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Broadband Expansion Could Trigger Dangerous Surge In Space Junk (theguardian.com)
A new study from the University of Southampton warns that expanding broadband networks via launching "mega constellations" of thousands of communications satellites could increase catastrophic crashes of dangerous space junk in Earth's orbit. "Dr Hugh Lewis, a senior lecturer in aerospace engineering at the University of Southampton, ran a 200-year simulation to assess the possible consequences of such a rise in orbital traffic," reports The Guardian. "He found it could create a 50% increase in the number of catastrophic collisions between satellites." From the report: Such crashes would probably lead to a further increase in the amount of space junk in orbit, he said, leading to the possibility of further collisions and potential damage to the services the satellites were intended to provide. The European Space Agency, which funded Lewis's research, is calling for the satellites planned for orbital mega-constellations to be able to move to low altitudes once their missions are over so they burn up in Earth's atmosphere. They must also be able discharge all batteries, fuel tanks and pressure tanks to prevent explosions that would scatter debris. Lewis is presenting his research this week at the European conference on space debris at the ESA's center in Darmsadt, Germany. Krag said he expected some of the companies planning launches to attend.
A "low-cost" device sent into LEO? So it's being sold on the admittedly astonishingly low cost compared to traditional launch costs.
So any additional costs (such as end-of-life mechanisms designed to put it into a burn trajectory) are going to have a proportionally greater impact on that "low cost" selling point, which means the proponents have a motive to resist such extra mechanisms and costs.
Anything sold on its main benefit being "low cost" will eventually result in a race to the bottom, and the cost-cutting that entails - "hey, our module is lighter and cheaper to get into orbit (because we decided to do without expensive impact shielding/temperature control/whatever)"
They sentenced me to twenty years of boredom
A simple solution would be for such satellites to be restricted to orbits with a short expected lifetime.
What we're really finding out here is that we need to build an orbital cleanup satellite.
We don't even need a satellite. We can do it from the earth's surface. Just put a big fricken laser on the summit of Mauna Kea or Cerro Toco, point it westward, and shoot it at the leading surface of the debris to slow it down into an unstable orbit.
Ah OK, so when the thing is worn-out and obsolete you propose to...recycle it somewhere, like on the ISS?
You know that one person-day of work in LEO costs MINIMUM 7.5 million bucks, right?
https://en.wikipedia.org/wiki/...
That buys you a fuckton of cubesats & launches, space cadet.
"Just put a big fricken laser on the summit of Mauna Kea..."
If the Democrat volcano gods hate astronomy, they are really not going to like this idea.
High orbit sats are indeed high lag. Low orbit sat constellations aren't quite so bad and have the advantage of automatically re-entering the atmosphere after a few years, rendering the professors fears of "Not being able to reliably perform an end of life manoeuvre" moot.
Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue
Where do you propose to find the Delta V to safely recover all these sats, hmmm?
They're not a couple escaped helium ballons from for birthday trapped on your ceiling waiting to be grabbed, they're flying about faster than bullets in differing and often completely opposing orbits and there is no Neo from the Matrix around to wave his hand and make them all magically stop for you.
Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue
Scientists need to invent a space vacuum cleaner.....
I think we need to teach that orbit is a condition, not a place.
Now I know it's a *horror* for your standard capitalist these days, but what about, like, PLANNING (omfg, he's said the *P* word!) a bit ahead?
How do you propose to "plan"? We don't have any use for recycled materials in orbit. There's a lot of infrastructure that would need to be in place first before it makes sense to recycle.
Think about some standards which would make those things as recyclable as possible (like trying to keep a set of agreed-upon materials, standards for easy deconstructibility -- all things which, you know, *might* help us down here too), working towards a LEO factory of the future?
Let us note that those sorts of recycling standards routinely create a big mess on Earth, including lower quality electronics (such as tin whiskers) and more effort spent recycling than would be saved in materials. I don't see the point of having expensive satellites follow some recycling standard that isn't justified, lowers the effective lifespan of the satellite, and won't actually be useful for decades until someone gets around to putting the necessary recycling infrastructure in space (by the time they do, they probably will be able to handle most of the current satellites and large space debris aside from nuclear reactors).
Unlikely. Launch capability is quite a step from ORBITAL launch capability. We have had solid-fuel rockets (gunpowder based) since the 13th century. We didn't get to liquid fueled rockets until 1926. From there to the first manmade objects to reach space were German V2 rockets during world war 2 - twenty years later. It took another twenty years for Sputnik 1 to become the first manmade object to actually get into orbit (and it only stayed there a few months). The oldest object in space is Vanguard 1 which was the first truly high-orbit satelite launched in 1964.
The sputnik 1 level tech couldn't do much serious harm - it just wasn't high enough (it's apoaps was over 900km but it's periapse was barely out of atmo). The satelites you want to harm are a lot higher up - and you want to maximize collisions so you want to blow up your bag of dirt and nails near them - in a circular orbit for maximum intersects. Indeed hitting anything in space on purpose seriously hard - but sending a bunch of random junk flying around hoping to hit some satellites may be feasible.
But to get from V2 to Sputnik1 and Explorer/Vanguard era satelites in 20 years - took many of the best minds in physics, chemistry and engineering in the world - which the US and Russia had at the time. North Korea does not have many such minds - their oppressive system and academic control also greatly reduces their ability to produce good scientists, their weak economy harms their manufacturing capacity...
And sputnik and vanguard had payloads of a few kilograms - to do real damage you want to take a LOT of junk - so at least a few tonnes. So you need a launch vehicle at least on par with later model Soviet R7's or the US's Mercury or Saturn Launch Vehicles.
Right now - North Korea has only once managed to put something into orbit. They claim a polar orbit with a period of 94 minutes - if we believe them that would mean they can just about put a small satellite where Sputnik 1 had it's periapsis. And they cannot do that reliably - North Korean rockets have tended to fail more often than succeed.
So could this conceivably happen ? Sure, but it seems unlikely - for the same advances that you need to achieve this, you could build highly effective ICBMS which make great propaganda television - and this, I think, is why NK has been focusing on the latter (which they don't seem likely to actually achieve any time soon).
Unicode killed the ASCII-art *
O'rly
http://www.space.com/27128-dar...
There you go satellites that repair other satellites go figure.
Obligatory " I for one welcome our orbiting robotic overlords"
Yeah, geosynchronous satellites are way out there at about 6 Earth radii with 700ms ping times.
We're talking about all of the new low earth orbit mesh networks, though, that SpaceX and Facebook and Google and Virgin Atlantic have all expressed interest in launching, either as part of the Iridium 2 constellation or in competition with it.
Here's a visualization I've made of SpaceX's proposed 4000+ node constellation based on mission parameters that Elon Musk has announced publicly:
https://youtu.be/neLPRMrhy80
Imagine trying to clear a comfortable launch window through that!
Not sure if he's really serious about it, or if it's just a bargaining chip to get better negotiations for the Iridium 2 launches. But the factory for these things is just down the road across town, so I suppose I could go check.
The suit that stopped construction was brought by native Hawaiians who feel that their state was stolen by the white man and a federal judge gave them enough credence to stop construction. Feel free to attempt to buy off one or the other. I wish I could be there to see the consequences...
Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue