Slashdot Mirror
Galileo, Consumed by Jupiter
We ran stories about Galileo's impending incineration earlier this month and last November when the plan was decided.
Here is a typical passage from Journey Beyond Selene, about the worst glitch in Galileo's mission, and the beginnings of how it would be worked around. Failures and the engineers who salvage them are the recurring tragic, triumphant story of our missions into space. Reproduced without permission:
With such triply redundant hardware built into their spacecraft, mission planners could feel confident that they had designed a communications system that was almost completely resistant to failure, and for the first eighteen months after Galileo's 1989 launch, there was no reason to assume anything would fail. Finally, on April 11, 1991, when the ship's trajectory had spiraled out as far as the edge of the asteroid belt between Mars and Jupiter, JPL planners decided it was at last probably safe to unlock the high-gain antenna and spread its ribs. It was only then that they'd learn if triply redundant was redundant enough.
Though the deployment of the high-gain system was not a complicated exercise, it was a critical one, and for that reason the chieftans of the Galileo project made sure they were there to watch it happen. On hand at the flight director's console that afternoon were mission director Neal Ausman, deputy mission director Matt Landanow, and project manager Bill O'Neil. O'Neil and Ausman were far and away the higher ranking of the three men, but Landanow, they all knew, was far and away the most knowledgeable. As chief engineer during the Galileo design phase, he had familiarized himself with every strut, nut and rivet of the ship, and could practically describe their placement and purpose from memory alone. If anything went wrong this afternoon, Landanow would likely be the first person to recognize it -- and the first person to come up with a way to fix it.
For the first forty minutes or so after the deployment command went up, O'Neil, Ausman and Landanow had little to do. Like so many other JPL controllers before them, they knew they would have to tolerate the nonnegotiable limits of light speed, waiting twenty minutes as their signal traveled from Pasadena to the spacecraft and then another twenty minutes as it traveled back again. For that entire time their screens told them nothing, flickering merely with the self-evident information that their command had indeed been sent. Finally, after just over the anticipated forty minutes had elapsed, a column of numbers began to blink on the glass. Landanow gave the figures a quick scan and immediately noticed something amiss. He read them again -- a bit more closely -- and this time started to feel downright queasy. The antenna, from all indications, was pulling what the engineers called stall current. The motor was drawing power, the deployment gears were engaged, but the ribs of the umbrella appeared to be going nowhere at all.
"We're stuck," Landanow said flatly.
"How can you tell?" O'Neil asked.
"The current is saturated, something is jammed," Landanow said. "In any event, the antenna's not budging."
Ausman gave the numbers on the screen a read of his own, confirmed what Landanow was saying, and immediately called out to his flight controllers, instructing them to send a second deployment command up to the ship. The engineers complied, and forty minutes later another stall signal came down. A third command yielded a third signal, and a fourth a fourth. With each new report Landanow winced. If he knew this ship -- and he surely did -- he could all but guarantee that whatever was hanging up the antenna was not much: a single too-tight fitting, perhaps, a single protruding bolt, one that was situated in just such a way that it managed to jam all eighteen ribs. If it were somehow possible to transport the Galileo spacecraft to a hangar in Pasadena, Landanow knew he could probably roll over a stepladder, climb up to the antenna, and spring it free with his hands alone. But Galileo was not in a hangar in Pasadena; it was tens of millions of miles away, at the edge of the asteroid belt between Mars and Jupiter, and more elaborate measures would be necessary.
Time Event
________ _____
11:04 a.m. Coast timer initiates probe operation
12:46 p.m. Orbiter flyby of Io (~1000 km) (No imaging or spectral data collected)
2:04 p.m. Energetic Particles Investigation (EPI) begins measuring trapped radiation in a region previously unexplored.
5:04 p.m. Probe entry and data relay
5:05:52 p.m. Pilot parachute deployed
5:05:54 p.m. Main Parachute deployed
5:06:02 p.m. Deceleration module jettisoned
5:06:06 p.m. Direct scientific measurements begin
5:06:15 p.m. Radio transmission to orbiter begins
~5:08 p.m. Visible cloud tops of Jupiter reached
5:12 p.m. Atmospheric pressure the same as Earth's sea-level pressure
5:17 p.m. Second major cloud deck is encountered (uncertain)
5:28 p.m. Water clouds entered (uncertain)
5:34 p.m. Atmospheric temperature equal to room temperature on Earth
5:46 p.m. Probe enters twilight
6:04 p.m. End of baseline mission. Probe may cease to operate due to lack of battery power, attenuation of signal due to atmosphere, or being crushed.
6:19 p.m. Orbiter ceases to receive probe data (if still transmitting)
7:27 p.m. Ignition of Galileo main engine (49 minute duration) to insert into Jovian orbit
Well it has served well - long past how long it was supposed to.
It's history has been plagued with problems, ones it has overcame.
If any spacecraft would show the history and power of space travel, I think this probe is one of them.
I was reading this article earlier and I was thinking what a sickening feeling it must have been when they realised that the main antennae was not going to deploy properly leaving them up the creek so to speak. I think its a brilliant achievent that they managed to recover from this huge setback, reprogram the vehicle, retask the mission to focus on the Jovian moons and still get so much useful information. A very cool piece of engineering improvisation.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
FYI, NASA TV has a live webcast here. UATV is another place to watch as they are rebroadcasting the NASA channel...
Apparently there was also a possibility that Mission Control would be trampled to rubble by a herd of stegosaurs. Glad that didn't happen, either...
Real Daleks don't climb stairs - they level the building.
that show that "faster, better, cheaper" shouldn't mean cutting as many corners as possible while earthside. Galileo was probably one of the top few probes ever on a measure of information learned per dollar spent NOT because we saved money while building it, but because it was built so well that it just kept on transmitting when by all rights it should have gone quiet a long time ago.
The JPL's webcast starts roughly now, and should last about two hours (light delay).
:)
Hehe.. and just so that it doesn't feel left out, that JPL webserver is currently experiencing what its like to get smashed into Jupiter at 48km/s
Good old Slashdot.
"Hey! Unless this is a nude love-in, get the hell off my property!!"
How did you find out my master plan!!!
PINKY! Here, NOW!
Man, that would make a great book.
I've been looking forward to Galileo's collision with Jupiter for weeks. I can't wait to see which one wins!
H4x0r Economist - k33ping d3m0cr4cy l33t 51Nc3 1987
Since Jamie rather thoughtlessly posted a direct link to the JPL real stream and now none of us can see it; please visit NASA's website listing all the alternate feeds for NASA TV and use one of these instead.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Well, good thing the didn't try to land it on Pluto and set the whole planet on fire. You might want to take some nuclear physics at some point as well, it is quite enlightening to learn what being nuclear really means. Hint: It doesn't involve the magical ability to blow up everything it touches.
I read the internet for the articles.
NASA Press Release: Due to an unprecedented amount of web traffic on the announcement of the Galileo space probe's imminent plunge into the Jovian atmosphere, the Galileo comms computing center was brought to its knees. NASA engineers showed their ingenuity once more, as the flood of internet traffic was directed to the Galileo probe itself, heating Transistor QB-2542a, allowing the main antenna to unfold and allow the original planned communication range, in addition to acting as a miniature solar sail to push Galileo on a recovery arc around Jupiter. NASA Galileo Command would like to extend appreciation to Slashdot and its readers for allowing the unqualified successes of the Galileo mission to continue.
...
The JPL's webcast starts roughly now
Crap. All NASA offers is RealPlayer.
Miss seeing Galileo crash into Jupiter
or
Spend thirty minutes clicking half a dozen hidden, misleadingly named submenu checkboxes to retain my privacy. And then spend three days un-doing RealPlayer's attempt to take over my entire system and all file extensions.
Screw it. I won't download any insertions into bodies no matter how heavenly if it's in RealPlayer format. Definitely not gonna start with something's that not porn. I'll catch the 2 minute recap on the news.
Opinions on the Twiddler2 hand-held keyboard?
Maybe it will turn jupiter into a mini-sun, and the ice on Europa will start to melt, and the moon (now a planet) would slowly become habitable
I'm sorry, haven't you heard that Europa is forever off-limits to us?
Opinions on the Twiddler2 hand-held keyboard?
Plunging into ever increasing pressure, no one knows for sure if this will cause a chain reaction, but the potential energy and temperatures are enormous.
Are you fucking nuts? Talk about "argument from ignorance"! "I don't understand the first bit of what I'm talking about, but I'm going to babble on anyhow!"
I will personally guarentee you that vast quantities of plutonium, and for that matter every other known element, already exist in Jupiter. Just because it's a "gas planet" doesn't mean it's made entirely of gas.
Moreover, if anything was going to "set Jupiter off" it would have been set off already! Remember Shoemaker-Levy 9 smacking in Jupiter? That's huge quantities of energy, large enough to roil up clouds larger then Earth itself! And that's nothing compared to what even Earth has seen in its history, let alone the King of Planets. (There's no way to know but personally I'd bet at least one moon-sized impact has hit Jupiter in the past. Your choice of "Jovian moon-sized" or "Earth moon-sized".)
The only "danger" from forty pounds of plutonium several light minutes away are the quantities of hot air it can still generate here back on earth. Get over your pathetic 1950's-era nuclear fears already. It's just matter, not black magic!
Hi, no offense, but this is the most laughable thing I have ever heard.
a) The main fissionable form of plutonium is Pu-239, not Pu-238.
b) Even if this was Pu-239 on board, forty pounds thereof is a borderline critical mass. You would need tampers to make it a good bomb.
c) Even if this was Pu-239 on board and there was enough of it for a critical mass, it is not arranged in a critical geometry that will produce good fission under a Jovian pressure crush.
d) Even if this was Pu-239 in a critical mass in a critical geometry, Galileo lacks the tritium primer required to kickstart a fusion reaction from a fission reaction.
e) Even if Galileo had a working thermonuclear weapon on board, a thermonuclear detonation on Jupiter would not blow up Jupiter, because there isn't enough of an oxygen fraction in the Jovian atmosphere to set the hydrogen afire. Think about it. Jupiter has collided with large asteroids and comets before now. These collisions give off heat considerably in excess of any nuclear detonation. The huge pressures at Jupiter's interior produce heat considerably in excess of any nuclear detonation. If Jupiter could have turned into a star (it cannot) it would have done so by now.
f) Learn more about physics.
H4x0r Economist - k33ping d3m0cr4cy l33t 51Nc3 1987
I heard on the radio that there was a chance the plutonium in the probe was going to ignite Jupiter into a second star, and it would kill/sterilize most humans on Earth! Glad that didn't happen.
I heard that you can't get radio reception in a room lined with tinfoil.
Short version: There is absolutely nothing to worry about. Read on for the long version.
That is because throwing 48 pounds of Pu-238 (which is useless as weapons grade material, Pu-239 is much better for sustaining fission chain reactions) into Jupiter is like tossing a salt shaker into the ocean. Jupiter already has massive radition belts generated by its interactions with the solar wind. It has surely ingested more than 48 pounds of the various isotopes of Uranium from the thousands or millions of meteorite strikes Jupiter has sustained. And the total energy that could be released by complete fission of all of that plutonium into stable elements would insignificant next to the gravitational-potential energy released by the steady contraction of Jupiter's gas clouds that results from the planet's massive gravitational pull. Because of this contraction, Jupiter already releases significantly more energy back into space that it absorbs from the sun.
Finally, with a total mass that is about 0.0001 times that of the Sun, Jupiter is too small to support fusion reactions in its core by about two (2) orders of magnitude. The smallest stars are about 0.08 times the Sun's mass.
I heard on the radio that there was a chance the plutonium in the probe was going to ignite Jupiter into a second star, and it would kill/sterilize most humans on Earth!
I just heard some sad news on talk radio - NASA probe Galileo was incinerated in Jupiter's atmosphere this afternoon. There weren't any more details. I'm sure everyone in the Slashdot community will miss it - even if you didn't enjoy its transmissions, there's no denying its contributions to popular culture. Truly an American icon.
Opinions on the Twiddler2 hand-held keyboard?
"Hey, look we finally got the antenna open.. oh, wait, never mind."
who are those slashdot people? they swept over like Mongol-Tartars.
It's gone. Nothing to see here folks, just move along.
The maneuvering fuel is nearly gone, and the spacecraft components have sustained many tens of times their design tolerances of radiation. Taken together, it's entirely possible that Galileo would soon become uncontrollable and crash somewhere like Eurpoa, where we may one day send probes to search for life. Because Galileo was not sterilized before launch, it would contaminate wherever it ended up, and could cast doubt of any future test results from expeditions there.
(As a testimony to the hardiness of life, microbes on a camera lens or something were brought to and back from the moon, it wasn't until later that they realized someone sneezed on the lens or some nonsense and the damn bugs survived the whole round trip).
While it would be nostalgic to have left Galileo in orbital purgatory around Jupiter, it's not possible to do this with any assurance that it won't later be a hazard. It is fitting, in a way, that Galileo will become part of Jupiter, the target of so much of its (and his) focus. If only NASA would bring the success of this mission into the public spotlight as a way to raise awareness as to its more successful programs.
Coming soon to Saturn - Cassini, July 4, 2004. (Alas, the last of the "great explorer" probes.)
Bush Lies On the Record.
Yah, sure, they crashed this one *on purpose*. They forgot Jupiter was so big is my guess.
Tell me another story, Grampa.
I ain't buyin' it. NASA just screwed up again and arranged the phony paper trail on their website, complete with press releases, as a massive coverup. Hey, if they can make up a Moon Shot (Capricorn One? Galileo 2003? Sure!) then they can definitely cover up a screwup like this one.
First, Afganistan, then Iraq, and now JUPITER!!!
When will this administration stop?!?!?!?
You may not have had a proper subroutine mechanism, you may have had a bizarre instruction set (with a SEX instruction no less), but you were the first processor for which I ever wrote a set of floating point routines. Rest in peace, old friend.
Panurge has posted for the last time. Thanks for the positive moderations.
Briefly, it's because it might otherwise crash into Europe (the moon, not the continent). It has itself discovered that conditions (water) exists on Europe that might habour life (however primitive), and crashing a sattelite from Earth with possible bacteria might contaminate Europe (the moon) with lethal bacteria.
It might sound like far-fetched science fiction - it ain't. It's the official reason for the Jupiter crash.
I'm in a Unix state of mind.
Bzzt. You fail physics. 1) the probe will likely be vaporized into a 1000-km trail of dust by the impact with the atmosphere at 48 km/s. It won't slow down intact and then sink into the core of Jupiter. 2) The temperature reaches the melting point of metal a few thousand kms down into Jupiter. Even if the probe was intact by the time it sank that far, it would melt/dissolve long before it reached the core. 3) The RTG's contain Pu-238, which as has been stated repeatedly, is not suitable as a nuclear explosive. 4) Even if there was an explosion, it is so incredibly miniscule compared to the mass/size of Jupiter that it simply would not matter. 5) Jupiter CANNOT sustain nuclear fusion - it simply lacks the mass. The pressure in the core is far too low to overcome Coulomb repulsion between protons so that they can fuse. The minimum mass of a star that can sustain fusion is approximately 75 Jupiter masses. That is very, very well-understood physics (look up the astronomical tem "brown dwarf").
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
Metis [MEE-tis] is the innermost known satellite of Jupiter. According to this page Metis orbits at a mean distance of 127,969 km with a Mean orbital velocity of 31.57 km/sec. So 48 km/sec is not so ridiculous.
No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
Nonsense. Apparently you missed all the other quotes on this thread, or didn't believe them. Just in case it'll help, here is the math. Note that Jupiter is not even close to half of the mass required for sustained fusion.
At least it didn't get stuck in Uranus.
I think my favorite commentary on it was from Fox news here last night, which noted that if the plutonium core exploded, then "it would disrupt the entire galaxy." This, after a perfectly fine report on Galileo. It was the last sentence of their blurb -- something to give you warm fuzzies, I guess.
I was wondering what level of disturbance would be required before the entire galaxy was "disrupted" -- simply being visible across the entire galaxy, a tremor like an earthquake, or something more sinister? Perhaps Fox needs a galactic Richter scale to better scare the masses. "It's a 0.00009 on the Asimov scale, which doesn't seem like much and we won't feel any effects; but if you were there, you'd be killed, alright!"
That picture is all brown, I guess Gallileo landed in the shit.
http://jesus.everdense.com/