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back to article Space-junk RAYGUN wins Australian government funding

A proposal to use lasers to clean up space junk is a step closer to reality, courtesy of $AUD20 million of Australian government funding. Led by EOS Space Systems (based at Australia's Mount Stromlo, home of one of the country's major observatories), the collaborators will start small, developing lasers that are able to identify …

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Makes sense

I get the lasers, every situation needs them.

What I don't get is how they are going to get sharks into LEO or how they will control them (Mechjeb?)

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Re: Makes sense

Nonsense, real sharks can shoot down space junk while swimming in the sea. SSSL = Surface to Space Sharkey Lazor.

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Joke

Re: Makes sense

Look up "Hi no tori 2772" (aka "Phoenix 2772"). Take a good look at the spaceship. Any more questions...?

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Dual use...

If these lasers can pour enough light to slow down space junk at 300 km., they probably are also able to blind an enemy drone's cameras, or an enemy pilot.

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About bloody time...

...that somebody actually does something about space junk.

Personally, I would like to have an international co-operation that agrees to de-orbit or otherwise eliminate anything in orbit that is not registered. So, a piece of space junk, be it defunct TV satellite or non-registered spy satellite, would be tracked, the orbital and any other obtainable data posted for six months at a central registry site, and if nobody claims the object within that time, get it the hell outta there.

We (mankind) have been able to shoot garbage into space for far less than a century, yet there is an incredible amount of stuff up there that serves absolutely no purpose, but makes it more and more hazardous to place anything else in Earth orbit, and that "anything" includes humans.

Come to think of it, I figure it would also be fair that the companies or organisations that put the junk up there in the first place be billed for its removal. They could have planned and engineered for de-orbiting or otherwise removing their scrap metal once it became such, after all, but obviously didn't, leaving it to others to clean up after them.

Maverick thought here: there are a lot of very valuable resources in various Earth orbits. Rare Earth metals, gold, other precious materials which have already been refined to usability so would be relatively easy to recycle at a much lower cost than that of originally refining them. I wonder whether it would become feasible, once the various private space ventures manage to get an affordable ground-to-orbit transport together, to "mine" disused satellites?

Just an idea.

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Re: About bloody time...

There are two types of space junk: Big (satellites) and small (nuts, bolts, fleck of paint, spanners, etc).

I suspect this laser tech is intended for the small stuff.

Larger junk is gonna be a different kettle of fish. I believe newer satellites are now designed to have thrusters & fuel to either de-orbit them or push them into a very high (i.e. out of the way) orbit.

As to "mining" defunct satellites, I suspect it'll be a long time before that becomes commercially viable. Look at the practicalities: You have to launch a large vehicle, get it to the satellite, remove appendages that were never designed to retract (e.g. solar panels), bring it into the launch vehicle, then bring it all back down to Earth. (And you have to do all of that without creating any new debris too!) Only then, can you look to process the scrap. That's a lot of money & tech for scrap metal.

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Happy

Re: About bloody time...

Sounds like Salvage 1...

http://en.wikipedia.org/wiki/Salvage_1

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Re: About bloody time...

The mining refers to reusing mass and remanufacturing on orbit.

Bringing it back down serves little benefit.

However with launch costs as they are 3-4 tons of aluminium, steel, copper, gold, silicon, [insert other material used] is worth at least $65-90m on orbit in launch costs alone.

Yes processing the material is currently not possible, but there is time.

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Re: About bloody time...

"It's a beautification campaign."

"I dare say you need it!"

"Space junk. Straker thinks the aliens could use it somehow to breach our defence systems."

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Happy

Re: About bloody time...@annodomini2

Exactly what I was thinking there; thank you for clarifying where I failed to do so in my original comment. Have an upvote :)

@Graham Marsden: I had not been aware of that series, but yup, that's the general idea! (and, of course, also have an upvote for pointing out the Prior Art here :P )

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We need to place a solar powered satellite that does this automatically. It locks onto a target, asks permission, then de orbits it. It's the "ask permission" part that might be the rub. There should be an allowed response time and if that time is exceeded it should automatically retry the request and if it doesn't receive a reply from the junks owner a committee should decide if the junk should be removed.

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Spacecraft expecting a response from someone...

What could possibly go wrong?

cf Star Trek 1, 4, etc.

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Why lasers?

Second law of Newton. Controlling the orbit of the cleaner satellite will be loads and loads of fun.

Excuse me for being stupid, why lasers instead of an Archimedes mirror? A 64 segment mirror can exert 30+ the pressure of a laser while not being affected by range. A 128 segment mirror will vaporise the target outright. Sun angular diameter is 0.5 degrees so the "spread" of an archimedes mirror is comparable with most lasers. You do not need to zap that piece of junk at any time by order of supreme cheef of staff so the fact that a mirror needs to be a in a "good" position relative to the sun to be effective is irrelevant. In fact, if your job is to clean junk there is always a nice selection of targets to whack relative to the mirror. Apply the same number of whacks while "ahead" of the sun and while "lagging" it and you are in the same orbit. And so on.

Most importanly - we can build it now. All it takes is a set of precise actuators, an unfolding mirror structure, a targeting radar and some software. In fact the software (keeping the damn thing in a proper orbit) is probably the most difficult part of the lot.

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Re: Why lasers?

Number of moving parts.

A space based laser would only need 1 for the solar cells, everything else would be done by moving the whole satellite. If they're using solar navigation (i.e. solar sails) then they may not even need fuel to change orbital location.

Weight

Mirrors aren't any where near as light as the laser would be.

Cost

Linked to the 2 above.

Hardiness

Given that it's going to be trying to shoot space debris, a laser that can be protected/armoured to some extent is going to be easier to protect and make rugged than a collection of mirrors that need to be able to move around to focus sunlight at a specific spot.

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Re: Why lasers?

"why lasers instead of an Archimedes mirror? "

Maybe because a laser can punch through the atmosphere more easily and cheaply than some humongous mirror that someone will have to go out and clean regularly.

I see nothing in the article or the announcement that says anything about space-based lasers. They are talking about the equivalent pressure of sunlight for 5 to 10 minutes to apply a nudge.

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Re: Why lasers?

"I see nothing in the article or the announcement that says anything about space-based lasers. "

And it doesn't seem to you that a ground based laser is simply going to move debris up a tiny and not very useful amount, rather than down?

The alternative is to try and slow the debris so that gravity does its business in a more convenient time frame, but that's even more challenging from the ground because you'd be firing the laser through a far longer atmospheric path.

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Orbital Mechanics- what goes up must come down

With a bit of help from the atmosphere it's very easy to deorbit something by nudging it upwards, relative to Earth. Because you aren't adding any extra orbital speed, the upwards nudge makes its orbit more eccentric so that the lowest part of its orbit is now proportionally closer to Earth. Do this enough and the orbital trajectory will intersect the upper atmosphere which will do the deorbiting for you.

Also, you don't have to shoot the laser straight up, you could shoot it towards the object as it approaches a point above the laser, that way part of the force acting on it is perpendicular to the junk's orbit and it will slow down and drop to a lower orbit. However, there's a limit to how far you can angle the laser away from vertical as you'll have to shoot through more of the atmosphere which will absorb, deflect and distort the beam more.

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Re: Orbital Mechanics- what goes up must come down

Nahh... the gap between LEO (minimum 160Km) and the highest levels of atmosphere (mesopause ~80Km) is a minimum of 80Km, so you'd need a really eccentric orbit, so not only would you create a rapidly accelerating object, you'd have it going up and down through many different orbits, creating a much more dangerous object.

Deorbiting using an eccentric orbit is a really bad idea (even it if were possible).

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Re: Why lasers?

Why lasers instead of mirrors? They are as different as night and day, that's why. Basically you need to be able to see what you are tracking/nudging from the ground. If you use mirrors you need sunlight which means the sky is blue and much brighter than the object you want to track. You can use a laser at night when the sky is black and you can actually see the object.

p.s. I've been to Mt Stromlo and seen one of their earlier satellite-tracking lasers in action: it was a thin faint green line extending towards the stars. This was before the big fire, so they might have a different setup now.

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I think someone...

has been watching Gravity.

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Joke

Re: I think someone...

You can watch gravity? Prey tell how? Do you use gravitized sunglasses?

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Trollface

Re: I think someone...

"You can watch gravity? Prey tell how?" - Easily, by following the Failarmy Youtube channel. Gravity is prominently featured in almost every single clip they have...!

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Re: I think someone...

Do you use gravitized sunglasses?

Only if I drop them from my desk. It's easy to watch gravity, and feel it. Just hold that big rock a few feet above your foot and then let go of it.

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Re: I think someone...

"You can watch gravity?"

No, you can watch Gravity. A subtle difference, but a difference nonetheless.

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Windows

Secondary Waste Disposal Consultants

I have a vision of future news reports about some city somewhere not getting satellite coverage for navigation as a bunch of blokes in the equivalent of a half-dead Transit pickup (white - it has to be white) have buggered off with some 'scrap'.

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Kudos

Congrats on reporting this story accurately, and not translating it into "scientist to use lasers to blow up space debris!" article that mainstream journalists have...

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Re: Kudos

tbh the title was somewhat sensationalist (which is of course only right and proper for El Reg).

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