The Toughest Space Probe Ever - How NASA Dropped A Probe Into Jupiter

The Galileo mission to Jupiter featured a space probe which would be dropped into the atmosphere of Jupiter. Because of this planet's gravity the atmosphere probe would experience conditions that no other spacecraft has seen. Entry velocities 7 times faster than those experiences by humans returning from orbit, massively higher temperatures and head fluxes, and no way to test the system fully on Earth.
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[@marcusalexander7088]

20 GIGAWATTS??! You can run 16 Deloreans with that!

[@KeplarDesign]

No my friend, that's Jigawats ur talking about

[@BenjySparky]

1.21

[@juhajuntunen7866]

Did it go backward in time to dinosaur era?

[@penultimateh766]

Actually only 16.52 DeLorean.

[@RCAvhstape]

Extra points for doing some math on this joke.

[@jajssblue]

My Thermodynamics Professor worked at JPL and helped to do the primary calculations for this heat shield. His name is Richard Passamaneck and he worked at Colorado School of Mines later in life. He had some fun stories on how hard it was to model the entry and the margins involved. He did a lot of really interesting things in his life and I was glad to learn from him. I wish I had thought to try to connect him with Scott, but I didn't think of it until after he passed in 2020.

[@samuelscott-wildman5191]

That’s awesome

[@CumulusGranitis]

Thank for that interesting piece of personal history. Getting study under the gentleman who worked on Galileo probe heat shield was a great learning opportunity.

[@jajssblue]

@@CumulusGranitis Yeah, it was great! The guy was a multi-domain genius and easy to learn from. Thermodynamics has a tough reputation that is well deserved, but I took well to it in his class, which I credit to his teaching style. Same with fluids, which I found to actually be harder. Lol.

[@holo_val]

10/10 video, I have always been fascinated by the scientific probe missions through-out history more than any any other kinds of launches. The idea of bits and pieces of spacecraft scattered about the solar system and space for the sole mission of measuring little bits of temperatures and gases to discover the universe always feels so heroic and inspiring.

[@ebrombaugh]

One of my colleagues at a job back in the 1990s had worked at JPL prior and designed the demodulator that received the probe data on the mothership before it was stored on tape and forwarded to Earth. He had some stories to tell about the challenges that posed. We congratulated him when word came back that it had worked successfully.

[@thomas.deliot]

Absolutely love these deep dives into nasa exploration missions ! Thanks Scott :)

[@snickers10m]

The news videos are great but the level of detail he gives in these ones is very inspiring

[@Miata822]

... and the Jovian population still talk today about that mysterious spy drone.

[@adamb8317]

It’s hard to imagine a creature that could survive the pressure required to solidify elemental hydrogen

[@PortRhouse]

“Quoted at reaching Mach 50….” Holy crap that is *screaming* “….which made it sound way slower than it actually was.” 🤯

[@AluminumOxide]

230 g of deceleration is roughly 2.3x more intense than the deceleration in a typical car crash, except a car crash only lasts a split second. That Jupiter Armospheric Probe had to wistand car-crash deceleration for tens of seconds!

[@QuantumHistorian]

That's an amazing way to put it into context. Crashing a car into a wall continuously for a minute.

[@rnbdc]

Yah but we have smart 155mm ammunition (quite big) that has electronics, GPS, actuators for orientation, etc... and survives lunch at thousands of Gs from a howitzer. So it's impressive, but not that much.

[@tinysim]

@@rnbdc I was thinking the same thing. They even had proximity fuses with vacuum tubes developed during WWII that survived canon fire.

[@RCAvhstape]

So in the end Jupiter basically ate the probe and digested it.

[@rogerreger9631]

And gave us a bad yelp review. *sad face*

[@galliumgames3962]

20 GW is the equivalent of the entire electrical grid in a medium-sized country, wow.

[@jakistam1000]

Also, 30 kW/cm^2... I mean, that's insane

[@Inkerflargin]

Where did it get that much power to dissipate when presumably the rocket launching it didn't have the power of a medium sized country?

[@Gregory_Laborde]

@@InkerflarginThat power came from Jupiter sweeping the Probe up into its atmosphere at Jupiter’s orbital velocity. The Probe was effectively standing still in space when Jupiter ‘arrived.’

[@bearlemley]

@@jakistam1000 And 250g’ for an hour!

[@-snyslyk-5678]

About the atmosphere on other planets - today is 40 years since the launch of the Soviet probe "Nova-1" to Venus! It had a balloon probe that separated at an altitude of 55 km from the surface.

[@patrickchase5614]

wrt "Apparently the test system was miswired exactly the same way" at ~14:50... That is a very, very common problem in all aspects of engineering. I like to call it "incestuous testing" i.e. the test and associated fixtures share the same defective DNA (in the form of bad design assumptions) as the real system. It's especially common when the system under test and the test are implemented by the same individual or team, without any external review. They just reinforce their own mistakes instead of finding them. That is exactly why we do integration testing, where we confirm that entire systems behave as expected instead of just testing individual parts. In this case if the computer had been exercised as part of the centrifuge test then the fact that it was interpreting the high- and low-G sensors in reverse would have been easily detected.

[@AndrewBlucher]

This retired IT guy totally agrees!

[@Celestial.132]

"Mach 50, which makes it sound way slower than it was" this is the only context in which mach 50 could possibly be slow

[@T.h.e__T.r.u.t.h]

The nasa tv channel needs to hire you to make programming approachable and understandable now, not saying they dont already do that yet you bring so much more to the table and i thank you for the years of enjoyable content

[@davidgunther8428]

The data rate from Galileo was tragic. I'm glad it sent the data it did.

[@Gregory_Laborde]

The original mission design had Galileo collecting data on its flybys and transmitting that data ‘burstily’ to Earth on its subsequent ‘long orbit’ to the next flyby. With the datarate limited to 10 bps (160 bps max) the Orbiter continuously transmitted data from the previous flyby up until preparations for the next flyby began. In addition to scientists learning to very effectively prioritize which data would be returned first, on-board editing and compression software was added. These improvements greatly increased GLL’s data return. The biggest loss was to long-term monitoring of Jupiter’s weather. No getting around needing lots of pictures for that. These techniques were propagated to future (non-‘crippled’) missions to greatly improve data return volume and efficiency.

[@robinseibel7540]

Tragic, yes, but still more reliable than 9.6k dial-up via AOL.

[@TreeCutterDoug]

What a deep dive! Amazing to think this was possible with the computing power available at the time... It really says a lot about the talent, brilliance and determination of the people that made it happen.

[@AndrewBlucher]

Oh, excellent pun!

[@NoPegs]

WoopWoop! Spacecraft Sunday with Scott! =3

[@Megaddd07]

Another excellent video from Scott

[@GlutenEruption]

Mindblowingly cool to think that a few man made diamond windows may well be lying intact on the surface of Jupiters metallic hydrogen core to this day 🤯

[@Gregory_Laborde]

There was actually a much more serious problem than the ’snot’ on the dummy erase head discovered when the spare DMS (Data Management Subsystem - in the GLL Testbed failed a few hours after the flight problem. An LED used to detect End-of-Tape failed, allowing the clear leader at the end of the tape to travel through the mechanism to trip the beginning-of-tape sensor, locking the tape irretrievably at EOT. Opening the spare DMS to fix this issue allowed engineers Greg Levanas and Mike Johnson to diagnose the stuck tape issue and determine that the tape was almost certainly intact. Later we advanced the tape, demonstrating that it was in fact intact, and then wrapped up the potentially weakened spot in 25 wraps of tape to protect it. That plus the LED issue meant that we could not go to either end of the tape again. The software in the flight computer was modified to only move in playback mode and look for data patterns saved to the tape. These patterns became the new Beginning- and End-of-Tape markers, referred to as ‘New BOT’ and ‘New EOT.’

[@Gregory_Laborde]

Imaginatively.

[@KevinBalch-dt8ot]

The novel “2001: A Space Odyssey” had a probe that fell through Jupiter’s atmosphere on a parachute but it also had a camera.

[@patrickf.4440]

Though it may have had only a limited amount of time to function and be able to show anything (given clouds/clear areas/clouds, etc) a camera would have been nice. One lesson NASA/JPL seemed to have learned here was that all future spacecraft will definitely have cameras on them so that taxpayers will have cool visuals besides all the data.

[@teeteetuu94]

@@patrickf.4440 Seeing how far tech and science advancement have come decades since this mission, I think it's safe to say it is feasible even with current technology.

[@salty_berserker_channel]

Fantastic video Scott 🎉

[@bernhardjordan9200]

That's a slower bitrate than a telegraph

[@jasonlockhart4647]

Wonderful video scott

[@Kostas1983]

Hilarious. I was listening to a conversation about hypersonic flight and I wondered about the speed of the Galileo probe so I googled it five minutes ago. Then this drops...

[@Nilguiri]

¿Coincidence? Yes.

[@giovannifoulmouth7205]

Now NASA must build a probe for Uranus! and it has to go deep!

[@taras3702]

I'm afraid most porn stars are way ahead of you there.....😂

[@markholm7050]

I am ashamed to admit I had forgotten about the Galileo entry probe. Thank you for this excellent video.

[@druspork7737]

Well that was fascinating. Cheers Scott.

[@marcusalexander7088]

Merry Christmas Scott and family.

[@AndrewBlucher]

Thanks Scott. So many details that we didn't hear about at the time. I think you've outdone yourself on this one :-)

[@nopetuber]

Really heartbreaking how Galileo couldn't deploy its high gain antenna!

[@beakytwitch7905]

Awesome report. Thank you ! 😊

[@NaRoonStarrider]

Nice vod Scott learned something new that I did not know about that mission.

[@danielwalker5682]

Great documentary.

[@YippyKiYay]

Amazing story telling 👏

[@AntonioGarcia-ti9wc]

Awesome, one of your best videos! Thank you!

[@sebastianweise4790]

Love that kind of stuff on a sunday late evening, thanks for this gem Scott! ❤😅

[@paulbolus9399]

Thank you Scott!

[@AIJenkins]

Fascinating story, well done Scott. What an amazing journey and certainly a feat of engineering history. Thank you for making my day! 🚀

[@ChristopherDoll]

It makes me happy to think the diamond lens bits made it that far down into Jupiter. Very cool

[@Turbo495]

I was born in 98 so I really appreciate you covering this. As always thanks for all the content!

[@Gregory_Laborde]

The story was that the test harness for the centrifuge test was built by the same people who built the flight harness, from the same drawings so the same error was made, cancelling out the reversed Hi-G and Low-G signals. Lesson learned. I am glad Scott covered this error. I looked for documentation of it years later and found it had been effectively suppressed. As engineers we only learn from our mistakes if we share them.

[@ericfielding2540]

Great explanation as usual. I was only a little surprised that Scott did not mention that the Galileo spacecraft and probe were built at JPL for NASA.

[@Gregory_Laborde]

The Galileo Probe was built by the Hughes Aircraft Company under contract with the NASA Ames Research Center (Mountain View, California). My first flight activity (and first as lead) was to get the Probe released from the Galileo Orbiter, unblocking the 400 N main engine to allow the Orbiter Deflection Maneuver to get the Orbiter off its collision course with Jupiter and onto its orbital insertion trajectory. My office was also right next to the Probe Team’s offices at JPL, so I had many interesting interactions with them Bryon job-related ones. One of my most treasured mementos from my time at JPL is a special Probe Team pin that only very few were issued. RIP Pat Amelia, it was wonderful working with you.

[@Gregory_Laborde]

… beyond job related ones…

[@Gregory_Laborde]

Pat(rick) _Melia_

[@KOZMOuvBORG]

14:59 reminds me of the origin of Murphy's Law. There was a rocket sled experiment being done at Muroc/Edward's AFB where someone wired all the accerometers the wrong way, giving no results and the namesake engineer quipped "If Anything can Go Wrong, It Will".

[@Tamburello_1994]

VGER lives.

[@mamulcahy]

Incredible technology! Thanks for sharing!

[@Jack_Rabbit71]

Gotta love that Stella 90's caterpillar Stach in the build room!

[@CumulusGranitis]

Very nice deep dive into how Jupiter Atmospheric probe, (dropped off by Galileo as it approached Jupiter orbit insertion), survived Jupiter Entry and then what scientific data it gathered before reached "crush depth" at 24 bars pressure and imploded.

[@3800S1]

Finally! I've been waiting for a video on this. Info on the atmospheric probe is sparse at best and most of it exists as the original papers and jpl website from 1995 which has not changed for all these decades.

[@pipcopur]

Thanks for this, always been interested in the Galileo mission. RIP Bill O’Neil, Ed Stone and the others involved in the mission who are no longer with us.

[@fredfred2363]

That is crazy Gs. To even design wiring would be so difficult. Interesting video. 👍🏻🇬🇧

[@mikeissweet]

Simply incredible 😮

[@redcirclesilverx4586]

Thanks Scott, I was a bit to young to remember this time but I absolutely remember learning about Allan hills worm rock and then spent my high school time painting a sojourner panoramic for school after I printed out every image from the panoramic camera and decorated the walls of my bedroom with it.😂

[@vendasch666]

Everything was given us so simply I never realised how many problems did they have to overcome to push us a bit further as a humanity.

[@dvdschaub]

Outstanding!

[@dizbeliefdanbackhouse5807]

It's crazy how they could do that back then, imagine what there must be not tech wise. Thanks Scott 💚

[@BenjySparky]

Scott, you rock! Peace 🤘

[@dakotamiller323]

My mentor professor Dr Eric Klumpe worked as an engineer on Galileo!

[@nagjrcjasonbower]

Nice!!! Keep it up! 🖖

[@General12th]

Hi Scott! Fly safe! Doesn't radiative heating grow much faster with velocity than compression heating? How did the probe's retrograde side not melt under the plasma glow?

[@illygah]

big fan of the new outro

[@nicholasmaude6906]

The atmospheric-probe wasn't crushed by Jupiter's atmosphere, Scott, as it had pressure-equalising valves, the probe instead was cooked as it descended into the hotter, deeper layers before then melting and finally vaporising.

[@taras3702]

During peak heating and declaration, the heat shield reached temperatures high enough to emit X-rays. In short, the entry probe survived what amounts to a massive nuclear explosion before the parachute deployed and the heat shield was jettisoned. The heat shield turned out to have been barely adequate to protect the probe as two thirds of it burned away during entry.

[@davesatxify]

Poetry. sheer poetry. of course the first time i typed that it came out Peotry.. lol. thanks Scott

[@Kazick228]

I always see models of Galileo with the antenna jammed, makes sense as it was jammed. But I noticed now part of the dish has a dent in it. I wonder if that was part of the design or something else.

[@josh3771]

JPL has the most incredible people and engineering

[@vovochen]

Wow. Awe inspiring. I ceel a call towards JPL.

[@Rebar77_real]

Very cool!

[@itburnswhenip]

KSP > KSP2

[@salty_berserker_channel]

It's interesting that what is now becoming the bottleneck of manned interplanetary travel is heat shields. This is a good sign. The delta v problems to go interplanetary are currently being addressed successfully.

[@gustavgans6075]

Wouldnt the unsymmetrical antenna cause vibrations and make Imaging impossible?

[@ururualeksi5082]

It was probably balanced by something inside

[@Gregory_Laborde]

The camera was on the despun side, thus stabilized for imaging. The asymmetrical antenna was pretty low-mass, and the CG of the Orbiter could be adjusted by moving the RTGs (which were _not_ low-mass) in or out using actuators. Interestingly, the mass properties of the Probe had been recorded somewhere and lost, making it impossible to determine the exact positions of the RTGs to be used during the Release (to avoid bumping the Probe as it departed the ‘throat’ of the Orbiter.) Lots of analysis ensued (mass properties of the Orbiter were not lost and the combined performance was well characterized) and reasonable RTG positions selected. Following Release the RTGs were repositioned again (for the last time?) to adjust the CG of the now Probe-less Orbiter.

[@blazingdisciple4070]

What song is playing at the end of your videos? I can't find it anywhere!

[@sebastiaomendonca1477]

I would give anything to see what that re-entry looked like from up close. Can you imagine the plasma?

[@ondrejdvorak5107]

250 G? how does crew handle that?

[@KevinBalch-dt8ot]

How much did the asymmetry of the under-deployed antenna affect the spin stabilization?

[@DosGamerMan]

Changes in the supply chain? So no more asbestos is available?

[@ChuckSwiger]

g-switches - perfect example of Murphy's law.

[@RaimarLunardi]

wait, how Jupiter migrated inwards and why or did it stop???

[@Videoman2000]

If you ever read the the 2001: Space Odyssey book, they describe such a mission there.

[@HensleyTG]

Cool video 📸

[@nicholasmaude6906]

Given how Jupiter's interior is in regards to the atmospheric-probe's fate the end of this video should be "I'm Scott Manley, fry safe"😉😁😈.

[@hyperturbotechnomike]

I always thought Venera was the toughest. Never knew about the jupiter one before.

[@clippership8381]

Smart Guys on that heatshield. BTW I'm looking forward to a video on the lost Intelsat in GEO in Oct 2024

[@arcitejack]

Did we not name the probe??

[@vaughnuhden]

Could we catch some or all that energy while descending through the atmosphere?

[@davidjernigan8161]

There's probably a few chemicals and materials that were used in the Apollo heat shield that are no longer available

[@graemepennell]

20 gigawatts.... 20 gigawatts..... Great scot.... We needed 1.21 for time travel!!!!

[@crackedemerald4930]

how does the probe get crushed? do the instruments and the probe itself all have sealed internal volumes to crush? why couldn't they leave then open or have them open so the pressure equalizes?

[@olasek7972]

Clearly scientific instruments, data transmitters can’t be vented so something must be sealed… you can get pressure to equalize but then you aren’t getting any useful data, plus this isn’t just pressure, forgot about the temperature 😂

[@joshzwies3601]

Have you read the space opera Saga of Seven Suns? The opening scene in the first book is about turning gas giants into artificial stars.

[@Spedley_2142]

Is there anything left of the probe? Could you go and get the remains or has it dissolved/melted away?

[@Jay-cf6dz]

Just like your brain, it melted away

[@olasek7972]

think harder 😮

[@Spedley_2142]

@@Jay-cf6dz Shouldn't you be busy on Twitter?

[@FrisoGorter]

That "hole in the clouds" was nearly the size of our planet at the time.

[@Willbrse]

230g? Kenny Brack be like "hold my beer"

[@yes_head]

Sounds like 'the little probe that... sorta could.'

[@thomasafb]

and years later, the spacecraft followed its probe into Jupiter

[@nickashton3584]

love it

[@maksymilianpasternak8529]

Video length: 21:37 Me: Coincidence? I THINK NOT!

[@mccpcorn2000]

Note to NASA: Next time you do something like this, stick a camera on it!

[@olasek7972]

with 128 bits/second scientific data was far more important than any photos that would probably be not very exciting to begin with

[@mrmadmaxalot]

Was thinking this myself. The tech has progressed so much that we almost certainly would if it were designed today.

[@ImieNazwiskoOK]

Aside from what the first person said, honestly I feel like there wouldn't be that much to see. Aside from reentry (for which the camera would probably need some special protection at the very least from the light alone) it's just going down into the atmosphere.

[@applicablerobot]

New outro music? No no no no no

[@MrEricmopar]

Am I the only one that started playing The Blue Danube in my head, during the spin stabilized segment? 🙂

[@GerardStainsby-s4s]

The random loose particles shown at the probe separation should have straight paths (with, of course, their individual rotations, presumably too small to see at the given scale) rather than the spirals shown... 😉