition I guess the heat would increase the size)
"

Or maybe a million or so Monoliths.

posted by Splunge at 10:14 AM on July 4, 2016 [6 favorites]


My kids are so excited about this that Juno has replaced Cassini as their favorite satellite. So excited they don't want to watch fireworks tonight because they've been telling me for months that "Fourth of July is when Juno gets to Jupiter!"

(We go to the planetarium on average twice a week and the little one pretty much learned to read from the captions on NASA photos that they project between star shows in the dome, with the result that he can read words like "Gallilean" and "Jupiter" and "orbiter" but not "could" or "said." Enjoy my child, unsuspecting kindergarten teacher!)
posted by Eyebrows McGee at 10:18 AM on July 4, 2016 [55 favorites]


no one wants to be stuck in a high energy electromagnetic wave guide

YOU DON'TKNOW ME.
posted by Brandon Blatcher at 10:22 AM on July 4, 2016 [14 favorites]




Looks like the Jovians have turned on the light show for Juno's polar orbit.
posted by autopilot at 10:42 AM on July 4, 2016 [5 favorites]


I stand corrected on Jupiter's heat; I didn't know that gravitational contraction was so significant at that sort of size. There's also a third mechanism proposed, differentiation of H and He, that could be a significant contributor, as discussed in this short paper, which also demonstrates quite nicely that none of the numbers add up yet. Which is why we have things like Juno, of course...
posted by Devonian at 10:48 AM on July 4, 2016 [3 favorites]


Now, listen to the sound of NASA’s Juno spacecraft crossing into Jupiter’s magnetic field

Juno is an interplanetary dialup modem! That explains why the latency is so high and the connection from the Deep Space Network is so bad!

Is there some interplanetary version of FiOS that we can deploy?
posted by Talez at 10:55 AM on July 4, 2016 [2 favorites]


I can never watch these things live, too tense. It takes so much effort to get them to these places, and there's so much science lost if they fail.
posted by tavella at 11:45 AM on July 4, 2016


Is there some interplanetary version of FiOS that we can deploy?
posted by Talez at 18:55 on July 4 [+] [!]


Thanks, Obama.
posted by Devonian at 11:46 AM on July 4, 2016 [4 favorites]


Also, last this the last image Juno sent before shutting down its instruments for the insertion.

hm...so...seems like it's coming in from the side...
I've been scouring all the juno websites and can't seem to figure out when the first images will be sent back...science starts on the next orbit (50+ days) but surely there will be some calibration images before then, no?
posted by sexyrobot at 11:53 AM on July 4, 2016


sexirobot, Juno is in an elliptical orbit around the Sun that stretches from Earth's orbit out to Jupiter's. It gets to the outermost point, where it touches Jupiter's orbit, at the same time as Jupiter gets to the corresponding point on its orbit.

However, Juno is going slower than Jupiter (which is why it's in an orbit that, if Jupiter didn't capture it, would have it falling back down towards the Sun). So, Jupiter is catching up with Juno, which means that as Juno approaches Jupiter it is actually coming in from ahead of Jupiter from Jupiter's perspective as it goes around the Sun.
posted by Major Clanger at 12:20 PM on July 4, 2016 [3 favorites]


I really hope this works.
posted by humanfont at 12:41 PM on July 4, 2016 [2 favorites]




A full list of the events and briefings and links to lifestreams for all of them

Apologies if this was linked earlier... I didn't see it.
posted by hippybear at 1:05 PM on July 4, 2016 [3 favorites]


hippybear, I should have made it more prominent but the "Lakdwalla" link in the original post is to her roundup How to watch Juno's orbit insertion, which includes another really neat 360-degree simulation of the approach, this one as it happens in real time. It's gotten noticeably closer since this morning.
posted by mediareport at 1:24 PM on July 4, 2016 [1 favorite]


Oh great Roman and other gods may this go well. As I've mentioned before, it is "my" mission in a special way - I participated in the NASASocial surrounding its launch. (I recently posted a link to a pic of me and other tweeps at the launchpad on Aug. 4, 2011.)
posted by NorthernLite at 1:30 PM on July 4, 2016 [3 favorites]


Pathfinder's landing on Mars (1997) and Deep Impact's impactor's ...impact with comet Tempel 1 (2005) also happened to fall on the 4th of July. Nice planning, NASA! :)
posted by bigendian at 1:31 PM on July 4, 2016


Omg, that real time simulation is dream come true!
posted by Brandon Blatcher at 1:54 PM on July 4, 2016


Why can the scientists not keep Juno's camera operating during the insertion phase? It seems like something you would want to study in case of failure and/or release to the internets for goodwill and future funding.
posted by efalk at 1:57 PM on July 4, 2016


Battery power probably. The goal is to ensure insertation, everything else takes a back seat. EVERYTHING.

It would be nice to have video, but why push it.
posted by Brandon Blatcher at 2:00 PM on July 4, 2016 [1 favorite]


Might be going through high radiation belts too. Definitely want things shut down then!
posted by Brandon Blatcher at 2:02 PM on July 4, 2016


This is an amazing triumph of technology and human curiosity, but why did they need to add an extra syllable to "insertion", exactly?
posted by gingerest at 2:55 PM on July 4, 2016 [1 favorite]


Heh, I think it would take dozens of Jupiter masses to make the core ignite.

The smallest dwarf brown is around 14x Juptier's mass, so a single dozen might be enough.
posted by bonehead at 3:01 PM on July 4, 2016


why did they need to add an extra syllable to "insertion", exactly?

I see weird non-words used in place of regular words so much online these days... But I'd assume that NASA uses vocabulary with precision, so they must have a reason for that particular word.

Although a quick google shows that the word doesn't exist except for in one Yahoo Answers question about coitus.
posted by hippybear at 3:04 PM on July 4, 2016 [2 favorites]


Why can the scientists not keep Juno's camera operating during the insertion phase?

There has been a bit of a change in the basic philosophy of planetary probe design since Voyager, Galileo, and Cassini. The old model is to make the probe a highly stable platform around which the science instruments and propulsion rotate to get to where they need to be. The problem is that this turned out to be complicated, power-hungry, and failure prone.

The new model is to make the hardware as simple as possible while getting the job done, which generally means spin stabilization for things like propellant burns. This in turn means that cameras and antennas can't be oriented where they need to be all at the same time. This is why New Horizons conducted both its approach maneuvers and its entire science program at Pluto in effective radio blackout; it could only orient [pick one: thruster, camera, antenna] at a time. And while this means we can't monitor the probe while it's doing important stuff, it means that the probe is simpler, lighter, and more robust so it's more likely to survive and get back to us with good data.
posted by Bringer Tom at 3:22 PM on July 4, 2016 [21 favorites]


If you have space-crazy kids like mine and need some activities for your watch party, here's some Juno Coloring Pages! Intense arguments about which crayon to use for the Great Red Spot!

(The second artist there, Ekaterina Smirnova, has a whole series of space coloring pages!)
posted by Eyebrows McGee at 3:38 PM on July 4, 2016 [2 favorites]


the little one pretty much learned to read from the captions on NASA photos that they project between star shows in the dome

I learned to read the Greek alphabet from beer cans while sipping them on the beach in Greece... yeah I'm a waste of space. :(
posted by Pyrogenesis at 3:44 PM on July 4, 2016 [1 favorite]


Metafilter: Mach 215
posted by Oyéah at 4:56 PM on July 4, 2016 [1 favorite]


Oooh, Juno is turning, according to real time sim!
posted by Brandon Blatcher at 5:31 PM on July 4, 2016 [3 favorites]


why did they need to add an extra syllable to "insertion", exactly?

"I'm afraid I can't comment on the name Rain God at this present time, and we are calling him an example of a Spontaneous Para-Causal Meteorological Phenomenon."
"Can you tell us what that means?"

"I'm not altogether sure. Let's be straight here. If we find something we can't understand we like to call it something you can't understand, or indeed pronounce...

"...And if it turns out that you're right, you'll still be wrong, because we will simply call him a ... er, 'Supernormal' -- not paranormal or supernatural because you think you know what those mean now, no, a 'Supernormal Incremental Precipitation Inducer.' We'll probably want to shove a 'Quasi' in there somewhere to protect ourselves. Rain God! Huh, never heard such nonsense in my life. Admittedly, you wouldn't catch me going on holiday with him. Thanks, that'll be all for now, other than to say 'Hi!' to Wonko if he's watching."

-- Douglas Adams, So Long, And Thanks For All The Fish
posted by Ickster at 6:23 PM on July 4, 2016 [3 favorites]




Wow, Jupiter is really filling the screen on the realtime sim now; if you turn the orientation upside down you can watch Juno advancing against the backdrop of the planet.
posted by mediareport at 7:35 PM on July 4, 2016 [1 favorite]


Brandon, the burn has not begun; the host has just said it's still scheduled to start at 11:18.

"All of these times are Earth-received times."

I love it.
posted by mediareport at 7:39 PM on July 4, 2016 [1 favorite]


Interesting, there are two mission control areas, one at JPK and one at Lockheed Martin. Lockheed built the craft, JPL is managing the mission, so they've set up to sites as a sort of backup.

Brandon, the burn has not begun; the host has just said it's still scheduled to start at 11:18.

Hmm, the Real Time SIm says it's begun, I think? It's showing the min engine firing. Perhaps that's just an initial braking firing? But NASA TV says the craft is still positioning itself for the burn.
posted by Brandon Blatcher at 7:43 PM on July 4, 2016


NASA TV (which is also the ustream streams) is explaining that Juno is performing a change of orientation to position the engine for the burn. It has completed the turn, and is now working on taking the wobble out of the spin that was created when the spacecraft changed its orientation.

So, the sequence has begun, but the actual burn still isn't scheduled to begin for about a half hour.
posted by hippybear at 7:46 PM on July 4, 2016


No, according to this tweet from Lakdwalla, there's a 48-minute delay from Spacecraft Event Time to the NASA reporting. So the burn has in fact begun. Here's Lakdwalla:

Bill Harwood is tweeting things in Spacecraft Event Time, so he appears to be ahead of the rest of us by 48 minutes.

And Harwood from 25 minutes ago:

Juno JOI: Now 5 minutes to the start of the JOI burn; the 35-minute burn will be over before confirmation of ignition reaches Earth!

I think. It's rather confusing.
posted by mediareport at 7:50 PM on July 4, 2016




William Harwood ‏@cbs_spacenews 3m3 minutes ago

Juno JOI: The burn should be halfway done; signals confirming ignition still making their way toward Earth

posted by mediareport at 7:52 PM on July 4, 2016




Thanks, Brandon. I saw that behind Gay Yee Hill's shoulder and was wondering what was on the screen.
posted by Beti at 7:54 PM on July 4, 2016


Ah ok, so i'm not crazy. The online simulation shows the burn in progress, but NASA tv is reporting on events at they get actual data from Juno, so there's a lag . The simulation is showing what's expected to be happening RIGHT NOW, while NASA is reporting only the confirmed bits. Sohe signal might have been lost, but we won't know that for 48 minutes.

Man, the instant communication across the galaxy in Star Wars looks really silly now.
posted by Brandon Blatcher at 7:56 PM on July 4, 2016 [3 favorites]


*everyone gets on same page*

Harwood's good right now: @cbs_spacenews
posted by mediareport at 7:59 PM on July 4, 2016 [1 favorite]


NASA's been doing a great job putting women and people of color front and center tonight.
posted by mediareport at 8:03 PM on July 4, 2016 [3 favorites]


Ok, now it gets really weird. The downloadable app (NASA Eyes) is showing Juno getting ready for the burn, while the online version shows the burn already happening.

Schrödinger's spacecraft!

NASA's been doing a great job putting women and people of color front and center tonight.

Yeah, I noticed that too and kudos to them.

Also, the burn is now complete and Juno is changing its rpm to 2 per minute, down from the five it was at during the burn.
posted by Brandon Blatcher at 8:07 PM on July 4, 2016 [1 favorite]


DATA RATE
110.39 kb/sec

FREQUENCY
8.40 GHz

POWER RECEIVED
-164.54 dBm (3.52 x 10-23 kW)

That's a hell of a sensitive piece of equipment.
posted by Talez at 8:11 PM on July 4, 2016 [5 favorites]


nooo, audio is gone from youtube stream, anywhere else I can find it w/out needing a Flash plugin?
posted by indubitable at 8:12 PM on July 4, 2016


I'm really glad I'm watching the NASA video feed. It's educating me about this mission in all kinds of ways. Good on NASA for having prepared such an excellent information package to deliver to the public!
posted by hippybear at 8:12 PM on July 4, 2016 [1 favorite]




Blame Einstein for the confusion over timing. In the Jovian spacetime frame of reference, the burn is halfway over; in the Earth reference, it has not yet begun, It's not that it happened some time ago and we're waiting for the signal to get to us: it really hasn't happened yet. The simulator is predicting our future.

On the other hand, the Youtube audio feed is just being ironic.
posted by Devonian at 8:14 PM on July 4, 2016 [2 favorites]


It's also on NASA TV channel if that's available via your television provider.
posted by hippybear at 8:15 PM on July 4, 2016


Man, this disparate timing is really messing with my head, thank god I'm not high or I'd be spewing "deep" thoughts
posted by Brandon Blatcher at 8:16 PM on July 4, 2016 [2 favorites]


I think its like when they do a Hubble Deep Field picture and see galaxies from billions of years ago. From our time reference, the state of those galaxies is how they appear to us, but if we were in those galaxies, the state of them would be entirely different.

Or something.
posted by hippybear at 8:19 PM on July 4, 2016


MAIN ENGINE TURN ON
posted by indubitable at 8:19 PM on July 4, 2016 [3 favorites]


Confirmation that the main burn has started and the Juno was "alive" as of 48 minutes ago.
posted by Brandon Blatcher at 8:20 PM on July 4, 2016


The desktop sim says the burn started 2 minutes ago, so I don't know anymore, just throwing my clock away, 'cause fuck it.
posted by Brandon Blatcher at 8:21 PM on July 4, 2016 [1 favorite]


There is no way to know what has actually happened to the spacecraft until confirmation (or lack thereof) is received here on Earth, so there is no point in working with any information except for what we know here on Earth. It's not like we can go out there and help it if things go wrong, anyway.
posted by hippybear at 8:23 PM on July 4, 2016


I'm thinking I maybe should have stopped drinking a lot earlier tonight. It's so weird watching NASA scientists pretend it's 48 minutes ago, then occasionally mentioning that it's really now, though.

Anyway, this was cool:

Juno burn was 35 minutes long. That means the train of radio waves containing burn data heading towards Earth is 630 million km head to tail
posted by mediareport at 8:24 PM on July 4, 2016 [2 favorites]


There is no way to know what has actually happened to the spacecraft until confirmation (or lack thereof) is received here on Earth, so there is no point in working with any information except for what we know here on Earth. It's not like we can go out there and help it if things go wrong, anyway.

Actually they know that the main engines started because of the doppler shift from the deceleration.
posted by Talez at 8:25 PM on July 4, 2016


Wow, really nice demonstration of scale w/ the spacecraft stenciled 1:1 on the football field at the Rose Bowl.
posted by indubitable at 8:27 PM on July 4, 2016


Yes, but that doppler shift reached us with a 48 minute delay because of the speed of light and the distance to Jupiter.
posted by hippybear at 8:28 PM on July 4, 2016 [1 favorite]


Actually they know that the main engines started because of the doppler shift from the deceleration.

Yeah, it's stuff like that that has me wondering if we're going to get moments where NASA scientists who know for sure the mission was a success (or failure) will be pretending to the camera that they don't know, and hiding their giggles (or tears).
posted by mediareport at 8:28 PM on July 4, 2016


All these comments and no one has noted we are about to see three Lego figurines arrive at Jupiter? Metafilter, you are disappoint.
posted by Rumple at 8:28 PM on July 4, 2016 [5 favorites]


It's so weird watching NASA scientists pretend it's 48 minutes ago,

It's like watching NBC's plausibly live Olympics.
posted by NorthernLite at 8:32 PM on July 4, 2016 [6 favorites]


Yeah, it's stuff like that that has me wondering if we're going to get moments where NASA scientists who know for sure the mission was a success (or failure) while pretending to the camera that they don't know, and hiding their giggles (or tears).

Yes. If you watch the Curiosity landing, you can tell that many of the scientists knew it was a success a few moments before the Mission lead got all the data points for confirmation and gave the official go to announce it was successful. I called it the nerd shake.
posted by Brandon Blatcher at 8:33 PM on July 4, 2016 [3 favorites]


Wow, 2800 miles above the cloud tops of Jupiter? That's, like... what? from Florida to Vancouver?
posted by hippybear at 8:36 PM on July 4, 2016 [1 favorite]


Also note that this burn will put Juno in a 53 day orbit, which is planned so the engine isn't pushed too hard and it'll give scientists to check out all the instruments, see what's what. In late August, they'll adjust the orbit so it's only 14 days and then really get to work.
posted by Brandon Blatcher at 8:38 PM on July 4, 2016


Orbital capture by Jupiter
posted by indubitable at 8:41 PM on July 4, 2016


That animation of the motion of the moons was pretty excellent.
posted by hippybear at 8:42 PM on July 4, 2016


They don't know anything about what happens at Jupiter until 48 minutes later, because that's how long radio waves take to get between us. They won't get a full report from the spacecraft until it's pointed its antenna back at Earth after it's completed JOI - but it's transmitting a much weaker signal with no data on it from a non-pointing antenna. But we can measure it's frequency back here on Earth, and that frequency will change as the spacecraft's velocity changes (with respect to Earth), so they can compare those changes in velocity with those planned for JOI and tell whether things are working or not.

If the signal goes away or doesn't change its frequency according to plan, then something's gone wrong. The signal is being displayed on a lot of consoles and it's not that hard to read - it's a bump on a graph thats' changing in real time from the Deep Space Network, so everyone in the room will be ticking off the milestones as they're achieved. But we won't know that all the spacecraft systems are OK until it's in orbit and has re-established data contact.
posted by Devonian at 8:44 PM on July 4, 2016 [2 favorites]


Yep, we only needed 20 minutes of burn to reach a usable orbit. We're officially in. Now we just need to verify the 35 minute burn to reach our *desired* orbit.
posted by mediareport at 8:45 PM on July 4, 2016 [1 favorite]




JPL is all standing on their feet in anticipation. hehehe
posted by hippybear at 8:50 PM on July 4, 2016


And now both control centers are starting to get squirrelly.
posted by hippybear at 8:52 PM on July 4, 2016


WOOT!!!!

It's done!
posted by hippybear at 8:53 PM on July 4, 2016


Their mission polo color choice is sort-of unfortunate the way it matches the desks!
posted by Eyebrows McGee at 8:54 PM on July 4, 2016 [2 favorites]


Oh, damn, got something in my eye there for a second.
posted by hippybear at 8:54 PM on July 4, 2016 [3 favorites]


Fucking amazing.
posted by mediareport at 8:54 PM on July 4, 2016


YEAH! Did it, baby! Juno has joined the Jovian Union.
posted by Devonian at 8:55 PM on July 4, 2016 [2 favorites]


Awww I like the guy who's literally crying (I mean other than hippybear). That's totally be me, I'd be the crying rocket scientist.
posted by Eyebrows McGee at 8:55 PM on July 4, 2016 [4 favorites]


They were only one second off from pre burn predictions. God bless the nerds, every one of them.
posted by Brandon Blatcher at 8:55 PM on July 4, 2016 [11 favorites]


'cause you know several of them are already trying to figure out why they were so off.
posted by Brandon Blatcher at 8:56 PM on July 4, 2016 [17 favorites]


Science is pretty fucking amazing.
posted by jferg at 8:56 PM on July 4, 2016


Within a second of nominal.

A couple of days of check-out, instruments on and let the science commence!
posted by Devonian at 8:56 PM on July 4, 2016


'cause you know several of them are already trying to figure out why there so off.

The slide rules have already come out of pockets....
posted by hippybear at 8:57 PM on July 4, 2016




Still not out of the woods yet. Spacecraft has to turn to Sun point, begin charging its batteries again

Have faith!
posted by Brandon Blatcher at 8:58 PM on July 4, 2016


Incidentally, Emily Lakdwalla is a HIGH QUALITY Twitter follow -- she's an excellent journalist with a deep familiarity with and interest space exploration, she retweets great stuff, and she's charming as all heck.
posted by Narrative Priorities at 8:59 PM on July 4, 2016 [7 favorites]


That's why there's another hour of coverage scheduled for the mission coverage. They have to spin the spacecraft down and reorient it.
posted by hippybear at 8:59 PM on July 4, 2016


"Welcome to Jupiter."
posted by NorthernLite at 8:59 PM on July 4, 2016 [1 favorite]


oh, they just killed the stream. The website said it would go on until 10pm Pacific time. Oh well.
posted by hippybear at 9:04 PM on July 4, 2016


For comparison, Cassini has been orbiting since 2004 and will be deliberately crashed into Saturn next September (2017). Juno will only orbit for about 20 months before being crashed into Jupiter. Juno is in a ROUGH NEIGHBORHOOD.

(Out of curiosity, do any of you space super-nerds know how long it takes for NASA to push out updates to its planetarium partners for their solar system shows? (Specifically the UniView software.) My kids will be very eager to see Juno orbiting on the solar system show. I know there's a lag of at least a couple of days and it's a very big data download when they get the updates, but I'm not sure if they push them as needed or on a scheduled basis or what.)
posted by Eyebrows McGee at 9:06 PM on July 4, 2016 [2 favorites]


And the Google doodle was ready.
posted by NorthernLite at 9:06 PM on July 4, 2016 [5 favorites]


I love Lakdwalla's little pokes at the high-level suits in NASA; she's been doing it all day - why are we not seeing the Doppler? Why is the media room no longer getting chatter but only the main public web feed? She's not afraid to nibble a bit on the hand that's feeding her when she thinks it's being stupid.
posted by mediareport at 9:09 PM on July 4, 2016 [1 favorite]


Yeah, we haven't got the spacecraft back yet. One of the things about Juno is that it's sterile, at least as far as we can make it, on the off-chance that things go wrong and it crashes into one of the moons where there's a chance that life might have evolved. Because it'd be a bit of a bummer if when we got there subsequently and found stuff but couldn't tell whether it was native or invasive.

That's the reason Juno will be deliberately crashed into Jupiter at the end of the mission, rather than run until something breaks or runs out, because if we just leave it there there's a 1:10,000 chance it'd hit one of those moons rather than Jupiter, and those odds aren't good enough. But if we lose contact with it or it loses the ability to control itself, then who knows.

So it's not just important for this mission that we get Juno back...
posted by Devonian at 9:10 PM on July 4, 2016 [3 favorites]


WTF happened? I went to heat up a frozen dinner, and the stream is now unrelated to Juno. Bad news or what?
posted by InsertNiftyNameHere at 9:11 PM on July 4, 2016




We live in a fantastic future!
posted by mazola at 9:13 PM on July 4, 2016


Came for happy scientists/engineers and SCIENCE! Am well satisfied. :) (Although I'd really love an explanation of the gigantic cat in this pic (from jscalzi's twitter feed). I mean, I thoroughly approve, being a fan of the bewhiskered ones, but I'm just wondering if it has some Jovian significance.)
posted by longdaysjourney at 9:13 PM on July 4, 2016 [1 favorite]


There's a woman with cat ears on next to the giant cat.

Furries are everywhere. That's my only explanation.
posted by hippybear at 9:18 PM on July 4, 2016 [1 favorite]




Cool, looks like that great real-time simulator (created by private "amateurs," apparently) is gonna keep going.
posted by mediareport at 9:25 PM on July 4, 2016


> Although I'd really love an explanation of the gigantic cat in this pic

John Scalzi is visiting Portland (Oregon) for Westercon 69, and they setup an event with Bobak. Metafilters own Charlie Stross is here also. So we are covered in terms of how to handle either space marines, or space madness.

So you got, Portland, Convention, and Science! as all possible (or combined) reasons for that giant cat.
posted by mrzarquon at 9:25 PM on July 4, 2016 [2 favorites]


Don't know why the stream went off early, but no sign anything's gone wrong.

Post-JOI briefing due in about 35 minutes at 0500 UTC
posted by Devonian at 9:25 PM on July 4, 2016 [1 favorite]


Why is no one confirming that Juno is now facing the sun? WTF, NASA?
posted by mediareport at 9:36 PM on July 4, 2016


Is that odd?
posted by Brandon Blatcher at 9:44 PM on July 4, 2016


The briefing starts soon.. I'm sure there will be answers there for any who want to tune in.
posted by hippybear at 9:47 PM on July 4, 2016


They said a few minutes; it was 25 minutes and press folks were sitting in their cars waiting for something, anything, and were getting nothing. It felt rude.

But it's ok now. Solar panels are go.
posted by mediareport at 9:47 PM on July 4, 2016


On Twitter, NASA just confirmed Juno is facing the sun.
posted by nangar at 9:47 PM on July 4, 2016


This was so much fun to watch unfold--there are happy emotional tweets about spacecraft in English, Turkish, and French (at least) on my timeline right now. I love the global-audience atmosphere of post-Curiosity space missions.

Also, her name is Emily Lakdawalla, with four a's.
posted by karayel at 9:50 PM on July 4, 2016 [3 favorites]


I'm probably the only one who cares, but here's the kind of thing I was seeing from journalists during the odd period of no news.

From Lackdawalla (thanks karayel):

No, no official word. Big room full of media here at JPL who'd love to hear more updates on spacecraft status.

Kenneth Chang ‏@kchangnyt
@elakdawalla So there really is no advantage to being there.

Emily Lakdawalla
@kchangnyt There really is not. If I were at home, I'd be less irritable, because I'd have a glass of wine.

...It's really quite amazing how much like Philae this is. No news, no news, until Mark walked down to talk to us.


I trust her and the others who were there that something off/rude/dumb was going on.
posted by mediareport at 10:01 PM on July 4, 2016 [2 favorites]


And thus mediareport truly lives up to their user name.
posted by hippybear at 10:04 PM on July 4, 2016


Another person here who can recommend @elakdawalla for all your cool space news needs!
posted by tavella at 10:06 PM on July 4, 2016


In case anyone missed it NASA's snapchatting videos. Yesterdays was titled "join us as we get less stupider and learn more about Jupiter"
posted by fshgrl at 10:17 PM on July 4, 2016 [3 favorites]


I remember an interview with a scientist just after his team had successfully completed some experiment or other, and he said, "We're still confused, but now we're confused at a higher level, about much more important things."
posted by Chocolate Pickle at 10:42 PM on July 4, 2016 [12 favorites]


The Juno video of the approach to Jupiter was just uploaded, showing the orbits of all four moons.
posted by mrzarquon at 10:49 PM on July 4, 2016 [2 favorites]


Oh god, who on earth picked that music?

Someone should name a cheese after Vangelis.
posted by CheeseDigestsAll at 10:53 PM on July 4, 2016 [1 favorite]


Fixed?
posted by mazola at 11:08 PM on July 4, 2016


I'm with you all; that music really reeks. Also, the view through Galileo's telescope shows Jupiter half-full. That's impossible, you know; from Earth Jupiter is always fully illuminated by the sun.
posted by Chocolate Pickle at 11:09 PM on July 4, 2016 [2 favorites]


I don't think that's intended to be the view through Galileo's telescope - I think it's meant to be a zoom through the eyepiece to show us what Juno is seeing, since there's no further break to indicate, "Hey, now we are peering at Jupiter from space."
posted by gingerest at 11:20 PM on July 4, 2016


Emily Lakdawalla ‏@elakdawalla 11m11 minutes ago

I'm told there will be a version of the video posted without the music and extra padding some time tonight.
posted by nangar at 11:22 PM on July 4, 2016 [1 favorite]


Thank god, 'cause whoever did that video should be forever kept away from making any sort of movies.
posted by Brandon Blatcher at 11:40 PM on July 4, 2016


Nangar, it was posted quite a while ago.
posted by Chocolate Pickle at 12:01 AM on July 5, 2016


By Jove!

How fucking neato is this?!
posted by futz at 12:04 AM on July 5, 2016


I was dreading checking up on Juno when I woke up this morning; so glad to see that everything worked.
posted by octothorpe at 4:03 AM on July 5, 2016


I fell asleep on the couch last night and missed following along live. I read this thread before anything else to watch it play out. I'm glad you're all here.

Also, count mine among the voices highly recommending Emily Lakdawalla. She's a skilled writer whose enthusiasm for scientific discovery enriches her coverage.
posted by Songdog at 5:19 AM on July 5, 2016 [1 favorite]


The thing that got me was on the JOI trailer, which was very enjoyable except for the lens flare when the POV of the camera was in eclipse behind Jupiter.

I blame JJ Abrams. Which I do anyway. For everything from burnt toast to Brexit. But in this case in particular.
posted by Devonian at 5:24 AM on July 5, 2016 [2 favorites]


We do a lot of stupid stuff, but there are also times when humanity does amazing things. This is one of those times.

And yeesh we don't think small. Jupiter is rough territory even for robots.
posted by sotonohito at 6:25 AM on July 5, 2016 [2 favorites]


Maan, I keep on not hearing about these things until the exciting part is over. When is the next space thing happening, so I can make sure to be at a space-watching party?
posted by Galaxor Nebulon at 6:58 AM on July 5, 2016 [1 favorite]


It's fun to watch in the moment and learn all the details about the mission and the tools while waiting for the big event, but really, you're only watching a bunch of people in a room staring at computer monitors. They're all wearing the same polo shirt with the mission logo, and their desks are all cluttered with papers and geegaws, and without warning, they all look up from their screens and clap and cheer. Hooray! Space stuff just happened 48 minutes ago!
posted by notyou at 7:11 AM on July 5, 2016


When is the next space thing happening, so I can make sure to be at a space-watching party?

There's a manned Soyuz launch to the ISS on July 6th, but that's a fairly routine thing. Here's NASA's upcoming schedule of major launches, with estimates. Here's the schedule for more routine stuff.

China will launch the Tiangong-2 space lab in September, then send a crew to visit it in October.

I don't think anything is landing or arriving off world until about 2018 or 209, probably the Mars InSight lander. But there's no firm date, as its 2016 launch window was missed. It'll probably be late 2020s before a planned American Europa spacecraft arrives at that moon of Saturn. The ESA has the Jupiter Icy Moon Explorer set to arrive in 2030, so long wait there!

September 15, 2017 is the date for the Cassini spacecraft, which is around Saturn, to be de-orbited. Should provide a good look back at the decade plus time in spent in orbit.

March 2017 is the current target date for Space X to launch a live crew to the ISS. It will be the first manned launch from US soil since 2011. Boeing will do similar in February of 2018 with their CST 100 Starliner capsule.

October 2018 have the Jame Webb telescope launching. It's the official successor the Hubble. Probably take it six months or so to get up to speed (total guess on my part) and start sending back photos.

November 2018 should see the first test flight of the SLS rocket, which should be a helluva sight to witness. Plus it'll be sending an unmanned Orion capsule around the Moon, so that should provide lots of pretty pictures.

India MIGHT send their first manned crew into space sometime before 2020, but that's a big if and there is no planned date for such an event.
posted by Brandon Blatcher at 7:36 AM on July 5, 2016 [11 favorites]


It's extremely important to note that instead of landing another spacecraft on Mars with the InSight Lander, we could have gotten a spacecraft floating in one of Titan's methane lakes in 2023. But nooooo, we need another lander on Mars, so...

Yes, I will be bitter about this.
posted by Brandon Blatcher at 7:47 AM on July 5, 2016 [5 favorites]


Every orbit Juno makes will be exciting. Not just because of the pictures it will send back, but because it means Juno will be dipping deeply into Jupiter's magnetic field and coming back out. The mission is scheduled for a couple of years but there's no guarantee it will last that long.
posted by Chocolate Pickle at 8:42 AM on July 5, 2016 [1 favorite]


It's extremely important to note that instead of landing another spacecraft on Mars with the InSight Lander, we could have gotten a spacecraft floating in one of Titan's methane lakes in 2023. But nooooo, we need another lander on Mars, so...

I think Mars excites at the moment because it is reasonably close and has the potential for human missions; so, we're going to go there a lot with probes and everything else. But, it feels like the solar system is just full of wonders as we keep going - Titan yes, but also Encladeus (smallest known body in the solar system that is geological active); Io and Europa around Jupiter - so many things we should be exploring. And who knows what fresh wonders New Horizons will show us with a Kuiper Belt object, and what we will learn from Juno that will prompt even more possible missions.
posted by nubs at 8:57 AM on July 5, 2016 [1 favorite]


"When is the next space thing happening, so I can make sure to be at a space-watching party?"

We are going to have a Cassini Crash Party next year, which I have promised after months and months of begging; my kids are advocating for throwing a model satellite into a cake, so possibly we will do that. Mostly we will have people over to drink and hang out outside in the last nice weather of the year but also we'll sidewalk chalk some solar systems and make some space decor and have a Saturn cake they get to throw Cassini into. (Probably a little Saturn cake to destroy and a larger sheet cake to actually eat in slices.)

But also space happens every night and when you bring cake, it's a party! There's almost certainly an astronomical society near you that does summer night stargazing. Or just DIY it with your friends the next time you've got some clear dark sky going on, and if you're in North America, Earthsky Tonight gives you some good stuff to look for that's typically pretty easy for beginners to spot. You could also have a party to spot the ISS flying over!
posted by Eyebrows McGee at 9:06 AM on July 5, 2016 [7 favorites]




The New Horizons encounter with 2014 MU69 (hopefully given a better name by then) is due in January 2019, if you want to pencil that in.

But I did enjoy the cadence between Voyager and Juno. So many firsts.
posted by Devonian at 9:49 AM on July 5, 2016


will be barreling through space at 215 times the speed of sound.

I spect they're referring to 215 times the SOS in Earth's atmosphere. Which varies depending on temperature, pressure, humidity, etc. Down on the lower level at which jovial Jupiterians iz jumpin, the Jovian atmo pressure is about 10 bars => an SOS three times that of Earth's air. So Juno is only barreling OTOO 70 times the SOS in the STP of the LJA. AOK?
posted by Twang at 11:12 AM on July 5, 2016


I wish I was neighbors with Eyebrows McGee.
posted by Songdog at 3:17 PM on July 5, 2016 [5 favorites]


We all wish we were neighbours with Eyebrows McGee
posted by Devonian at 6:49 AM on July 6, 2016 [2 favorites]


THERE WOULD BE SO MUCH CAKE.
posted by Brandon Blatcher at 6:50 AM on July 6, 2016 [1 favorite]


So...cake meetup at Eyebrows McGee's?
posted by nubs at 8:28 AM on July 6, 2016 [3 favorites]


Cake or no cake, I'd like some more Juno news. Can't find anything about the spacecraft's health or status, and having made such a lot of 'this is the most dangerous part of the mission' I'd expect something by now.
posted by Devonian at 9:45 AM on July 6, 2016


Everything is fine. The team did an AMA on reddit last night.

The initial 53 day orbit has begun, the solar panels are facing the sun, you can see a simulation of where Juno is in relation to Jupiter, Emily Lakdawalla is headed off on vacation and yeah, there's not much news. I don't think the instruments have even been turned back on, the plan is turn on'em later (at the far end of the 53 day orbit, away from all the radiation), check out their general health, calibrate them and then begin the science in August or October, not sure which one. Maybe August, then shorten the orbit to a 14 day one in October?

Have some cake.
posted by Brandon Blatcher at 10:11 AM on July 6, 2016 [1 favorite]


A) buy more cakes people, they have them at the supermarket (especially in the summer when it's too hot to bake!)

B) when we get to Cassini crashing next year I will consider hosting it as a meetup (depending on family situation etc, sometimes kids are impossible)
posted by Eyebrows McGee at 10:35 AM on July 6, 2016 [1 favorite]


Back in low earth orbit, Expedition 49 was just launched and made it orbit just fine. You'll have to scrub the scroller to find the launch, the usual trick to link to a specific time isn't working for some reason. Look in the last quarter of the timeline.

The crew will spend two days testing out various upgrades to the Soyuz spacecraft before docking with the ISS.
posted by Brandon Blatcher at 7:10 PM on July 6, 2016


Oh yeah, there is a spacecraft landing on Mars this year, on October 19th!

It's the Schiaparelli EDM lander, a test lander for the ExoMars mission.
The landing will take place on Meridiani Planum[5] during the dust storm season, which will provide a unique chance to characterize a dust-loaded atmosphere during entry and descent, and to conduct surface measurements associated with a dust-rich environment.[12] Once on the surface, it will measure the wind speed and direction, humidity, pressure and surface temperature, and determine the transparency of the atmosphere.[12] It will also make the first measurements of electrical fields at the planet's surface. A descent camera is included in the payload.
It'll only operate for a few sols, but the data and technology tests will help the ESA and Russia land a rover on Mars in 2020.
posted by Brandon Blatcher at 6:48 AM on July 7, 2016


Why is there so much more radiation around Jupiter than around Saturn?
posted by Chrysostom at 9:55 AM on July 7, 2016


I'd assume there is less radiation around Saturn than Jupiter because Saturn is smaller... but also, Cassini is stationed pretty far away from Saturn, while Juno is going to be going MUCH MUCH closer to Jupiter on each of its orbits, well within the radiation danger zone.
posted by hippybear at 10:11 AM on July 7, 2016


From what I'm gleaning from the Wikipedia article, Cassini's closest approach to Saturn was 12,000 miles above the cloud tops. In contrast, during the orbital insertion maneuver a few days ago, Juno was within 2600 miles of Jupiter's cloud tops.
posted by hippybear at 10:14 AM on July 7, 2016


Saturn is further away from the Sun, so the solar wind is more dissipated when it hits, and has a weaker magnetic field. Still the second strongest in the solar system, though.
posted by Devonian at 10:20 AM on July 7, 2016


Why is there so much more radiation around Jupiter than around Saturn?

According to the Wikipedia article on Jupiter's magnetosphere, you can probably blame its moon Io and the 400 or so active volcanoes there:
Jupiter's internal magnetic field is generated by electrical currents in the planet's outer core, which is composed of liquid metallic hydrogen. Volcanic eruptions on Jupiter's moon Io eject large amounts of sulfur dioxide gas into space, forming a large torus around the planet. Jupiter's magnetic field forces the torus to rotate with the same angular velocity and direction as the planet. The torus in turn loads the magnetic field with plasma, in the process stretching it into a pancake-like structure called a magnetodisk. In effect, Jupiter's magnetosphere is shaped by Io's plasma and its own rotation, rather than by the solar wind like Earth's magnetosphere. Strong currents in the magnetosphere generate permanent aurorae around the planet's poles and intense variable radio emissions, which means that Jupiter can be thought of as a very weak radio pulsar. Jupiter's aurorae have been observed in almost all parts of the electromagnetic spectrum, including infrared, visible, ultraviolet and soft X-rays.
The action of the magnetosphere traps and accelerates particles, producing intense belts of radiation similar to Earth's Van Allen belts, but thousands of times stronger. The interaction of energetic particles with the surfaces of Jupiter's largest moons markedly affects their chemical and physical properties. Those same particles also affect and are affected by the motions of the particles within Jupiter's tenuous planetary ring system. Radiation belts present a significant hazard for spacecraft and potentially to human space travellers.
posted by Brandon Blatcher at 10:33 AM on July 7, 2016 [4 favorites]




Nasa probe sends back first image from its orbit 1.8 BILLION miles away

Am I the only one that thought "Huh, that almost looks like Kerbal Space Program"?
posted by Brandon Blatcher at 6:16 AM on July 13, 2016




"Finley was hired by JPL in 1958, eight months before Congress and President Eisenhower officially created the American space agency. Over her 58-year career there is hardly a NASA mission her work has not touched." Popular Science: THE WOMAN WHO HELPED US HEAR JUNO
posted by hippybear at 10:44 AM on July 18, 2016


ESA says farewell to Philae
posted by nubs at 7:35 AM on July 27, 2016


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