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Subscribe to RSSWESH's Dan Billow reports on the predictions for NASA's falling satellite.
Sometime in the next few weeks, NASA expects a refrigerator-sized hunk of a satellite to fall to Earth. But will it hit someone? Not likely. NASA says there's a 1-in-3,200 chance that any pieces of the satellite will hit anyone. In fact, there's a good chance no one will see it when it falls — whenever and wherever that turns out to be.
The space agency and the military personnel who track orbital debris say NASA's six-ton Upper Atmosphere Research Satellite, or UARS, is due to re-enter the atmosphere in late September or perhaps early October. They can't yet say exactly when.
The end of the month or the beginning of next month is still "the best estimate of what we can give right now," said Air Force Maj. Michael Duncan, deputy chief for space situational awareness at the U.S. Strategic Command at California's Vandenberg Air Force Base. "There are so many factors that will affect it between now and that point in time — the atmosphere changes on a daily basis — that it's impossible to say how that's going impact this re-entry from this point in time to then."
As the bus-sized satellite's orbit descends from its current low point of about 150 miles (245 kilometers), the military's Joint Space Operations Center will refine its projections on when it will fall, all the way down to T-minus-2 hours and later. But even when the satellite makes its descent and breaks up in the atmosphere, NASA won't be confident exactly where the pieces will fall.
"We're never really confident," said Nicholas Johnson, chief scientist and program manager for NASA's Orbital Debris Program Office at Johnson Space Center. "Even at ... T-minus-2 hours, there will be a lot of uncertainty. And when I say a lot of uncertainty, we're probably talking plus or minus 10,000 kilometers. We just will not know precisely where it's going to come down until it comes down."
Long buildup to the end
NASA does know a lot about what the falling satellite will do when it falls, however, in part because they've had a lot of time to think about it.
UARS was deployed from the shuttle Discovery in 1991 to begin a fruitful $750 million mission studying the upper atmosphere and its interaction with the flux of particles from the sun. It was the first satellite to track the rise and fall of solar activity through the sun's full 11-year cycle, and it nailed down the cause and effect involving chlorofluorocarbon use and the extent of Earth's ozone hole. But in 2005, NASA determined that UARS was no longer fulfilling any scientific function that wasn't being done better by more recently launched satellites, said Paul Hertz, chief scientist for NASA's Science Mission Directorate. So the agency put it into a disposal orbit.
Unfortunately, all of the satellite's propellant was used up when the orbit was changed, so there's nothing left to control when and where the now-inert UARS will make its final, fatal plunge. "It was really not given a lot of thought, and clearly was not part of the mission plan," Johnson said.
Over the years, Johnson and his colleagues have run models indicating that the satellite would break up during atmospheric re-entry, with 26 different components surviving the descent and falling to Earth's surface. The total mass would be about half a ton, or 500 kilograms. Johnson said the biggest piece would be a part of the satellite's main structure weighing a little more than 300 pounds (150 kilograms, or about the weight of a refrigerator).
Having a refrigerator come down on you from space does not sound like a pleasant prospect, but Johnson emphasized that most space debris falls into an ocean, a desert or some other desolate place. "Throughout the entire 54 years of the Space Age, there has been no confirmed report of anybody in the world being injured or severely impacted by any re-entering debris," he said.
One of the closest calls came in 1978, when the Soviets' nuclear-powered Cosmos 954 satellite spread radioactive debris over a lightly populated area of northern Canada. The incident caused no confirmed injuries — but it did spark a political uproar in Canada, largely because of the radioactivity and the failure to provide advance warning.
NASA said there are no toxic materials aboard UARS.
Working out the risk factors
UARS is due to come down somewhere between 57 degrees north latitude and 57 degrees south, which takes in a huge swath of the globe from northern Canada to southern South America. Thus, virtually all of the planet's nearly 7 billion people could theoretically be in the debris zone, but only because of the uncertainty surrounding the time and place of UARS' fall. NASA expects that pieces of debris, including that cosmic refrigerator, would be spread out along a 500-mile-long (800-mile-long) path.
Johnson has run the numbers for the global risk assessment, taking area and population into account. "Numerically it comes out to a chance of 1-in-3,200 that any person anywhere in the world might be struck by a piece of debris," he said.
That may sound like a huge risk, compared with the chances of winning the lottery. But remember, we're talking about the chances of anyone being struck. For example, when you buy a ticket for a raffle, there's a 1-out-of-1 chance that someone is going to win. In this case, the 1-in-3,200 chance refers to the probability of any one person losing. The chance that a piece of UARS would strike any particular person — you, for example — is more like 1-out-of-20 trillion.
Here's another way of looking at it: Johnson said that an object as big as UARS descends from orbit every year or so. If his projections are correct, you can expect to hear about a person hit by debris from such an object every 3,200 years.
Seeing and touching the satellite
The skies over Fiji lit up when fragments of Russia's 138-ton Mir space station fell through the atmosphere in 2001. Will anyone see anything like that when UARS falls?
"If they're fortunately positioned, yeah, this should be quite a nice show," Johnson said. The fiery remains should be visible even during daylight. However, because authorities can't predict where the satellite will come down, there are no plans to monitor the skies — or tell skywatchers where to look. So much of Earth's area consists of open ocean, desert or wilderness that there's a good chance no one will see the descent.
"We can't raise people's expectations and tell them to go out and look in their backyard," Johnson said.
Some of the debris might not even be recognizable as parts of a satellite on the ground, but if you do come across the cosmic refrigerator or other parts of the satellite, NASA advises that you leave it alone and call the authorities. Part of the reason has to do with health and liability concerns. "You're much more likely to get a cut by some sharp edge on a piece," Johnson said.
Johnson said there are also legal guidelines governing satellite debris that falls to Earth. "It is still the property of the United States government," he said. If debris falls in the U.S., federal authorities want to take custody of the material. If it falls within the borders of another country, the government has the right to ask for its return, Johnson said.
"No, you don't have the luxury of trying to sell it on eBay," Johnson said.
Johnson recalled a case involving a nose cone from a European Ariane 5 rocket booster that washed up on a Texas beach in 2000. A beachcomber named Barney Corey reportedly ended up with the object and planned to turn it into a hot tub.
"We, however, convinced him with the help of our colleagues at the Department of Justice that that was not an option, and we did retrieve that object," Johnson said "We would do the same thing for any objects recovered in the United States from UARS."
Robert Pearlman said times were different when NASA's Skylab fell from orbit in 1979: Pieces of the space station landed harmlessly in the Australian Outback and soon ended up on the open market. Fragments were incorporated in a wide range of products, including pens and posters. "Those pieces helped educate the public and got the public interested in space," he said.
Pearlman himself recalls getting a poster from New York's Hayden Planetarium that was accompanied by a smidgen of material from Skylab. "It hung in my room for all my childhood days," he said.
As Pearlman discussed how times have changed, it sounded as if he was almost hoping a piece from UARS would fall in his backyard. Not the cosmic refrigerator, maybe, but enough of a keepsake to revive those childhood memories.
"One wonders what the authorities would say," he mused, "if you said, 'Hey, I found it. ... If you don't need it, can I keep a piece of it?"
Update for 5:45 p.m. ET Sept. 10: I initially used a comparison to lottery odds as an illustration of a situation where someone is assured of winning, but a commenter pointed out that lotteries don't necessarily guarantee a winner in a particular drawing. A better example would be a raffle, where the winning ticket is drawn out of a hat. Guess it's been a while since I've played the lottery.
More about space debris:
- Six-ton NASA satellite set to fall
- Experts sound alarm about space junk
- Russians determine cause of Soyuz crash
- Japan to go fishing for space debris
Check NASA's UARS status page for updated information about the satellite's whereabouts, all the way to the end.
Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding me to your Google+ circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.
Leave a Comment:
Unfortunately, all the propellant was used when the orbit was changed and nothing left to manuver the satellite with.... sounds like the new NASA intern had his hand on the button too long, "Hey guys, how do I turn this one off?...Ooops".
Does homeowners cover falling satellites?
My refrigerator has been acting up so I hope it lands here!
If the proper owner claims a lost item, it is never really "finder's keepers".
If you lost your car and I find it, can I keep it? Of course not.
Not to nit pick, but it is Finders Keepers on anything where there isn't a legal standard for a burden of proof. IE, a car having a title, a shipwreck being awarded to a person under maritime salvage law, etc. If something can't be traced back to you legally, and sometimes even if it can, its your word against mine that I didn't buy it from you...or that it is yours at all.
My neighbor needs a new car, so let it fall on top of it so they can file a claim and get one.
:)
Jack,
Actually I believe there is. I believe the outerspace treaty specifically indicates that all space objects are considered owned by the nation that launched them (even if privately launched) and that any salvage claims will be treated the same way as in maritime law, which basically says that only the government of that nation has the right of salvage unless they specifically revoke that. (Similar to the Bismark not being exploited like the Titanic was because it is a government owned warship and only the German government can authorize it).
The thing about touching this is that there is some really nasty chemicals used in the production of space vehicles/satellites and the last thing you want to do is to touch something and then go home and find that your hand has been eaten away because you put your hand all over hydrazine.
Jon: Interesting point, I hadn't known that until now. I just read that there is a push to change existing laws as to make "Space Salvage" a business.
Well I think the outerspace treaty needs a refresh, but I don't think that it would have mattered for this satellite as it is a government owned satellite. For a privately owned satellite (say the Iridium constellation) the rules might be up for a change.
I believe that the outerspace treaty needs to be refreshed because the environment is changing. I think we need rules as to how the moon, or other celestial bodies can be exploited for resources, which it is pretty much impossible to do right now.
Something that just occurred to me...when shuttles reenter earth's atmosphere, they reach temperatures around 3,000 degrees. The ignition temperature for every chemical / fuel I can find is in the 500 (max) - 1,200 degree range (max).
Wouldn't anything dangerous likely have already burned up?
depends on exactly where in the reentry phase the vehicle broke up and the heat dissipation characteristics are of the specific component that is breaking up.
A lot survived the Columbia reentry as an example.
It'll probably hit me, with the luck I am having lately. Hopefully it will just take me out quick, and not pin me horribly for hours or days till somebody finds me.
Not you Tony, Your bad luck will end. I am praying it hits my gossipy neighbor across the street. It will really give her something factual to talk about.
wanna talk about bad luck.. This morning I woke up with a sore neck (slept in a weird position), got work and looked down to find out I had a flat tire, took the car in to Les Schwab tires and found out my struts needed replacing, so now I'm out a couple hundred bucks and my neck still hurts and I still have so much construction in my town that my new struts will probably be leaking again next year. lol!
May all our luck change for the better. Mob, the latest storms messed with my house and car. Covered by insurance, yes, but minus $500 deductibles for each. I need a break.
Anyway, I was kidding about the satelite hitting me, just sounded funny. Rob, I agree. lets see if we find a way to control the fall and drop it where we want. lol
Tony and Rob, we all have a little list of folks we would like to see the space junk land on.
I remember when sky lab came down. I found a piece of metal on the street and took it to work. I told everyone it was part of sky lab that fell in my yard. I think some of the nincompoops believed me.
If anyone does get whacked by falling space stuff, they will be famous. Tony, you are famous enough already so it won't be you.
mob, even worse you probably did not need front struts, Les S stores loves to sell you stuff you don't need since Les S died, their ads are hooey
I vote for Dick Cheney. He deserves, more than anyone else.
If it does hit him, I wonder if his toes will curl up, like the witch in Wizard of Oz.
I'm afraid only a wooden stake or silver bullet would work on Cheney.
I have heard that he keeps his actual heart in an 'Undisclosed Location' just like any other demon in the stories...
If it hits here at night, we'll never hear it. Husband and dog both snore too loudly.
LOL
Haha! Good one.
I snore loudy too. That is hilarious essie. I'm sorry you never get any sleep. My wife feels your pain.
Interesting that things have changed so much since 1973. If it should land on your property and cause damage, will the U.S. govt. pay for the damages? I would imagine that an object the size of a refrigerator would make a heckuva crater if it landed in someone's backyard. I'm sure it would turn my Prius into a pancake!
A water landing would be cool. Hopefully it lands in someones olympic sized pool.
So why wouldn't they shoot a missile or explosive device at it right now? It makes sense if you make the pieces small enough before it starts it's descent, they will totally burn up in the atmosphere and not be a threat to anyone.
Because the missile is worth more than you and your stuff.
Sorry, but that's how our government sees the situation.
Because then it would be like a shotgun blast instead of a rifle bullet.
road ripper
because when you have an explosion up there, the fragments go off in many different directions and many of the fragments will take years, sometimes decades to reenter.
A) No hazardous materials remain on board, unlike the spy satellite shoot down of several years ago.
B) We've proven we can hit satellites in low Earth orbit, and we're pretty sure the Chinese got the message the first time...
Doug
There is still hydrazine on board, though far less than on the satellite from a few years ago, so that would be a negative to shooting it down. (the level of hydrazine might be on the order of 10% of the tanks, and it is possibly frozen right now). There are amounts of other very toxic chemicals that would be on board.
This would mostly, as you indicate in A), something that is of far less of a safety issue that would lead to the better solution being to shoot it down.
GendoIkari
I think the ISS is worth much more than your stuff, also all the GPS satellites up there, the LEO remote sensing satellites etc...
Ok, so we have 2 known factors:
1. They can determine a 1 to 3,200 chance that the object will not hit somebody.
2. They have a window-frame of late September/early October for it to enter our atmosphere.
So if you don't REALLY know when it will enter our atmosphere, you cannot conclude the odds of it hitting somebody or not.
FAIL!!!!
I'm really more worried about it hitting a whale, they're such big targets
Brett, the probability is based on it coming down anytime. Don't need to know exact time.
Right, this probability is just based on the area of the potential fall (which takes up a good portion of the globe) and the number of people in that area (pretty much the whole world's population). There may be other factors involved, but there's not enough information to come up with a probability for a particular area.
And interesting how 1-in-3,200 odds sounds good if you're buying lottery tickets, but not so much when it's the odds of something supersonic landing on your head.
I don't see how time is a relevant variable. Explain specifically how when it comes down affects the odds of an impact with a person.
It sounds as if these figures are still a bit confusing, even though it seems clear to me. For a particular person like Fallout-1986007, trying to judge the risk, the chance of being hit is 1 out of 20 trillion. If you're trying to estimate the chance that *anyone* will be hit, that would be 1 out of 3,200. This is based on NASA's figures, of course.
Suppose you had a BB gun at a carnival game booth, and you won a prize if you hit any one of a number of pennies mounted on a wall that's 100 yards away. That might be analogous to the 1-in-3,200 figure.
But now suppose you're an observer, betting that someone else will hit a particular penny mounted on that wall. Not just any penny, but your own special penny. Now you're getting into the kind of probability for a particular person to be hit by a piece of the satellite, which is analogous to the lottery odds.
The idea of one person being hit every 3,200 years is just another way to visualize the "hit any penny" scenario. If I have a 1-in-3,200 chance of hitting a penny with a BB when I take a shot, and I take a shot only every year ... then, on average, there will be 3,200 years between each time when I actually hit one of the pennies.
Hope this helps ... although I'm dubious. ;-)
I think a better analogy would be flipping a coin. If you and a friend get together and flip a coin, the odds are very immense that either one of you will win ten straight coin flips. However, if you get 1,024 people together, and pair them off in a simple NCAA-style tournament, the winner will have won ten straight flips - there's a 1:1 chance of this happening.
The odds of hitting someone depend on the population and distribution of those people around the planet. Unless there are some mass migrations in the next few months, the date when it descends doesn't change those odds.
Most of the statistics that come out of NASA really aren't all that useful to anyone but those in NASA. The one in 3200 figure is even more meaningless because there really isn't a statistical track record to base the calculations on to produce that number.
Now I am not saying that the statistics are not meaningless in general, just that you need to be an insider to understand what it really means.
Part of what makes the timing to be so 'Up In The Air', so to speak, is our atmosphere itself. It is not always a uniform height/distance from the Earth and so the densities of air that the spacecraft encounters, although minute, make a BIG difference as to when it will actually fall. In some areas air that has been heated will rise, leading to increased air column height and if something like a large Solar flare/MCE were to suddenly heat the atmosphere then for a satellite hitting that increased air pressure it would almost be like running into a wall . Since the exact warming/air column heights are constantly changing it makes it impossible to give an exact time of arrival.
does home owners insurance cover this type of accident?if it does not ,boy are you in a heap of troble.
It wouldn't matter. Under the outer space treaty, the owner nation would have to pay for any damages anyways.
If the main chunk fell on my land, I would claim salvage rights, then charge the government $100,000 for my recovery effort.
Brian
You have no salvage rights under US law.
dragon slay
Probably not, but the government would have to pay for any damages.
If they hit it with a kinetic weapon, a large amount of "buckshot" would get blasted right back into the orbital paths of a @!$%#load of other satellites.
I'm sure the Insurance company would say, "It was an Act Of God".
I've never won a thing so I'll probably be the lucky winner with this "Prize"!!
I hope a nice chunk falls on my daughters old car...maybe she will be lucky and get a new car with all the publicity, and then I am off the hook...and NO, I do not want her car hit while she is driving or sitting in it...
On second thought, maybe a huge piece could fall on Capitol Hill and knock some sense into those people?
1/3200 anybody may get hit, 1/32 billion it would do any good.
Nothing ever changes with MSN...still running same old stories, but with different titles! Who wants to read the same crap twice!
Who wants to *write* the same crap twice? At least I'm trying to write different crap...
Lowell, if you don't want to read the same crap twice then why do you read it twice? Nobody made you do it and you wasted your time all by your little self. And then you burned more of your time complaining about it. What's up with that? He, he.
Alan,
I wrote a 'crap story generator' in university if you want it. (I took the concept from a star trek plot generator which constantly generated crap star trek plots that were eerily reasonably accurate)
I could update it to include 'blame obama' in various forms.
Jonathan,
Very funny, but could you make it so it will "blame Bush" instead?
I could, it was originally a blame carter bit, but that was a while ago.
Dear Team and readers,
Do you have environmental concerns ?
As a participant of Singularity University 2011 at NASA , let me please share with you my video about space debris:
or
Thanks and feel free to share,
Jazz
Here is a troll who just registered this month and made the exact same post elsewhere.
I for one love your articles Alan. I also think it's awesome that you choose to give feedback to your readers comments. Did I see you shut down the political trolls the other day? I think I did. 3 for 3. Keep up the good work.
Thanks for the kind words, Brimania ... I do try to keep the discussion on track, but you folks can help as well by using the "!" button to flag posts that go off topic or off the deep end.
Lets have it land in the pool in Washingtom DC - A clear message that Jaysus is watching. He's burning the Bush's state now, so a a fridge sized chunk of space junk might be considered Amana from heaven.
Just a minor quibble.
You write that the odds of "someone (/anyone) winning the lottery are 1-1", which is simply not the case (well, unless we count those $1 winnings, but if we did then this wouldn't illustrate the point you're trying to make). Powerball, for example, can go multiple drawings without a winner - which is why the jackpot gets so ridiculously big.
Wow, that's a good point. I'll change the comparison to a raffle. Thanks for the truth squadding, J.Q.
Better to call it a "drawing"...apparently if you call it a raffle, any income has to be declared. Who knew?
That goes to show that the goverment owns everything and everybody
Ah, but who owns the goverment? Or did it just appear out of nothing in the big bang?
"Numerically it comes out to a chance of 1-in-3,200 that any person anywhere in the world might be struck by a piece of debris," he said.
Since the earth is over 70% water them ain't good odds folks.
Rummy, the fact that so much of the Earth's surface is water is one reason behind the 1-in-3200 chance (or actually, 1-in-20 trillion for a particular individual, as noted above).
Owwwwwwww.... That hurt!
I still think the odds of it hitting Dick Cheney are slightly higher because he is made of pure evil.
If it landed in North Korea, would they consider it an act of war?
No. It would be considered an offering to Kim Jong Il.
NASA needs to set up a program to clean up all the debris people have left in orbit. It's dangerous up there.
It will also be a bit embarassing if we ever have extraterrestrial vistors. "So sorry, the maid hasn't been..."
(This is meant to be a response to comment #24, not sure why it posted here.)
So just how hard will this refrigerator-sized chunk hit? At what speed will it hit the ground (or water)? Are we talking smashing a car flat, or an obliterating crater?
The article is confusing. In one sentence it says, refrigerator size; in another, bus-size.
I don't think this may result in all Dinosaurs becoming extinct. :o)
I believe the satellite is currently "bus-sized" but "refrigerator-sized" chunks (parts broken up during re-entry) of it could hit someone, somewhere.