Tiny Particle Blows Hole In European Satellite's Solar Panel (go.com) 225
An anonymous reader quotes a report from ABC News: A tiny piece of debris has punched a gaping hole in the solar panel of one of Europe's Earth observation satellites, causing visible damage but not enough to affect its routine operations, the European Space Agency said Wednesday. The unknown particle just a few millimeters big slammed into the back of a solar panel on Copernicus Sentinel-1A on Aug. 23. Using on-board cameras, engineers have determined that the hole is about 40 centimeters (16 inches) in diameter. The European Space Agency said the loss of power caused by the strike is "relatively small" -- less than 5 percent of the wing's usual output. The likelihood of such a strike is calculated at between 1:35 and 1:130 during the satellite's five-year lifetime, said Holger Krag, who heads the agency's space debris office. While the particle probably had a mass of less than 1 gram (0.04 ounces), scientists calculated that it was traveling at up to 40,000 kilometers an hour (24,856 mph) when it hit Sentinel-1A. Space.com has posted a video about the incident, showing images taken before and after the impact.
At last! (Score:4, Funny)
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Someone found that screw we lost in space!
But who put the screw in the Tuna?
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Why was there bacon in the soap? [youtube.com]
Unit conversion not needed (Score:5, Funny)
Using on-board cameras, engineers have determined that the hole is about 40 centimeters (16 inches) in diameter.
That's 0.00198838 furlongs for those too lazy to do the conversion.
I think slashdot readers are fine with having just the metric units. Anyone who couldn't do the conversion in their head if they cared probably isn't reading slashdot.
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Even then, I doubt that there are many people who do not have a feeling for how big 40 cm is, even in countries where inches and feet are still in use.
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Why should the US adopt the German Industrial Standards for paper sizes? We won the damn war.
You do understand what DIN means, correct?
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What? Plenty of people print in A5 at home, or for their hobby group etc. I print plenty of photographs on A5 to frame, or to send as larger postcards to friends and family.
As for making economic sense, can you fuckers in Nazi States of America fucking stop using Letter/Legal and go with A4? I'm tired of having to waste money on special binders etc just to handle paperwork from you guys. Exchange of paperwork with Taiwan? A4. Exchange of paperwork with South Africa? A4. Exchange of paperwork with Germany? A
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As soon as you fuckers pay us the billions of dollars it would cost to switch everything over, we'll talk. We invented computer printers and photocopiers after all, so rightfully you should be using our standards for paper. If you're not going to pay for the costs of converting a society of 310+M people, then fuck off. We never pushed any standards on you.
Re:Unit conversion not needed (Score:5, Insightful)
If you are going to do a unit conversion then learn about significant digits. So 0.0020 furlongs is the actual conversion for people that actually know about units and measurement.
Irony (Score:2)
If you are going to do a unit conversion then learn about significant digits.
If you are going to be pedantic then learn about irony.
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Sorry, that means nothing to me. What is it in terms of football fields?
Is that metric or imperial football?
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Which kind? (Score:2)
What is it in terms of football fields?
American Football or Association Football?
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I don't know that.
[flies up into the air]
Aaaaaaaargh!
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Anyone who couldn't do the conversion in their head if they cared probably isn't reading slashdot.
Not so sure about that. You have to take into account all of the political trolls that generate a lot (most?) of the site traffic these days.
Re:Unit conversion not needed (Score:4, Insightful)
While most are probably fine as you say. Nothing was lost by including the information and if it helped a few it was helpful.
Yes, something was lost by the conversion - the uncertainty factor changed.
40 cm in this context where the hole hasn't been accurately measured is an estimate, not a fixed value. If translating to inches, 16 inches implies a much higher precision than what's implied by 40 cm.
"14-18 inches" would be a much better conversion.
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Assuming it's to the nearest centimetre that's still less than half an inch of spread. 16 is the nearest whole number.
No idea where you pulled 14-18 from.
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Assuming it's to the nearest centimetre...
Which is an assumption you can't make when given a measurement of 40 cm, which has one significant figure (though it is somewhat ambiguous [wikipedia.org]... the ambiguity could be resolved by calling it a 0.4 or 0.40 m hole).
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Well... no. Not even the metric system could give America a real democracy.
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and the US will hold a fair election with sensible, honest, and trustworthy candidates...
Calling out just the US for this issue is pretty short sighted. Can you think of any country that has fair elections of sensible, honest and trustworthy candidates currently?
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or did you want this to be a special elite club for those who have reached metric ascendancy.
You mean everyone except America and two other shit countries? That special elite club?
One problem with a lot of computer type geeks. They seem to masturbate while fantacising about monocuulture.
So what if I know and understand more than one way to measure things? Not a brain cell wasted anywhere. Easier than learning a new language.
Because for all of the haughty pronouncements at base, the metric system is based on being 1 ten millionth of the length measured from the north pole to the equator as measured through Lyons, France.
That's just about as arbitrary a measurement (and inaccur
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This is an old argument. The thing you're missing is that unit conversion simply isn't important to most people who aren't scientists or engineers. Think about Suzy Homemaker or HR Manager Bob: why would they ever need to convert between inches, yards, or miles? Or better yet, why would they ever need to do a unit conversion involving temperature? Very few people in society ever use the Ideal Gas Law outside of Chemistry 101, and the people who do don't use Fahrenheit, or Celcius, they use Kelvins. In
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This is an old argument. The thing you're missing is that unit conversion simply isn't important to most people who aren't scientists or engineers. Think about Suzy Homemaker or HR Manager Bob: why would they ever need to convert between inches, yards, or miles? Or better yet, why would they ever need to do a unit conversion involving temperature? Very few people in society ever use the Ideal Gas Law outside of Chemistry 101, and the people who do don't use Fahrenheit, or Celcius, they use Kelvins. In short, the people who care about unit conversions are already using the SI system when they do such work, and those same people have zero trouble converting between English and metric as necessary. For everyone else, they simply don't care, and it doesn't affect their daily lives.
I think it is almost a Ford Versus Chivvy argument. Maybe allows some folks to feel superior to the fat 'murricans as well.
Even without all that, a whole lot of American stuff is done metrically now. Sometimes I wonder if part of the issue is that a lot of metalworking Machinery, which when taken care of will last a long time, is finally starting to wear down, possibly to be replaced by metric. At work, we had perfectly functional lathes that were manufactured during World War two. You have to make a pr
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Coupled with the crew who sees such things as SUV's or imperial measurements as somehow being patriotic
Those SUVs are all metric these days: all the American automakers went metric ages ago, starting in the 70s, and finishing probably in the 2000s. The construction and defense industries are probably the last big holdouts for SAE-size fasteners and linear measures.
Basically, here in the US, we're converting to metric where it makes economic and practical sense to do so. Working with SAE-size fasteners is
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Why are people arguing about *units*? The important thing is that if it had been a free-orbiting MURCAN satellite it would have had a gun with the safety off and one under the hammer and no goddam commie particle would have dared to go near it because NUMBER ONE, YAY!
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I used degrees Rankine in Thermodynamics 101, you insensitive clod.
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Metric is better for one simple reason. Forget what it's based on, everything is based on something arbitrary to other things. The reason it's better is its easy.
so is all the others. I choose to know both, and it was absolutely zero problem. It's also not being constantly revised. A kilogram is the weight of one litre of water,
The prototype Kilogram was efined in 1875 .It was found to vary in mass over time. the ICPM in 2005 reccomended that it be redefined in terms of a fundamental constant of nature. In 2011 the CPGM decided that it needed to be redefined in termes of the Plank constant. That was deferreduntil 2014, then deferred again.
And when we get into t
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If you're happy doing conversions all roads then more power to you.
whe you work with them every day, it isn't a problem.
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True. But it's much more consistent.
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True. But it's much more consistent.
True. I started to think of the standard Barleycorn as measured by some distance light travels over some amount of time. Then I decided that was probably the first step to insanity.
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The meter was originally as stated, the size to make it ten thousand kilometers from the equator to the North Pole through Lyons. After that measurement was determined, the meter became the distance between two scratches on a bar. Eventually, it and the second were determined by the speed of light in a vacuum and a very particular way of generating EM radiation.
The liter was originally supposed to be one cubic decimeter, and the kilogram was supposed to be the mass of a liter of water. They missed, an
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Yes, but if you think that's so arbitrary, remember that the yard is officially defined as 0.9144 meters.
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It's absolutely amazing (Score:3)
how much kinetic energy a spec of dust has when it's travelling over 11k m/s.
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m = 0.001 kg
v = 11,111 m/s
Ek = 61727 joules. That's 14 kilocalories, or about as much energy as in 2 ml of alcohol
Re:It's absolutely amazing (Score:5, Informative)
So, let's look at another similar energy values to help us understand how much energy the solar panel experienced (for lack of a better word).
This https://en.wikipedia.org/wiki/... [wikipedia.org] bullet (when fired) has a muzzle energy value of about half that amount. This is basically the size of round fired from a
Re:It's absolutely amazing (Score:4, Informative)
Considering that 3800 joules is the force applied by a 7.62x39 rifle bullet (i.e an AK-47 round), this is the equivalent of about 8 rounds hitting simultaneously in an area likely under a square millimeter. . .
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Considering that 3800 joules is the force
Not force, energy.
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No, 7.62x39 usually clocks in around 1.8-2.4 kj. 7.62x51 is around 3.4-4k, depending on load.
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If both objects travel at 11km/s in the same direction around the planet, they do not necessarily have any meaningful speed relative to each other. We do that whenever we dock Progress orbiters onto the ISS, and guess what, they usually don't smash into each other.
A speed alone means jack (unless close to light speed) if we don't know the reference. That Progress and the ISS both travel at the aforementioned 11km/s relative to a point on the planet below, yet relative to each other they don't move at all. I
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Mmmmm.... space bacon.....
more and more and more (Score:5, Insightful)
that space debris has created more space debris that will create more space debris that ...
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Something is going to need to be done soon about the space debris issue.
Otherwise more satellites are going to start being taken out which will created more debris, which will take out more satellites...
This issue was first recognized almost 40 years ago [wikipedia.org] and no solutions have been found yet.
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or even just a few cans of the expanding foam crack filler.
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that space debris has created more space debris that will create more space debris that ...
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that space debris has created more space debris that will create more space debris that ...
Sounds like a good movie plot.
Exponential debris spread (Score:2)
And with every tiny particle hitting a piece of space equipment, the likelihood of further collisions is increased.
I'm pretty sure there is an exponential function in this system, which is worrying. Though thanks to the vastness of space, we are still at a very low level on the progression of that function, if nothing happens at some point the function will take off and cause serious problems.
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So, a 1-5 mm piece of debris caused a hole 40cm, i.e. 400mm wide - probably creating hundreds or thousands of pieces of new debris. Since the satellite is in the crowded low earth orbit (apogee 693km [wikipedia.org]), perhaps the chance of it hitting a piece of its own solar panel in the future is probably now higher than "1:35 and 1:130", though those bits would not be traveling quite as (relatively) fast as the original impact.
Apparently this exponential debris effect is called the Kessler_syndrome [wikipedia.org]
Why the heck (Score:5, Insightful)
Re:Why the heck (Score:5, Informative)
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does it need a flash video (of all things) to show a before and after image of the panel?
Maybe they're set up to sometimes run an ad before their content? I dunno, I don't have Flash on this computer.
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No, but it absolutely DOES need the dramatic music to show two pictures.
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Why does ANYTHING need a Flash video????
It's the only way to combat Ming The Merciless
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The music made it impossible to take this seriously.
Ban all tiny particles! (Score:2, Funny)
Build a wall and make the depths of space pay for it!
!!! TRUMP 2016 !!!
Energy of 3x 50 cal bullets (Score:2, Informative)
that is about 60000J of energy, 3 times as much as 50 cal round at 20000J
Stupid conversion (Score:2)
24854.848 mph to be exact
Particle? (Score:3)
Re:Particle? (Score:5, Informative)
Aren't particles microscopic, something that can be measured in millimetres doesn't seem like it ought to be described as a particle...
In physics, yes. But they were using the general definition, which does seem somewhat out of place in this case, but is correct. This is similar to talking about a particle of dust getting into a camera lens.
speed (Score:2)
"it was traveling at up to 40,000 kilometers an hour (24,856 mph) when it hit "
How does something stay in orbit at that speed? I.m sure thats more than escape velocity.
Who said anything about orbiting? (Score:2)
How does something stay in orbit at that speed?
Who said the particle was orbiting the Earth? Or if it was orbiting it might have been a retrograde orbit so the closing velocity was the sum of the two objects.
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You're right, escape velocity at this altitude is 10.9 km/s. (https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape_velocities)
"Up to 40000km/h" is in the same ballpark, so it's hard to know for sure.
Still, 2 orbiting objects could possibly hit each other at a relative speed twice as high as the orbit velocity.
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Why is the hole so big? (Score:2, Redundant)
Serious question here is why is the hole so big?
If something is small and moving fast, would it not just go right through the panel leaving a small hole?
Or is the force so great and it 'explodes' on impact with the panel, creating the larger hole.
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Why do bullets make a small hole when entering and a large hole when exiting? When something like this hits the panel at those relative velocities, the large energies involved essentially vaporize it and some of the material it hit. That vapor (probably mostly plasma at this point) is still moving very quickly. It's essentially an explosion in the panel.
40,000 KPH (Score:2)
40,000 kilometers an hour relative to what exactly? The satellite? The earth? The sun?
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Sorry, Michael, I guess we Earth dwellers just don't have the technology your Martian foster parents had... </humor_attempt>
Actually, it's not a hole, just an "affected area" (from URL http://www.esa.int/Our_Activit... [esa.int])...
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Kinetic energy = 1/2 of mass times speed squared.
At 11 km/s, even a mote of dust kicks more than one part of human anatomy.
Re:40cm? (Score:4, Insightful)
Re:40cm? (Score:5, Informative)
When the density of the particle is high relative to the hardness of the target, there's a very high chance for penetration and low energy transfer.
But when the projectile density is relatively low compared to the target hardness, the projectle is usually deformed and stops inside the target. Or as in this case, is completely atomized, causing nearly perfect energy transfer. (approaching 100%)
So being able to ignore energy loss in the transfer make the math and modeling pretty easy. You just imagine an explosion at the point of contact, with about double the energy of the projectile. (since explosions are omnidirectional, wasting 50% of their energy in the other direction on impact, and in this case, 100% of the energy is transferred into the target)
And at orbital and escape velocities, delta-V is so high that even a very low M yields a lot of joules.
Final thing to consider, these panels aren't terribly sturdy. They're made to be extremely light, store compactly, and self-deploy/assemble in space, making them overall pretty delicate. This isn't built anything like the solar panel on your roof. It's more like the model car in your dad's display cabinet. Shoot that thing with an airsoft gun and see what happens.
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This isn't built anything like the solar panel on your roof. It's more like the model car in your dad's display cabinet. Shoot that thing with an airsoft gun and see what happens.
You mean someone's going to come out and beat your ass?
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But what's it's *relative* speed. It could be a lot higher OR lower than 11 km/s.
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I expect momentum to be transferred in the direction of the impactor, not perpendicular to that direction, chewing up structure along the way. This structure was too stiff.
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It just has a dent in it, and the dented area is still functioning (albeit somewhat less efficient). Seems to me they got it just about as good as you could realistically wish for. Or would you rather have had a hole that might have severed electrical connections?
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What you are missing is that the collision is happening at extreme hypersonic speeds. That means that when the first atoms to collide hit, they literally cannot get out of the way of the next line of atoms. (The speed of sound is basically the fastest the atoms can move to get out of the way.) So that matter hits and is stopped, and is unable to get out of the way of the rest, etc, etc. So you end up with everything smashed to incredible pressures (higher than the inside of the sun) which causes incredi
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I expect momentum to be transferred in the direction of the impactor, not perpendicular to that direction, chewing up structure along the way. This structure was too stiff.
ZOMG! It's a conspiracy, just like Bush did 9/11!
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its cold up there
Since the damaged object was a solar panel, I suspect it might have been exposed to, y'know, the sun? In which case it would not be very cold.
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its cold up there
Since the damaged object was a solar panel, I suspect it might have been exposed to, y'know, the sun? In which case it would not be very cold.
Yes yes very clever. There is this thing called "shade" that means the temperature is all over the shop during normal operation. Solar panels in space have to survive between -100 & 125 Celsius.
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Well considering most of the time they're pointing at the sun and are only in the Earth's shade for a few minutes at high orbits... most of the time, there's a pretty constant high flux on the one side and they're thin
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It could have been in a shadow when it was struck?
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Traveling 16,000 mph ... relative to what?
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When objects traveling 16000mph collide what do you expect?
If they're both going the same direction, then not much... rubbing is racing.
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Velocity relative to me doesn't count here. What was the relative velocity? It sounds like it was a collision between a satellite at orbital velocity, and an incoming particle at roughly Earth escape velocity, but without the actual vectors it tells me little about the speed of impact.
Re:40cm? (Score:4, Informative)
One half mass of the particle times the square of the velocity applies everywhere. So, given the value of 1 gram, and 40K kph, we get just a bit under 62 kilojoules. While the mass was likely less than a gram, the velocity is the primary issue.
The initial impact area is over maybe a square millimeter at best. Given the kinetic impact of relatively common events [earthlink.net], this is roughly 8 rifle bullets. So a 40 cm area is entirely expected. While the actual hole is small (as expected, it punched through) cracks would run through a small group of solar cells, rendering the affected cells useless due to transmitted shock. . .
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For a structure presumably just 1cm thick, thats a pretty nasty failure. That particle should have just breezed through.
I'd say the thickness is the problem. The forces aren't distributed in a straight line, they get spread out throughout. If you made your solar panel thinner then it might actually lose less area to a small impactor. Ideally* though, you'd use the same mass to make a much larger flexible plastic panel that was a lot thinner, and perhaps even perforated so that an impact is more likely to tear away the minimum area rather than spread the force out throughout the panel and destroy more of it.
Apparently NASA te
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https://www.quora.com/Spoiler-... [quora.com]
"Testing for NASA's helmets included dropping an 8 lb steel ball from 6 feet."
As for the micrometeoroid - let's assume it is 1g, travelling at 40000 km/h. This is 11111m/s. This means around 61kJ
For comparison, 5.56 bullet is around 4g and travels below 1000m/s. We are talking about less than 2kJ
Steel ball will reach around 4.5m/s at point of impact, which gives 36J (not kJ)
Fracture process is complicated and depends on many factors, but from what I understand it depends mor
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Consider: There are right now hundreds, maybe thousands of satellites in orbit. Have been for half a century now. 24/7 for half a century.
A piece of space debris hitting a satellite makes the news.
Now ponder the chances of this happening to an astronaut on one out of the maybe a dozen space trips for a few hours tops that happen per year.