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NASA's Odds For Iridium De-Orbit Casualties
Super_Frosty sighted (and cited) this story running on Yahoo! which says, in part, "U.S. space scientists put the odds at nearly 1 in 250 that debris from the proposed burn-up of the world's first global satellite telephone mesh would hit someone on Earth.
The prospects of a casualty from the now-averted mass 'de-orbiting' of the system known as Iridium were spelled out in a previously secret study by the National Aeronautics and
Space Administration." Isn't it nice that this has been put off for a little while? (Oh, and what were your favorite Lotto numbers again?)
Now their space junk is about to come crashing down on Earth, potentially landing on countries with which the U.S. already has difficult diplomatic relations. I mean, accidentally blowing up a Chinese Embassy during a "war" because a CIA Rolodex is out of date is one thing, but crashing a satellite into Beijing would be a completely different story.
If NASA's odds are at all close to reality, is it any wonder that the Department of Defense has stepped in? The next question may be what assurances will need to be in place the next time some company decides it wants to blanket the earth with flying diplomatic disasters. Motorola and its cohorts may have done a great disservice to the cause of commercial space exploitation.
BTW, I should mention that I'm all for ambitious ventures involving science, space, and/or technology. I just wish that the people with the bucks weren't so catastrophically dumb sometimes!
Don't worry, but the time it reaches earth, it will be no larger than a chihuahua's head :)
This is a joke on a Yahoo! television commercial that was broadcast earlier this year. A guy living in a trailer in Quasi sees the report on television, and orders a bunch of pillows from Yahoo to protect himself. Not the most hilarious thing I've ever seen, but it just irks me when people don't understand that something is a joke.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
Everybody puts in money on who they think will get hit by an iridium satellite. Everyone who bets correctly gets to split the money from the pool. Ok I'll start off, I'm putting in 5 dollars on cmdrtaco.
-Stype
-Stype
Bus error -- driver executed.
If the odds of anyone being hit are 1/250, and there are 5 billion people equally likely to be hit, then chances of any particular person being hit are then 1 in 1.25 trillion. This is about as good as the chances that OJ is innocent of his wife's murder.
If there are only 25 million Iridium customers, we have 25E6/5E9 * 1/1.25E12 of a chance of them being hit. This is about as good as the chances of the Florida Supreme court interpreting Roe vrs. Wade retroacitly as meaing that Al Gore's mom must have aborted her son.
The chances of anyone being his may be exadurated to begin with, and the chances of any particular person being hit may vary with location and shielding. I've got my umbrella up, just in case. Stranger things have happened.
Friends don't help friends install M$ junk.
I tried to explain this to my mother once when we were at a campsite waiting for another family to show up.
The probability does not change just because the particular event in question actually happens in a given place and time. The factors involved in computing the probability are not related at all to the way anything eventually happens...that's why it's called probability...it is a prediction of the likelihood of some event.
This probably still doesn't explain it all that well...oh well...my mom never got it either.
"That's Tron. He fights for the Users."
Did you ever think for a moment that the gentleman had epilepsy and a tendency for Grand Mal Seizures?
just = (My)Opinion.toCents();
>If you read Chomsky's stuff you know that a 1:250
>chance that someone will die from iridium debris
>is nothing compared to the huge atrocities that
>go on all around the world.
True, true.
But that being said, I rather there be no chance I'll get hit by a falling Iridium satellite.
Whups, you're right. It's even worse than I first stated. I should have dug up that link before posting.
Yep, putting 72 pounds of plutonium on top of a rocket that blew up twice out of 25 launches is not my idea of a smart move. Not that most slashdotters were very sympathetic to such concerns.
And yep, it is worrisome that there is so much plutonium still in orbit. I don't what else to say about that, except that it sucks.
Free Hans!
No the odds of someone getting hit is then divided by the number of people on the planet for the chance of a personal interraction. But even that produces a number way too high unless you're sailing in the Pacific or Atlantic ignoring shipping advisories.
Realistically the odds of you getting hit personally is probably somewhere in the region of one in several thousands of billions. You'd be wiser to worry about encounters with natural meteors, and even wiser to forget the whole thing and pay more attention the next time you have to walk across the road.
I thought the guys who did the launch math were fired for putting a negative sign in the wrong place. Perhaps they were given the option to resign...
---- Just another spud server.
I'm pretty impressed that the DOD was able to get basically unlimited access for 20,000 phones for $150/month each (this is less than Iridium had planned on charging). They're basically commanding a $5.5B system for $36M/year.
Pretty impressive in light of the $500 hammer stories.
Michael
Do you have ESP?
If there's a 1 in 250 chance that the falling objects will hit someone. The odds are, there's going to be a few ear-bursting near misses, and a small amount of structural damage.
In any event, if you use simple kiddy math, there's a 1 in 1500000000000 chance that a bit will hit YOU. And if you look at all the millions of things that could kill you, this ends up somewhere near the 'insignificant' end of the scale.
--
I will be late for work; a falling star hit my leg and it broke.
Glen Murphy
Well, the basic problem is that the guys who did the launch math have quit, so the guys who did the buisness plan math are in charge.
The latter have been known to make errors.
If the DoD can step in and prevent them from falling back to earth, can't they just give 'em a little boost and send them hurtling out away from Earth? Why is this option not discussed? Am I wrong that this is possible?
"What thou shalt not, I shalt did!" -Bart Simpson
The beauty of it is, assuming that there were about 100 engineers working on the design of the satellite, it's only a 1 in 15 billion chance that one of them gets hit in the head by the debris that they created! :)
I/O Error G-17: Aborting Installation
Sorry for the off topic post. A while ago someone posted a crack for the Infoseek Quickseek bar, i.e., how to change it so it searches a different engine. I'd be much obliged if someone could post that again. Thanks! Oh, *ahem* Linux rules, Microsoft drools!
If it falls the impact itself may not kill someone but it may indirectly cause someone death. Down power lines, explosions, ..etc you get the picture. Alot of deaths happen after a hurricane not only during.
... that what goes up must come down. Somewhere.
"Iridium-Flares" have nothing to do with solar reflections. They are directly related to the satelites brodcast frequencies. They frequencies chosen for communication are near to the ones used for radio telescopes. The satelites aren't always on the mark, so their signals bleed into the images that astronmers are taking of outerspace.
I don't have the Earth escape velocity handy, but suffice to say that with the amount of extra fuel these things carry, all you'd do is move the satellites into a higher orbit. When they deorbit satellites like this, all they're doing is nudging it into a lower orbit, within earth's atmosphere, and then let the air resistance do the rest.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
The DOD picked up the tab on the system for quite a few reasons. the most public being:
A U.S. interagency group led by the Justice Department feared that this ``might create widespread anxiety and lead to a public outcry for ill-considered government action,'' the Pentagon paper said.
But also as the aritcle has said the DOD (collectivly) uses about 3000 of these phones. The deal they struck fall to the tune of 3-million-a month for unlimited airtime for 20000+ users.
To me this seems to be a good deal as they plan to use it so supplment thier current communications infrastructure:
Iridium ``will provide a commercial alternative to our purely military systems,'' said Dave Oliver, principal deputy under secretary of defense for acquisitions, technology and logistics. The Navy, for example, needed more than twice as much such point-to-point secure communications capability as was available, the Pentagon said.
Now 3 mil a month as we all know is MUCH cheaper than say putting more sattlites into space to meet the holes that the DOD has in thier system. This seems to be a cost effective solution that will not only save money but not lay waste to the first world wide communications sattlite system.
Besides I would miss those schweet flares! Ignore the sig
"Don't mess with him, he taunts the happy fun ball."
Imagine a beowolf cluster of these falling out of the sky! :)
.. will the satellites come down in any specific areas or can we expect total global coverage?
----------------------------------- My Other Sig Is Hilarious -----------------------------------
Hello? Doesn't anybody find it strange that the study detailing the dangers was kept secret until after the danger had passed? As far as I'm concerned, this is the end of NASA's credibility and trustworthiness regarding saftey issues. Why the hell were they hiding this report?
Kind of makes those predictions of doom regarding the Cassini probe seem a little less overblown after all. Personally, I was never that comfortable with the idea of putting 27 pounds of plutonium on top of a rocket design that has been known to explode on two separate occasions (once before the Cassini launch and once after). But hey, I guess I'm just a technophobe!
Free Hans!
The sky is falling!!!!
Really.
I'm serious this time.
All Troll + "offtopic" mods are meta moderated as "Unfair", because you abused the system.
here's the commercial for those interested. It's in
Pervert.
Fire and Meat. Yummy.
Of course, if Iridium is technically owned/financed by the US government at this time (see the earlier Slashdot story this week) then I'm sure they'll just kill you or your family before you can make a public scene.
---
seumas.com
If, indeed the chance is 1:250, then I think the DoD spending is justified.
Employee of Inrupt, Project Release Manager and Community Manager for Solid
(Oh, and what were your favorite Lotto numbers again?)
Yeah. I'd never win the lottery, so I don't bother.
But *this*, yeah, I stand a very good chance of "winning" these odds.
My 1976 Dodge Ram will be sitting in my driveway, looking pretty, its chrome heliographing in the sun, the fresh paint sparkling. It's survived 24 years on the road in the Toronto area, over 200,000km, an errant Toyota Camry whose driver had to be extracted from the wreckage of his car with the jaws of life, and more recently a voltage regulator failure that sent my electrical system to the possible world record of 26 volts while I was driving home but didn't do any more damage than blowing out my left headlight.
And then, clear out of the blue, there will come an Iridium satellite.
I know it. I can feel it.
I'm building a bunker.
Fire and Meat. Yummy.
Damn, there I was thinking they were the latest in retro-70's fashion.
...there is no danger, however, as the satellites are now expected to land in Quasi, an uninhabited part of the Australian outback.
NO CARRIER
Actually, I think we can thank NASA on this one. By keeping the report secret until after the DoD buyout happened, they kept the urgency down and thus the price low. As other posters have pointed out, the DoD only paid $72 million for the satellites, which is less than 1% of the total cost of building them in the first place. The only people who really got shafted in the whole Iridium debacle were the investors and venture capitalists who put up the money in the first place. And well, who gives a shit about them? They've got money to burn anyway, so let 'em burn it!
Free Hans!
Seth
$5 / month hosted VPS on linux = awesome!
Actually, like you suggested, the chances are pretty low. Most of China's landmass is very sparsely inhabited. Amazes me, but its true. Ah well, if you can fit 300 million into Indonesia, nothing should suprise me.
Is that the chances that YOU personally will get hit by one of the satellites is about 1.5 trillion to 1. You're much more likely to win the lottery.....even if you DON'T buy a ticket. :)
-Restil
Play with my webcams and lights here
I wonder how much of their infrastructure this will knock out...
-- Pete.
Monochrome - Probably the UK's largest internet BBS
It's a bird! It's a plane! It's....*thunk*. Iridium smacking into my head.
The Blaster Master Fighting for Truth, Justice, and Evil Pie since 1979
Still, I wouldn't have thought that, say, the Pacific would be that hard to hit -- especially for a satellite that's still got heaps of fuel. You could use all this fuel to bring them in on a quite steep descent; a steeper attack into the atmosphere would make things more predictable, I think.
1 in 250 of hitting someone? If you think about it, the odds of hitting someone being that high would mean that the odds of it hitting something at all would be pretty huge. Maybe not a person, but a building, a car, etc. Seems that this will probably be on the news when it happens because of the choas it might cause, and of course the obligatory paranoia from the average person that will follow.
This Wiki Feeds You TV and Anime - vidwiki.org
Now, obviously, if someone got hit and killed (uhm...yeah, you wouldn't think it would just disfigure them, would you?) then there would be legal liability. But, other than that, does anyone know if they could have been legally prevented from doing a mass "de-orbiting"? Could a country prevent them from doing it just because it could potentially endanger their citizens?
1-in-249 means it's unlikely, but not vastly improbable, and it seems a bit disturbing that a company could do something that would ("only") have a 0.4% chance of killing someone.
-- dR.fuZZo
If it were a 1 in 250 chance that it would kill Fidel Castro or Saddam Hussein, the USG would put ten more Iridium networks in space for the express purpose of de-orbiting them.
Homer Simpson?
In an unrelated note, one of Pentagon officials voiced his excitement about new super secret weapon system that is going to be used as an anti-terrorist measure. First tests are scheduled for early next year. "We're going to crush that evil terrorist organization led by Laden once and for all ! They would think that sky is falling !".
However, we were not able to get an explanation about "falling sky"; "it is a secret, you know", we were told.
Also, we were informed by one of our sources, close to Pentagon, that there seem to be a huge demand for hard working hats among US military officials.
However, we still don't know either these two facts are related.
--
--
On scale from -14 to 56 this post is '-15, Nonexistent'
Ok fine the chances are 1:250, but when it hits you the chances are 100% isn,t it? So we can't just let it go quoting some silly ratios.
There's always sufficient, but not always at the right place nor for the right folks.
I mean, he's one of the only people I know (true fact) who survived a plane crashing into his parent's house.
... we can only hope ...
Will lightning strike twice
Will in Seattle
Back in 1979 when Skylab was comming down, the odds, IIRC, were as follows...
150 to 1 that someone somewhere would be hit. So 250 to 1 seems an improvement in accuracy. (Or worse accuracy, depending on POV.)
150,000 to 1 (or somesuch, I don't recall as clearly) that you personally would be hit. (The first 150 to 1, though I recall vividly.)
Also at the time, newscasters were fond of pointing out that if you check your homeowner's policy, it usually specifically states that it covers damage caused by falliing spacecraft.
I'll see your senator, and I'll raise you two judges.
Maybe this should be a sign to NASA or someone that a concerted space junk pickup program should be initiated. Someone needs to take the initiative here. I was looking at a map of where man made objects are orbiting, and they were extremely concentrated around the equator. I know that's still a big circle, but eventually this will become a problem. Sure the space shuttle could pick these things up and bring them home, but isn't there an easy way to break them up into smaller pieces and deorbot them without launching and relaunching the vehicle that does this? Maybe an orbiting arm that can rip old satelites apart and drop the pieces one at a time. Any ideas?
Nate
THIS SPACE FOR RENT
IANAA (I Am Not An Astrophysicist) but, is it possible that these critters could be deorbited in a way to maximise the chance that they could survive reentry? Depending on how well they could be aimed, that would give the Pentagon 74 brand new orbiting bombs...
Just an idea, not sure how feasible it is.
"Fear is the rootkit of democracy.." Blarkon
I believe it is industry standard to undertake controlled de-orbiting manauvers to avoid the most populated areas. I suppose Iridium's financial myopia may have also precluded this but that is extremely neglegent. As you can see Russia is taking great pains to make sure Mir doesn't hit anyone when (if) it comes down. And if you think thats bad, imagine what they're going to have to do with the ISS when it becomes too dangerous to live in! Still, if we didn't have so many damn people in the world the odds would be a lot lower.
That "Rocket a Day" plan reminds me of what Craig McCaw et al plan for the Teledesic network. They plan to launch 288 satellites, and McCaw talks about treating it more like a mass-production scenario than has been the case for other satellites and their launches.
At the moment there's about 20 000 known pieces of space junk and each piece is very carefully tracked. If a piece as small as a coin hits a satellite, at orbit speed, it's bye bye satellite. NASA monitors the path of every little piece and steers the satellites through them. And yes, they do have insurance in case a piece falls back to earth and hits someone. (I think the odds are much smaller that the article claims tho).
Besides, the odds of any individual satellite hitting someone is only on the order of 1 in 20,000, which is quite reasonable.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
Keep in mind that this is the odds of _a_ person dying out of billions. Compare the odds of _a_ person dying in the next 14 months from:
- automobile related incidents
- a plane crash
- power line electrocution
- medical error
- heating fuel fires
Just about any technology has risks far more likely than satellite related death.
People blow these things *way* out of proportion.
...which is to say that the odds that any one particular person is going to get hit by a bit of the Iridium system are 1 in 250 in 6 billion, or, uh... 1 in 1.5e+12. That number doesn't really scare me... I guess I still have to go Christmas shopping.
./?
Slashdot keeps saying "Lameness filter encountered. Post Aborted" when I preview. Since when was lameness out of place here on
Tell that to the Hawaiians.
I win.
Mod me down and I will become more powerful than you can possibly imagine!
Where do your tax dollars go? I mean, what country? If I live in Russia, do your tax dollars go towards keeping secrets from me? You bet. I'm sure if letting the secret out benefitted your country (some random unamed one) they would let you know. And obviously since you could be from any country, it shows that telling 1 (random unamed countries) tax payer would let secrets out to the whole world.
Check your math. It's much easier to calculate the probablility that no one gets hit and subtract that from 1. 1 - (1 - 1/18405)^74 = .004013 or 1/249.2 which was probably rounded to 1/250 so that the reporters would be too confused.
The lesson: Don't do a hairy sum when a simpler calculation will do.
I have discovered a truly marvelous sig, unfortunately the sig limit is too small to contain i
Could the US Defence Dept. be thinking these satellites may come in handy for testing out the proposed missile shield? In a few years they may want to deorbit them into their test range.
There were what? 70 something satellites. So are those odds 1:250 for each one, or the entire batch? If they are for each one, then thats not good... I guess the DoD really did buy it to protect us. =oP
-- You canna change the laws of physics, Captain; I've got to have thirty minutes!
All working satellites have attitude jets and a limited fuel supply to deal with life's little calamities - but that has to run out sometime.
Personally, I think this 1 in 250 figure is highly suspicious. There's a lot of ocean out there, and I'd be willing to guess that they've got a reasonable amount of maneuverability to the point that they can drop one of these within a few thousand square miles of ocean. Surely there's plenty of such spots in the Pacific that don't hit an island, and probably they ought to be able to miss shipping lanes too.
--
--
Do I look like I speak for my employer?
Damnit, I've worked for Ma M before, and if my l/p is still working at my old offices, maybe I can reprogram the satellites to deorbit right on 1 Microsoft Way, Redmond, WA. :)
Suckers. You make our machines crash, time for us to make something crash on YOU! Muahahahaha!
As I'm writing this there are about 160 posts in this thread. So if we go on and hit the 250 threshold one of us is going to be hit by a falling iridipice of iridium?! Did i just hear A. Morisette singing?
Google says it's Kramer.
Right now I'm seeing a banner ad on Slashdot that has the read-ends of a bunch of cartoon animals, with the punchline "What does your backend look like?" Given the place where they're advertising, they really should've had the goatse.cx "back-end" in the ad too...
Who's responsible for this mess? 250 to 1 is downright terrifying. If anything happens, the money hungry CEOs and large stockholders should do some jailtime for manslaughter and gross-negligence. Motorola will just get away scott-free with perhaps a well-crafted "oops" PR statement.
You'd think letting big corporations cheat consumers and pollute the planet would be enough, now they seemingly have the right to rain hot metal on our heads.
What goes up must comes down, unless you reallly really throw it hard. Funny how /. moderators take an ignorant suggestion and boost it up so more people can see it, while few will see this post because I am too lazy to register.
By the way, these probability numbers NASA cites are absolute rubbish.
You forgot to mention that the satellite survives with solar panels intact.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
Wow! 1 in 250 chance of somebody getting hit!? The odds of winning the powerball lottery here in Louisiana are something in the range of 1 in 80M. But in all reality, the odds of an Iridium satellite actually hitting me are really quite low. Just by using basic combinatorics, one can easily see that for any one particular person there is only approximately a 1 in 1.5 trillion chance of them getting hit by an Iridium satellite. See, I really do have a better chance of winning the lottery! (Although, since I practically failed my last test, somebody probably should check my math.)
--------------------------------------
If Murphy's Law can go wrong, it will.
TWICE
Being struck the first time gave me my incredible super powers and let me be an incredible fighting machine for the forces of good. The second time it was an elaborate scheme by the evil doctor Smelgor to take my powers away, but I was completely coated in latex at the time, so it foiled his plan.
Mod me down and I will become more powerful than you can possibly imagine!
But that velocity thang is a motherfucker. Bullets aren't very big either...
Why yes, I AM a rocket scientist!
Several years ago when I was commuting regularly on the Metro near Arlington, VA; there was a guy who took the same train who always wore a helmet. It even had a special plexiglass shield for the face. He did not appear to be mentally retarded--just strange.
The helmet may or may not have protected him from any falling objects, but it certainly protected him from strangers. Nobody went near the guy.
Anyhow, if there is a subway nearby, I would think that's enough to protect you from the debris.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
Umm..correct me if I'm wrong but don't we have some anti-satellite Dept of Defense weapons? I say we test our technology (lasers, missiles, BFG9000, whatever...) and use this space junk for target practice! And hey, if it works, maybe the government can actually clean up space rather than just "tracking" the bilions of pieces of space trash. Okay, I'll admit, as a college student we just let our trash sit there growing flies and fungus, but if I had a missile I wouldn't hesitate to blow it up! ... to usher in the new Millenium and possibly the completion of most of the ISS.
On another note...sure they say that the MIR sattelite is gonna land safely out in the Pacific...but I live right smack in the middle of the Pacific! And I don't wanna die from a stupid old space station falling from the sky; especially when we could have blown it up during New Years celebration
Well, I guess it gives us a good excuse to test our fall-out shelters and air-raid sirens.
-jedi_gras
I don't wanna die!!!
Remember, the
<QUOTE source="http://www.discover.com/">
Objects more than a half-mile wide-- which strike Earth every 250,000 years or so-- would touch off firestorms followed by global cooling from dust kicked up by the impact.
</QUOTE>
OMG! Hell is upon us! The sky will rain bright flashy fireballs and bring on the end of humanity!
Well I guess satellites aren't a half-mile wide. Nevermind.
Execute? [Y/N] _
It wasn't really the satellite that killed him, it was dating that woman, who was just bad luck. I mean, look at her past several boyfriends! black widow that one.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
As in "accidentally" blew up the embassy. But thanks for the update, I hadn't heard that explanation.
Nope, totally wrong, I'm afraid.
I've seen an Iridium flare (once).
The frequencies they use are really far away from radio-astronomy frequencies.
How many radio astronomers does it take to change a lightbulb?
None, they're not into all that shortwave stuff.
Putting up world-wide satellite phone network: $200 million
Monthly service fee: $2,100
Yearly cost to taxpayers for keeping the system in place: $340
Getting hit on the head by a world-wide satellite phone network: priceless
Any sufficiently well-organized community is indistinguishable from Government.
I'm absolutely sick of reading the same shit over and over in /.. Much of the dot is very good reading, and usually good discussion, but when the same shit appears twice?? Don't you read each other's posts??
:)))
My great uncle has his funeral today and I come home completely topped off the Scotch, and this is what I have to read!!!
The odds of there being someone hit at all are 1 in 250.
Hmmm. Well, I suspect the statistics suggested in the joke still stand unless Iridium had ~24 million customers.
Now, what are the odds it'll hit a former Iridium customer...
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Some people have a way with words, and some people, um, thingy.
Nice strawman, now how do those odds compare to anything about debris and re-entry? Not at all.
The facts are the 250 to 1 is amongst the worst if not the worst odds in re-entry history. Using your "logic" why care about death when eventually we're all gonna die?
*roll*
Odds of winning Oregon Megabucks (4 out of 6 numbers matched, estimated prize $23.70): 1 in 335 . --Oregon Lottery
The odds are 1 in 496,870 that this participant will find the key before anyone else does. --Distributed.net.
Alright! So I'm more likely to get hit by a deorbiting satellite than winning $25 from the State or finding the winning key to RC5!
--
Help us build a better map!
"We ain't got no shelter-ree-nees" -- Moe Syzlak "Lets burn down the observatory so this never happens again!"
1,529,410,500,000 to 1.
I doubt that even lottery tickets seem reasonable compared to this number.
The odds of a random person being struck by a piece are very small. The odds of there being someone hit at all are 1 in 250. Therefore you need to compare it with the odds of there existing an Iridium customer on the planet.
Technicalities....
If the odds are 1 in 250 of it hitting someone, and there are 5,000,000,000 people on earth wouldn't that mean 20,000,000 people can expect to get nailed in the noodle by an Iriduim bits?
I'm a writer, a poet, a genius, I know it. I don't buy software, I grow it.
Again, I have no idea why they insist on downing these things. For a little less orbital debris? Since they presumably actually work, why doesn't the government just buy them; even if they don't use them right this second they can maintain their orbits until a time when they will be useful...
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You need a lot of extra energy to move something into infinite space. Don't forget that these satellites are still quite close to the earth, (about 100-200 miles from the surface). Compared to the size of the earth that is still pretty close, and gravity is still quite strong up there.
It may seem things are 'weightless' in orbit, but that's not true. The gravity is still present, but the satellites are basically in a never ending free fall. If you want to climb into a higher orbit, you'd still have to counteract 90% of the earth's gravity. Once you're a couple of thousand miles away, it gets a lot easier, though.
Moving them in a higher orbit has tremendous costs associated with them. If not, the space shuttle could just visit geostationary satellites. The space shuttle never does that. It only stays in the lower orbits, simply because it doesn't have the fuel to go up that high.
The article states that there is a 1 in 250 chance a piece of debris will hit somebody. This means that any one person has a 1 in 250 * 6 billion = 1.5 trillion chance of getting nailed.
If anyone's worried about this, they should coat themselves immediately with liquid rubber (available at hardware stores) to protect against lightning, ebola and cooties.
*** Proven iconoclast, aspiring epicurean ***
I am one of the engineers who does this sort of statistical analysis for NASA. I do not work for NASA, but I work for a NASA contractor.
Anyway, this sort of thing is blown way out of proportion. I cannot verbalize how amazingly arbitrary these calculations are. There are 2 packages that are primary used to determine the probabilities of impact. The first is DAS, it was written in 1990. The second is ORSAT, slightly newer than DAS.
Further information can be found at orbitaldebris.jsc.nasa.gov
I would actually start debunking this entire thing right now (if anyone here could see the confidence bounds on these calculations, you would shit yourself, they are so innaccurate), but I won't (debunk them). Nick Johnson is a co-worker and has apparently approved the number. He has basically led the field for the last 10 years, and he is very knowledgable, so there is some fragment of truth to the article (but not much).
regards
Your Friendly
NASA Contractor Man
While you often hear "you can't put a value on a human life," we do it all the time. Juries do it when they award damages for deaths. We do it ourselves, probabilistically, when we decide how much various safety features are worth to us in a car. Or which airline to ride...lots of people will take ValuJet (now AirTran) at half the cost of reputable airlines despite their safety record.
:-)
Let's put a value on human life of, say, $10 million, for the sake of argument. (US juries seem to value US lives at $1 or $2 million, so $10 million worldwide leaves a big margin of error). So Iridium will pay $10 million if someone gets hit. They're staring at a 1:250 chance (dubious, but that's NASA's guess) at paying that. Then they're expected cost of hitting people is $10,000,000/250, or $40,000. Now do you think they can find a way of launching 74 satellites into higher orbits for less than $40,000?
Damn would it be ironic if I was the one who got hit.
So where can one hide when they do de-orbit them?
Since the things might land in the Australian outback, I wonder whether or not any of the Survivor 2 contestants will get hit...
The real problem is not someone being hit by them. It's people trying to avoid being hit by them. Think about the PR situation. By the time 10 or so of them had hit, someone would have had pieces to show on worldwide TV. Since the re-entry points are roughly predictable, this would produce a demand for preventive evacuations of target areas. That would cost billions and kill more people in traffic accidents than any possible reentry problem.
I know this doesn't help the problems with Iridium, but, maybe in the future, the genuises that design these things could have the foresight to include an explosive device of some sort that could detonate upon reentry so that there are much smaller pieces of deorbiting satellite to deal with. Such a device wouldn't have to be huge - satellites could be designed to fragment in to smaller pieces. The whole thing could burn up without a piece hitting the ground.
Ahhhhhhhh, the atmosphere, ahhhhhhhhh.
Out of order? Fuck! Even in the future nothing works! - Dark Helmet (Rick Moranis) "Spaceballs"
What would it take to send a few rockets out and nudge the satelites in the other direction; e.g. out into space. We've already put a ton of space junk up in and around Earth's orbit, but I would hate to see someone die simply because we couldn't push these things out into the limitless infinity of space.
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
She was a cutie.
That satellite had a part in his death though! :-)
Although, from what I know of the orbital inclinations of satellites that do scientific reseach, they aren't high enough to make it to those (Alaskan) latitudes. It would have had to have been a spy satellite in a polar orbit (90 degree orbital inclintation) thaty killed him. And if that were the case the feds would have impounded his body since it had melded with the satellite! :-)
Rich...
Ignore Alien Orders
--
Once again, an effort to study an event was funded by tax dollars while the results were kept secret. We need laws to open up to the public any research paid for with tax dollars... we paid for it once, we should have free access to it.
So, following your excellent grasp of probability theory.
There is a 1 in 6 chance of rolling a 6 on a dice, but when you roll a 6 it becomes 100%.
Therefore, every subsequent roll of the dice will also roll a 6 won't it since it has a 100% chance.
Or have I been quoting some silly ratios?
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. (Einstein)
No. The top of my list is to go peacefully, in my sleep, like my grandfather did. Not screaming in terror like the passengers in his car.
Actually, in bed, of old age, surrounded by grieving descendants, would be better than getting hit by space junk!
Best Slashdot Co
Hi! This is the Sig, blatantly attached to the end of this comment.
The odds of hitting a human is nearly 4 tenths of one percent. That is really quite good odds of a human getting hit since I'm sure they removed all odds of chances of falling into the ocean before they released this data.
The numeric odds with the data given that one if the units hits a Chinese person is almost 2% if my brain is working properly on this foggy monday morning...
People in India aren't much better off.
Oh really,
/ 03 -31-00.htm
s ho p_8-13-98/Iridium_Flares.pdf
well then I guess these NASA astronomers are wrong.
http://antwrp.gsfc.nasa.gov/apod/ap980402.html
http://pao.gsfc.nasa.gov/gsfc/educ/science/2000
http://mcauley1.grc.nasa.gov/ISU/NOTES-LEO_Work
So, what do you base your definition on?
This leakage is real, and it is a problem, and I look forward to Iridium's demise because of it. But it's not what Iridium flares are. The term "Iridium flare" refers, as the poster indicated, to visible spectrum sunlight reflected by the satellites.
I think you're thinking of Puerto Rico, or the US Virgin Islands. I'm pretty sure Hawaii (like Alaska) is a "real state". FWIW, hawaii.gov Calls Hawaii the "Aloha state".
This has got to be a load. How many meteors end up as meteoroids per day? As far as I know, there's never been any confirmed human death by meteoroid. Why would a mere 74 satellites pose such a threat when no one in recorded history has been provably killed by anything falling from space?
The only certainty is entropy.
While you were posting that a couple hundred people died of hunger, probably a few thousand died of curable diseases. Meanwhile you fret about a 250:1 chance of someone dying.
While Chomsky sometimes has good points, Iridium has burned through somewhere near ten billion dollars of investor cash and has nothing to show for it. The DoD is offering to buy the satellites for $72 million, which is less than 1% of the cost to build the network. I would hardly call this a bailout. The DoD's money is a drop in the bucket compared to the drenching which the bond and stockholders are receiving.
If you read Chomsky's stuff you know that a 1:250 chance that someone will die from iridium debris is nothing compared to the huge atrocities that go on all around the world.
Last I checked, though this could change if Bush becomes president, you could plunk this thing down on 70% of the Earth and not have to worry about hitting anything except fish. Are the same idiots who concieved Iridium going to be the ones firing them down onto the other 30%? Cause it seems to me like taking object A, shooting it in an almost perfectly Newtonian environment (space) towards point B, with acceleration due to gravity G already known, etc. etc., should be a pretty easy math problem to work out. Especially if you already figured out a way to build them, blast them into space atop what amounts to a huge stick of dynamite, position them into geosynchronous orbit, and, oh yeah, provide phone service for the entire world. Can someone elaborate as to how in the world they could possibly de-orbit one of these things into my back yard?
I think there is a world market for maybe five personal web logs.
If they don't get it right, and won't hit anyone they'll get a second try with MIR.....
- if you love something, set it free; if it doesn't come back, hunt it down and kill it
That is sooo cool! Seriously. I mean, of all the ways to go, isn't getting hit with an Iridium satellite at the top of you list?
This is exactly why we all need either helmets or umbrellas. To keep from getting hit by debris falling from the sky. I was saved just last week from a flaming meteor because I was wearing my helmet. "The world's going to end" "Oh? Nice day for it."
Mod me down and I will become more powerful than you can possibly imagine!
1 - ((1 - 0.0000075) ^ 518)
Numerically, the results are 1 in 257.9 for the correct method and 1 in 257.4 for your incorrect method; with small probabilities and small numbers of events, your method is a good approximation. (It becomes a problem when p*n isn't << 1.)
I actually did the calculation correctly, and then decided to post the version I did (which actually calculates the expected number of events) because I thought it was easier to explain. And, I knew the error I introduced by approximating was unimportant, given the uncertainty in my input numbers and that my goal of evaluating NASA's calculation. But I guess I've now forfeited the high ground when I complain about journalistic oversimplification.
The article above says "nearly 1 in 250", which implies that the odds are below this, but near this. The actual odds are "1 in 249", which are greater odds, not lesser odds (meaning, more likely than 1 in 250, not less likely). You could've avoided the whole thing by saying "about 1 in 250", or even "about 0.4%".
*sigh
--Joe--
Program Intellivision!
Program Intellivision!
heh
The article states "Someone." This is scary since human cover a very small percentage of the earth's surface.
Cheers.
As long as people don't overlap, it doesn't matter how uneven the population density is. If a sattelite falls somewhere in china, it's chance of hitting someone is (number of people)*(area of one person)/(area of china), and likewise for anywhere else.
What were the odds of a random person being an Iridium customer? 100-million-to-one?
cheers,
mike
Comment removed based on user account deletion
So as to make the odds as publicly favorable as possible.
You can't really believe that they wouldn't factor in the 70 some percent of ocean coverage into the computer model before they gave us these numbers.
if a satellite falls in the uninhabited outback does it make a sound?
Arm yourself with knowledge.
When I say "X is near Y", that just means they're in the same proximity. When I say "X is nearly Y", that means that X is almost Y, but not quite. When referring to numerical quantities, this can be explained like so:
See the difference?
--Joe--
Program Intellivision!
Program Intellivision!
Now, the area of the earth is about 5.6e+15 square feet, and the population is about 6e+9 people. Assume each person takes occupies 7 sq ft, without overlap. Then 0.00075% of the earth's surface is covered by people. Multiply that by 518 chances and you get about 1 in 257.
An interesting variation: assume that each person has a 100 sq ft region in which impacts could kill or injure them, e.g. by knocking the roof in or scattering debris. These regions cover 0.01% of the globe. There's about 1 chance in 18 that one of the pieces will hit one region.
I assumed that the re-entries were uniformly distributed; the NASA study assumed that the re-entries were untargeted -- presumably NASA excluded the polar regions which aren't under the orbits. And they may have made different assumptions about area occupied by each person and number of pieces per satellite.
In fact, my guess is that this "study" was done by one person in an hour or so, mostly spent looking through the Iridium parts lists. "memo" is probably a more accurate term.
Of course, as other posters have pointed out, these odds drop by 2-3 orders of magnitude if the satellites can hit a target the size of the pacific.
I play pick-3. My numbers are are 32, 24, 32.
tiamat
67.5% Slashdot Pure I guess I need to work on that....
You realize of course that blowing things up in space with a missile would result in MORE debris (both the sattelite bits and the missile bits), right? Many of which will be too small to track.
Some of those little chunks of metal are likely to be whipping about at even higher velocity after the blast, endangering other sattelites and anything we send up there.
Blowing things up in space may look cool on a movie screen but in reality, turning the ionosphere into a meat grinder is a really bad idea.
---
Where can the word be found, where can the word resound? Not here, there is not enough silence.
"Where shall the word be found, where will the word resound? Not here, there is not enough silence." -T.S. Eliot
A US agency spending big bucks to support a falling satelite. Wonder how much "additional" equipmet they have in there?
The odds are 1 in 250 that one of the 60-odd satellites will hit SOMEONE. This does not mean that YOU have a 1 in 250 chance of being hit. This means that there is a 1 in 250 chance that a falling satellite will hit 1 of ~7 billion people on earth. The odds that one will hit YOU are 1 in 250*7x10^12 or ... 1 in 1.75 trillion. Yes, that's right. There is a one in one trillion chance that Motorla will kill you with a piece of falling phone equiment. Get over it.
Also, the Iridium orbits will decay into orbits that cross the path of the space station and other manned spacecraft; Iridium satellites are all in low polar orbits. As these orbits decay naturally, they will be at similar altitudes to the manned systems. While a 10lb titanium fuel tank might damage a car that it falls onto somewhat, a 1000lb satellite would vaporize (literally) the space station.
The bigger question is 'why were these satellites allowed to be launched at all?' This (imho flawed) analysis could have been done before the satellites were launched. It was obvious from the beginning that they would deorbit relatively soon. If it is an unacceptable risk now, it was certainly just as unacceptable then.
thad
I love Mondays. On a Monday, anything is possible.
Rich...
Ignore Alien Orders
Their number of 1 in 250 is obviously calculated by multiplying 18,405 by 74, which is incorrect. They should be using the formula: P = Sum[p*(1-p)^n,n,0,74].
By the way, don't believe all the hype about survivor II's "isolated outback location". By US or European standards, it's isolated. By Australian standards, it's actually pretty close to a reasonably large town/small city. It's less than 200 miles from a popular coastal resort!
If you really want isolation, might I suggest the Canning Stock Route.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Yea but you have to realize that the risk of a real person i.e. an American citizen, getting injured is much more remote.
I wonder what they place the odds of 1000 people getting injured at. One of those puppies deorbiting into the U.N. building while it's in session or on onto a cruise liner in the Atlantic or onto the Golden Gate at rush hour for example.
My point? These statistics are pretty meaningless, we can't halt the space program because of irrational fears. Pop tarts have killed & injured more people than space junk, as has just about any inane thing you care to mention. The merits of satelite networks easily outweigh the risks.
Okay, sure, so the chances aren't that high that anyone will be hit, but I still find it remarkable that a US company was able to do this without so much as a peep from the other countries that are put at risk. Much as I want to encourage private industry to exploit space, this kind of thing does suggest to me that perhaps we need to set up some more stringent international rules on what sorts of launches are permitted.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
There is a phenomena known as "Iridium-Flares" by which one can see the very bright sun reflections off of the iridium satellites. Go to Heavens-Above.com for predictions when you can see this from your hometown.
-Jason