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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.
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!
This spacecraft has been in a very hostile environment for a long time now and to kill it they have to plunge it into the biggest planet in our solarsystem. That is what I call engineering.
The strange thing though is that their site (Nasa) cannot hold up on the preasure from slashdot.
I really HAD another userid
Here is an image of my browser which managed to make it to the webserver in the last minute before Galileo crashed into Jupiter.
http://lucifer.intercosmos.net/g.jpg
It is kind of sad..
and I don't know why.
anime+manga together at last.. in real time.
So, that's 48 km/s relative to what? If it's correct to assume the writer meant "relative to Jupiter," then that is ridiculously fast. IIRC, typical orbits around Earth manage only ~8-10km/s.
Yes, I realize Jupiter is larger than Earth, but still...
IWARS.
People, in general, disappoint me. Politicians even more so.
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.
the saddest part is that the craft went on the blind side of jupiter before it went down. So, we didn't get to see its final transmition. Did some scientist at NASA do that on purpose, to let it die with dignity?
What it also means is we don't actually know for certain that it crashed. I mean, maybe on the blind side it pulled back up, was rescued by a spacecraft, or...who knows! Wasn't ther ean old original Star Trek that went along those lines? An old space probe that went nuts, and spawned a civilization?