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Tiny Particle Blows Hole In European Satellite's Solar Panel (go.com)
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.
Someone found that screw we lost in space!
Slashdot, fix the reply notifications... You won't get away with it...
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.
how much kinetic energy a spec of dust has when it's travelling over 11k m/s.
Have you ever fallen asleep at the keybhanusdiog?
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...)...
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.
that space debris has created more space debris that will create more space debris that ...
When objects traveling 16000mph collide what do you expect?
Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.
Everyone knows that the projectile has a large amount of energy. The question is how much of the energy was transferred to the solar panels. When a projectile blows through a thin object, most of the energy remains with the projectile.
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.
http://michaelsmith.id.au
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, 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. . .
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.
does it need a flash video (of all things) to show a before and after image of the panel?
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
Would their helmet be able to absorb the impact?
Wow...another Space Nutter shot down. The hits just keep on coming!
Build a wall and make the depths of space pay for it!
!!! TRUMP 2016 !!!
At orbital velocities the projectile is vaporized. Don't imagine a bullet, imagine a small explosion.
That event created few hundred pieces of few millimeters in size, whirling around...
that is about 60000J of energy, 3 times as much as 50 cal round at 20000J
Both objects were likely traveling in excess of 16000mph (approx 9 times the speed of a bullet). We only know which direction the impactee was traveling. As for the impactor we do not know it's mass and have only vague information as to it's volume (We know it's less than 6cm wide because otherwise it would be trackable by radar). So please explain why what is effectively a pane of glass struck by an object of unknown proportions should have suffered less damage!
Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.
24854.848 mph to be exact
Aren't particles microscopic, something that can be measured in millimetres doesn't seem like it ought to be described as a particle...
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.
I work for the Department of Redundancy Department.
Link to article containing images of damage.
Skip the Space.com video, they're just trying to force more ads on you via video.
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.
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 tested some of this stuff in space back in 2014. I didn't catch how it turned out.
* (maybe)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
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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Really makes me wonder what sort of shielding would suffice on a space ship capable of any decent sort of speed. If you're traveling very fast in one direction and you hit a few grains of dust traveling very fast in the other direction that's one hell of a lot of energy colliding.
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.
As a modelist myself DON'T shoot the (expensive and time-consuming to build) model car in your dad display cabinet, you will avoid a world of pain :-)
Religion: The greatest weapon of mass destruction of all time
"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.
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.
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.
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 incredible heat (vaporizing an approximately equal amount of impactor and impactee). Then that cloud of super-heated gas interacts with the stuff around it for a very short time.
while (sig==sig) sig=!sig;
Traveling 16,000 mph ... relative to what?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
What is it in terms of football fields?
American Football or Association Football?
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.
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
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
But what's it's *relative* speed. It could be a lot higher OR lower than 11 km/s.
There are two types of people in the world: Those who crave closure
It could have been in a shadow when it was struck?
There are two types of people in the world: Those who crave closure
No big deal to ding the solar panel of an unmanned satellite. But what about a hit on a pressurized section of the ISS or any other manned craft? The amount of roadside trash left by our satellites and launch vehicles is a well known increasing problem. (With some prohibitively-expensive solutions proposed.) It would seem that mankind didn't learn the kindergarten lesson "if you get it out to play with, put it up when you finish!"
"scientists calculated that it was traveling at up to 40,000 kilometers an hour (24,856 mph) when it hit Sentinel-1A."
40,000 kilometers an hour relative to what exactly? The satellite? The earth? The sun?
Show me on the 1st Amendment bobblehead where the moderator touched you...
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?
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Let's see.... environmental monitoring satellite, measuring ice coverage and sea levels.....
When objects traveling 16000mph collide what do you expect?
If they're both going the same direction, then not much... rubbing is racing.
It must have been something you assimilated. . . .
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!
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.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
There was one funny post about the lost screw comng back.
The other *hundreds* of posts were idiotic flame wars about measurement units and what not.
A more interesting discussion would be to wonder how incidents like this, which per the article are common, would impact the longevity of the space station and other proposed long-term dwellings in orbit.
Just wondering.