Author Topic: Cleaning up near earth space  (Read 34771 times)

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Cleaning up near earth space
« on: 02/22/2009 06:51 PM »
Hello everyone

I'm new here

Would like to know,

Is there a discussion on spacejunk here?
What is the latest on efforts to clean up our space?

As an interesting starting point,
it cost a fortune to get whatever it is up there, Why not start collecting that junk, build a barge like container with this junk and then collect more junk in this container and start reprocessing it into usefull building material for further space work.

My ideas would be in the line of a magnettic winch such as used in scrap metal processing that could collet the stuff up there.
Robotic equipment that could process the materials or just package it and send it off to where it would be usefull.

Why mess with lazers to destroy it?

   

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #1 on: 02/22/2009 06:58 PM »
It's not practical.  Yes, it costs a lot to get things into space.  But once they stop working, they are worth nothing at all.  It's not like gold or platinum.  So there is no reason to collect it.

Also, understand that in order to collect the junk, you have to launch an expensive mission.  And there are tens of thousands of pieces of junk, most of them way too small to track reliably or even detect.  And they are all in different orbits and different velocities, so gathering them up is like running through a flock of chickens and trying to grab them one by one.

The only realistic policy is to try and reduce the amount of junk that is produced from each launch.  There are many ways to do this, including forcing spacecraft to reenter at the end of their lifetimes.  The most effective strategy is to reduce the possibility that your spacecraft will generate debris during launch.  For instance, batteries can explode when exposed to repeated heating and cooling.  And fuel tanks that have some fuel left in them can also explode.  So you design these systems so that they don't explode.

However, right now those are voluntary measures.  There is no international agreement or effort to reduce debris generation.  After the satellite collision, expect people to start talking about international agreements to address this issue.
« Last Edit: 02/22/2009 06:59 PM by Blackstar »

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4417
  • Liked: 189
  • Likes Given: 382
Re: Cleaning up near earth space
« Reply #2 on: 02/22/2009 07:23 PM »
In some common orbits it might be worthwhile to collect the junk for processing.
Other less common orbits some means to deorbit the trash is needed.
Cleaning up GSO for example would be fairly easy delta V wise if you gather the dead sats in once place in GSO for processing or send them to the moon.

LEO tethers can be used for orbit changes and to deorbit items using little to no propellant.

Small stuff a laser would be the best route or a VASIMR engine's exhaust could be used to deorbit small debris.

Making LEO sats and upper stages carry a terminator tether or retro pack would help a lot in reducing debris.
Using a reusable SEP tug in place of an upper stage when possible also would reduce debris.
« Last Edit: 02/22/2009 07:28 PM by Patchouli »

Offline nomadd22

  • Full Member
  • *
  • Posts: 170
  • Liked: 2
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #3 on: 02/22/2009 07:34 PM »
 The reason the Iridium collision was so unbelievable is that there are a hundred smaller object capable of taking out a satellite for every complete bird, so cleaning up old sats wouldn't really do much good. Between the sat the idiot Chinese military destroyed and all the debris from intentionally blown up Russian sats there are hundreds of thousands of pieces of tiny debris that can kill a satellite at those velocities.
 In other words, cleaning up the debris enough to make a difference would cost thousands of times as much as the satellites you would save.

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #4 on: 02/22/2009 07:51 PM »
Blackstar, I do agree with you in that what has stopped working is now of no value, BUT, if anything should take the life of an astonaught or even disable or disrupt any working satilite then WE have to make every effort to prevent it from destroying object in its path.

And while there is no active and workable project at present, let us for a little while examine what we have and can do.

Organic matter I see no way of controlling if it has been released into space allready, however, I can imagine some young rookie working on hubble and having his visor splattered with a turd, enough to put a damper on any mission.

metalic object do however carry some horrible risk of making anyones life a misary and with a simple magnet floating around just ready to collect metalic stuff into a ball would be very helpfull.

a tea-strainer would come in handy for small non-metalic object thereby we can start with a shuttle, after completion of a mission, to do an orbit or two with the express instruction of getting a problimatic area of debris under control. I'm not even asking them to bring it back,just collect it,and send it into an orbit where it could be picked up for sorting and re-use where posible......

Hey I also want to build me space port..... with the junk up there,this is not going to be easy. 

Patchouli, yes you are talking the way I'm thinking.....What we can do, lets do it. What we cant, well, lets keep thinkin of some way to do something about it.

Nomadd22, cleaning up debriss might cost much more than anything up there at present, but, What is the cost of a life?
mmmm..... I think we better start cleaning up....and have a plan to get the launchers to send the debris they create with each launch to a central place where it will not harm anyone or anything....

Yes, let everyone limmit the debris going up but what cannot be elliminated should be controlled.


Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #5 on: 02/22/2009 08:05 PM »
There are some concepts to deorbit small pieces of space debris using a ground-based laser.

See for example this paper.

Advances in solid state laser technology should make such a system relatively cheap. But building such a system would be a huge political issue since it would also be able to interfere with active satellites.

I guess people will only act after a really expensive orbital asset is lost to space debris.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline Bubbinski

Re: Cleaning up near earth space
« Reply #6 on: 02/22/2009 08:18 PM »
I'm not sure how you would even begin to deorbit all the junk that's up there.  Debris travels in different orbits and at different altitudes with different sizes and space is a pretty big place.  You'd have to make a really, really large "debris sweeper" (magnet or aerogel?) to try to collect it, it sounds impractical.  At least right now.  In 100 years who knows?

Besides not creating the debris in the first place, spacecraft could be "hardened" to survive impacts.  The ISS has covers over windows and shields over the module structures and CBM's for this purpose.  I suppose more hardening would at least be discussed if earth orbit got "riskier", things like shields over sensitive parts, beefier structures, that kind of thing, though there is a mass and cost penalty.
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6691
  • Liked: 1000
  • Likes Given: 140
Re: Cleaning up near earth space
« Reply #7 on: 02/22/2009 08:26 PM »
metalic object do however carry some horrible risk of making anyones life a misary and with a simple magnet floating around just ready to collect metalic stuff into a ball would be very helpfull.

a tea-strainer would come in handy for small non-metalic object
...

There's an important aspect to this you seem to be missing.  The closure rate on most of this stuff, regardless of what orbit your collection system is in, will often be several times faster than the speed of the fastest rifle bullets.  Even getting a magnet or "tea-strainer" in the way is difficult, but if you do, you're far more likely to create more space junk than you are to reduce it.

Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17812
  • Westphal, Nova Scotia
  • Liked: 464
  • Likes Given: 4605
Re: Cleaning up near earth space
« Reply #8 on: 02/22/2009 08:32 PM »
I'm not sure how you would even begin to deorbit all the junk that's up there.  Debris travels in different orbits and at different altitudes with different sizes and space is a pretty big place.  You'd have to make a really, really large "debris sweeper" (magnet or aerogel?) to try to collect it, it sounds impractical.  At least right now.  In 100 years who knows?

Besides not creating the debris in the first place, spacecraft could be "hardened" to survive impacts.  The ISS has covers over windows and shields over the module structures and CBM's for this purpose.  I suppose more hardening would at least be discussed if earth orbit got "riskier", things like shields over sensitive parts, beefier structures, that kind of thing, though there is a mass and cost penalty.

A long time ago in a post far far away, I had suggested aerogel with a containment skin. Magnets are practically useless. Think about it, mass is your #1 driving factor, so are you going to launch a steel item, or something made of Aluminum or Titanium? Magnets only work for certain metals, specifically ferritic ones. You might catch some meteorioids, some stainless items, but overall you'd have better luck with a giant carbon-kevlar honeycomb filled with aerogel. If they could deploy such a large beast, there' a starting point.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #9 on: 02/22/2009 08:33 PM »
BUT, if anything should take the life of an astonaught or even disable or disrupt any working satilite then WE have to make every effort to prevent it from destroying object in its path.

How much money do you think we should spend for what percentage of risk reduction to an astronaut's life?  Should we spend $1 billion to reduce the risk by 1%?  If so, who should pay for that?  The United States?  Russia?  China?

I vote for the Brazilians.  It's about time they started pulling their weight for a change...

Offline Jorge

  • Senior Member
  • *****
  • Posts: 6182
  • Liked: 35
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #10 on: 02/22/2009 09:00 PM »
In some common orbits it might be worthwhile to collect the junk for processing.
Other less common orbits some means to deorbit the trash is needed.
Cleaning up GSO for example would be fairly easy delta V wise if you gather the dead sats in once place in GSO for processing or send them to the moon.

GSO is the *only* such "common orbit". With all other orbits, the delta-V requirements are far too high.

(and the very fact that makes the delta-V requirements for GSO cleanup so low - low relative velocity between the birds - also makes the problem less urgent.)
« Last Edit: 02/22/2009 09:01 PM by Jorge »
JRF

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #11 on: 02/22/2009 09:14 PM »

How much money do you think we should spend for what percentage of risk reduction to an astronaut's life? 


What is the cost of doing an orbit or two more with the shuttle, let them deploy a gel-net on one mission, pick it up,wrap it and, well, whatever they then decide to do with it is better than leaving it as individual little missiles.

But, ok, what solutions do we have coming forward so far..... Lazer? ok, do it.... lets get started....we want 1 - 20 cm objects out of the way.... who has a project running for this?....  what is the develpement status for it?...

Who should pay? ..... um.....who put it there in the first place?..... let them start taking the responsability for it....  and ok....who wants to use space to go play in.....start a lottery if you cannot get anything better, main prize = a tour of the spaceshuttle and the hanger.....

Cost can be covered, somehow, but, cleaning up must start taking a prioprity or does it not bother anyone that "my son or daughter" is going to have to duck&dive bits&pieces that we pushed up there? 

If for $10 000 a gell ball can be placed in the way of 10 pieces of matter per month, ok, so its going to take a long time. Start now and in a few years we will have it under control. Start in ten years time....its just going to take longer.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #12 on: 02/22/2009 09:18 PM »

What is the cost of doing an orbit or two more with the shuttle, let them deploy a gel-net on one mission, pick it up,wrap it and, well, whatever they then decide to do with it is better than leaving it as individual little missiles.



100s of millions.  And the gel-net may not capture anything.
There is no easy solution to this.  LEO can not be effectively cleaned up by another spacecraft.  Too many different orbits and too large of volume.

Proof: Look at the ISS, it has a large surface area.  Most of its impacts are from micrometeoroids and not space junk

The solution is not to generate more and harden the vehicles against the current debris
« Last Edit: 02/22/2009 09:24 PM by Jim »

Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17812
  • Westphal, Nova Scotia
  • Liked: 464
  • Likes Given: 4605
Re: Cleaning up near earth space
« Reply #13 on: 02/22/2009 09:25 PM »
Nobody's going to pay for it if they're sent a bill, plain and simple. Same reasoning, some would say, as it it applies to cleaning up the environment of greenhouse gases.

$10,000 would never do it. Try $2B easily for development (shot in the dark), and at $1,000 /kg, you would be talking about at least a 5000kg unit, and several of them at that. This also assumes you don't have a failure and cause more debris going up, it can happen.

How I see it, is that those who fear or understand the costs of LOM/LOC for shuttle/ISS, or a satellite failure causing financial loss, would be willing to add to a fund to reduce that risk. The good thing about Polar orbit debris removal is that you can set up a partial array to help 'defend' you territory directly overhead. For LEO, you can only hope for a sort of defense shield for the ISS, and possibly for a crewed vehicle going there, but again the costs of that would be prohibited. It's a big sky up there.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #14 on: 02/23/2009 12:10 AM »
Who should pay? ..... um.....who put it there in the first place?.....

I don't know.  Who do you think put it there in the first place?

Look up the catalog of objects that are currently in orbit, all 30,000+ of them, and list the owners for all of them.  Then post that list to this thread.  Remember, if you're not part of the solution, you're part of the problem!

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #15 on: 02/23/2009 12:22 AM »
Yeah, yeah, I'm being flip, or snarky, or fliply snarky...

But you need to realize that it is nowhere near as easy as you may think.  There are tens of thousands of pieces of stuff up there, all flying around in different orbits and at different velocities.  There is no practical way--none at all--to clean up even a tiny amount of that stuff.  Even talk about lasers to push the stuff around is just goofy--idle chatter by people who have not bothered to work out things like how much power it would take to do this.

The only viable solution is to work hard to reduce the amount of debris that is produced on new launches.  And to try and get other countries to agree to do the same.  And you learn to live with the threat as it exists.  That's the only thing that works.
« Last Edit: 02/23/2009 12:23 AM by Blackstar »

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6691
  • Liked: 1000
  • Likes Given: 140
Re: Cleaning up near earth space
« Reply #16 on: 02/23/2009 12:36 AM »
Even talk about lasers to push the stuff around is just goofy--idle chatter by people who have not bothered to work out things like how much power it would take to do this.

Now, wait a second here, people including NASA have worked on this for the huge numbers of small objects (single-digit centimeters or less) out there, and it seems to be only challenging, not impossible.  Yes, it's virtually impossible for spent stages and damaged satellites with substantial mass, but not for the small, but still deadly small items that dominate the shear numbers of objects out there.

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #17 on: 02/23/2009 01:17 AM »
Really?  What will it cost?  And how much improvement will it provide?

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6691
  • Liked: 1000
  • Likes Given: 140
Re: Cleaning up near earth space
« Reply #18 on: 02/23/2009 01:20 AM »
Really?  What will it cost?  And how much improvement will it provide?

They claim they can deorbit these small items on a single pass.  How much investment in equipment would be required is probably not well known, but it would be significant I'm sure.

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #19 on: 02/23/2009 07:37 AM »
Hello all

Blackstar you are correct, you are entitled to voice your concerns, and everything you say is being thought of carefully. Here we might banter, moan, begrudge, well anything but we are trying to get ideas together, clear the sky, make space a safer world, and if even one thought we bring forward gets picked up by someone that can do something, well, I rate that as success.

What have we at present......

Gell-net, cloud, grapling arm, reduce debris being deposited, lazer, mmm..... what else, yes, cost is prohibative, yes, sending accounts to all and sunder is not going to work, but hey, talk, dream, fantasize, vebalize, caution, whatever .....

Do we all agree,
there is a problem?
does it warent us addressing it?
can something be done about it?
can we prevent it from growing bigger?

Am I allowed to learn something while debating a topic I know dangerously little about?

How I'd love to lay my hands on the new shuttle sim, I'm sure to learn a lot about space and the various bits&pieces that go into getting us up there.

I'm not upset or angry, I hope I have not angered anyone with this discusion, let us talk while talk is available to us.

Later
Regards

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #20 on: 02/23/2009 08:22 AM »
Even talk about lasers to push the stuff around is just goofy--idle chatter by people who have not bothered to work out things like how much power it would take to do this.

Sorry, but I have to disagree with this. The paper I linked is definitely more than idle chatter. There are more detailed proposals, but for the sake of the discussion I linked to one that is freely available on the internet.

They specifically discuss power requirements and costs. They only propose to deal with the debris in the 1..10cm range.

The technology exists to focus laser light on objects several 100km away. It is not cheap since you need an aperture of several meters, but it is definitely possible if you are willing to spend significant amounts of money. As an example, see the Boeing YAL-1 Airborne Laser.

A space debris mitigation facility would probably cost on the order of a billion USD. But that is less than the cost of a single large earth observation satellite, which kind of puts the cost in perspective.
« Last Edit: 02/23/2009 08:26 AM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9910
  • Lansing MI
  • Liked: 252
  • Likes Given: 31
Re: Cleaning up near earth space
« Reply #21 on: 02/23/2009 08:36 AM »
I highly recommend reading some of the literature and signing up for the quarterly newsletter at the NASA Orbital Debris Program Office for those with more interest...

http://orbitaldebris.jsc.nasa.gov/

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #22 on: 02/23/2009 09:37 AM »
Thanks Rdale
Very interesting.
I'll be looking at that site often.

Offline cozmicray

  • Full Member
  • *
  • Posts: 166
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #23 on: 02/23/2009 05:22 PM »
The vastness of space  -- look at the volume between the top of
the atmosphere out to Geosync orbit and about 18000 objects.
About 6.4 trillion Cubic Miles per object in orbit
Lots of space between pieces of space junk!!!

Hard to grasp a cubic mile  let alone 6.4 trillion!!!

Offline DMeader

  • Full Member
  • ****
  • Posts: 956
  • Liked: 100
  • Likes Given: 47
Re: Cleaning up near earth space
« Reply #24 on: 02/23/2009 05:30 PM »
The vastness of space  -- look at the volume between the top of
the atmosphere out to Geosync orbit and about 18000 objects.
About 6.4 trillion Cubic Miles per object in orbit
Lots of space between pieces of space junk!!!

Hard to grasp a cubic mile  let alone 6.4 trillion!!!

If I may quote the late Douglas Adams....

Quote
"Space is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."

From "The Hitchhiker's Guide to The Galaxy"

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #25 on: 02/23/2009 08:30 PM »
Am I allowed to learn something while debating a topic I know dangerously little about?

You sure are.  But your posts reflect an attitude that is actually rather common among space enthusiasts.  Because you see a problem, and don't see a solution, you are assuming that people who work in the field are obviously not trying hard enough, or not being inventive enough, or are simply not smart enough.  Because, if they were, they would have solved the problem.  Obviously, something is wrong with them.  (See: ISS construction and resupply, Ares I)

But as is frequently the case, the new person, the outsider, has very limited knowledge of just how tough a problem it is, and even less understanding of how much effort has already been devoted to it.  So if you really want to learn, a better method is not to keep proposing your own solutions on a bulletin board, but to start by reading some books and learning about the physics and the previous efforts to address it.  There are a number of books on the topic.  And quite a few journal articles.  I went to Amazon and typed in "orbital debris" and came across a number of hits:

http://www.amazon.com/s/ref=nb_ss_gw?url=search-alias%3Dstripbooks&field-keywords=orbital+debris&x=0&y=0
« Last Edit: 02/23/2009 08:35 PM by Blackstar »

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #26 on: 02/23/2009 08:33 PM »
Sorry, but I have to disagree with this. The paper I linked is definitely more than idle chatter.

What was the size of their research grant to study the issue?  How big was the research team?  Did their proposal go beyond Phase A?  How much has been spent developing the technology?

I measure the seriousness of a proposal in part by the amount of money spent on development.  This proposal has never been studied in detail or evaluated for technical, political and budgetary feasibility.

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #27 on: 02/24/2009 05:23 AM »

You sure are.  But your posts reflect an attitude that is actually rather common among space enthusiasts.  Because you see a problem, and don't see a solution,
Very true.

you are assuming that people who work in the field are obviously not trying hard enough, or not being inventive enough, or are simply not smart enough.  Because, if they were, they would have solved the problem.  Obviously, something is wrong with them.  (See: ISS construction and resupply, Ares I)
Not true....I do realize there are many much more knowledgable than myself, however, how often has a solution come from new, stupid, uninformed ideas being thrown into the pot?



But as is frequently the case, the new person, the outsider, has very limited knowledge of just how tough a problem it is, and even less understanding of how much effort has already been devoted to it.  So if you really want to learn, a better method is not to keep proposing your own solutions on a bulletin board, but to start by reading some books and learning about the physics and the previous efforts to address it.  There are a number of books on the topic.  And quite a few journal articles.  I went to Amazon and typed in "orbital debris" and came across a number of hits:

http://www.amazon.com/s/ref=nb_ss_gw?url=search-alias%3Dstripbooks&field-keywords=orbital+debris&x=0&y=0

Thanks, will look into it, this is a real good starting point.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #28 on: 02/24/2009 11:37 AM »

Not true....I do realize there are many much more knowledgable than myself, however, how often has a solution come from new, stupid, uninformed ideas being thrown into the pot?


Not very often

Offline William Barton

  • Senior Member
  • *****
  • Posts: 3487
  • Liked: 2
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #29 on: 02/24/2009 11:54 AM »
One comment about this subject, with regard to cost effectiveness: Jet airliners still ingest birds and fall out of the sky. It's a solvable problem, but no one wants to pay for a solution.

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #30 on: 02/24/2009 12:12 PM »
Sorry, but I have to disagree with this. The paper I linked is definitely more than idle chatter.

What was the size of their research grant to study the issue?  How big was the research team?  Did their proposal go beyond Phase A?  How much has been spent developing the technology?

I measure the seriousness of a proposal in part by the amount of money spent on development.  This proposal has never been studied in detail or evaluated for technical, political and budgetary feasibility.

So you are arguing that the amount of funding a concept receives is an indicator of the feasibility of the concept? While this is probably often the case, there are also various counterexamples in both directions.


Various extremely technically challenging concepts such as NASP and the lockheed x-33 have received significant funds, while other much simpler concepts such as Transhab and the other x-33 proposals have not received significant funding.

DIRECT has received precisely zero funding, while ARES has received several billion USD. Does that mean that ARES is infinitely more feasible than DIRECT?


Seriously, I think even if deorbiting space debris with a large ground-based laser was completely technically feasible, I can think of many political reasons why the concept is difficult to sell.

Can you specify which part of the orion laser proposal you think is too difficult?

a) Spotting the space debris
b) focusing a laser on it from ~1000km away, or
c) deflecting it by evaporating a thin layer?
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #31 on: 02/24/2009 06:31 PM »
One comment about this subject, with regard to cost effectiveness: Jet airliners still ingest birds and fall out of the sky. It's a solvable problem, but no one wants to pay for a solution.

Kill all the birds.

Offline ApolloStarbuck

  • Member
  • Posts: 62
  • NC
  • Liked: 22
  • Likes Given: 3
Re: Cleaning up near earth space
« Reply #32 on: 02/25/2009 09:04 AM »
Left on their own, debris will deorbit evenutally with no effort on our part.  The problem is when the debris starts impacting other debris and making even more, harder to track fragments.  at some point LEO becomes a swarm of small, destructive kinetic missiles.

Could a large orbiting mirror be used, concentrating light pressure on swaths of certain orbits and deccelerating small particles enought to cause them to deorbit?
Of course, I suppose that would also interfere with any satellites in the same orbit.

Just a thought.
...weren't we supposed to be on Mars by now?

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #33 on: 02/25/2009 07:13 PM »
Could a large orbiting mirror be used, concentrating light pressure on swaths of certain orbits and deccelerating small particles enought to cause them to deorbit?

I guess large enough mirror will eliminate more junk by colliding with it than by zapping it with lasers.

Thus, make it even bigger, but you don't need it to be a mirror :) Imagine something to the tune of 100x100 meter flying square which destroys debris by colliding with it.

Will still take a lot of time (or a lot of squares) to measurably clean up LEO.

Offline Prospero

  • Member
  • Posts: 31
  • Hampshire, UK
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #34 on: 02/27/2009 11:54 PM »
Just wondering - would there be any scientific benefit to getting some of the older/deceased satellites out of orbit and brought back to Earth somehow for disassembly, even if they have orbits that will remain stable for decades more anyway? To see what things worked well/badly and what types of things could be learned from this to put in to new systems etc to improve their ability to function in some way? I'm not talking about the how & how much to do so at this stage, just whether or not it would be of use. Not being in the industry of Satellites etc I don't know whether this kind of thing would actually be of any benefit even if it was simply a case of clicking your fingers and the bird in question were on the table ready to be carved up so to speak ;)

Also, do any of you think it would be worthwhile for some of these things to be brought back and put in museums? I know for example that I would pay to go see a museum of these things, showing our efforts in space over the years - even just historical items like the glove that escaped the Gemini pod on one mission etc?

With regard to the general question of clearing up space junk/debris though, I do feel that we should take a more responsible attitude to what's currently up there. While it is laudable and indeed essential that we do our best to ensure that future missions etc minimise adding to this debris field, I don't think we should just wash our hands of the rest of it just because it seems too expensive an issue to fix so to speak. It's mankind's backyard after all, and if we made a mess then we should really think about clearing it up if it's at all possible - maybe discussion in to possible solutions to this should therefore be encouraged rather than dismissed/supressed? Ok - the stats might indeed show that the chances of any of this stuff actually causing harm to anything up there are small, but a chance is still a chance, and surely a smaller likelihood is something to be aimed at just for the sake of those improved odds of not having something cause an issue?

Mark
"Floodlit in the hazy distance
The star of this unearthly show
Venting vapours, like the breath
Of a sleeping white dragon"

RUSH - Countdown

Offline Vacuum.Head

  • Full Member
  • *
  • Posts: 154
  • Still in the Cradle
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #35 on: 02/28/2009 01:24 AM »
Not very often

But when they do they revolutionise their scientific field.
Here's one: E=mc^2. Remember he was working as a patent clerk at the time: http://www.independent.ie/entertainment/tv-radio/einstein-and-eddington-1549477.html. The first paragraph gives a good summary as to how his peer group reacted....
And just to add insult to injury:
"All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein's "Wonderful Year". At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright. Some of this work—such as the theory of light quanta—remained controversial for years.[28][29]"
Wikipedia
Unfortunately we will always have the "Utter Bilgers" with us:
http://en.wikipedia.org/wiki/Richard_van_der_Riet_Woolley
In my experience it is only when the old guard die off, that real scientific progress can be made! If there is one thing that behooves us as speculative thinkers, scientists and engineers working at the boundaries of the possible is that sometimes we should listen to the right brain and look for ideas coming from the <a href="http://www.phrases.org.uk/bulletin_board/16/messages/609.html" >left field[/url]!
http://en.wikipedia.org/wiki/Clarke%27s_laws
----------------------------------------
"...all the Universe or nothing." Oswald Cabal
["Shape of Things to Come" U.K. 1936  (Dir. William Cameron Menzies)]

Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17812
  • Westphal, Nova Scotia
  • Liked: 464
  • Likes Given: 4605
Re: Cleaning up near earth space
« Reply #36 on: 02/28/2009 02:43 PM »
Just wondering - would there be any scientific benefit to getting some of the older/deceased satellites out of orbit and brought back to Earth somehow for disassembly, even if they have orbits that will remain stable for decades more anyway? To see what things worked well/badly and what types of things could be learned from this to put in to new systems etc to improve their ability to function in some way? I'm not talking about the how & how much to do so at this stage, just whether or not it would be of use. Not being in the industry of Satellites etc I don't know whether this kind of thing would actually be of any benefit even if it was simply a case of clicking your fingers and the bird in question were on the table ready to be carved up so to speak ;)

Also, do any of you think it would be worthwhile for some of these things to be brought back and put in museums? I know for example that I would pay to go see a museum of these things, showing our efforts in space over the years - even just historical items like the glove that escaped the Gemini pod on one mission etc?

With regard to the general question of clearing up space junk/debris though, I do feel that we should take a more responsible attitude to what's currently up there. While it is laudable and indeed essential that we do our best to ensure that future missions etc minimise adding to this debris field, I don't think we should just wash our hands of the rest of it just because it seems too expensive an issue to fix so to speak. It's mankind's backyard after all, and if we made a mess then we should really think about clearing it up if it's at all possible - maybe discussion in to possible solutions to this should therefore be encouraged rather than dismissed/supressed? Ok - the stats might indeed show that the chances of any of this stuff actually causing harm to anything up there are small, but a chance is still a chance, and surely a smaller likelihood is something to be aimed at just for the sake of those improved odds of not having something cause an issue?

Mark

Mark,

I'm sure a case could be made to have the satellites as museum pieces, but the costs involved would be prohibitive. Anything more that a couple million and the response would be "let it burn'.

From a implementation point of view, if you made a hollow CaRV that opened up, with a heat shield & parachute for re-entry, that would be the way to go I think. Alot of small detail in there would be required for stationkeeping, to fit it properly, and make it secure.

As for failure modes, the ISS provides that platform for us just fine. Anytime something fails is a gold mine imo: lessons learned. The mmod shielding and solar arrays are also getting bombarded regularly, so that's direct evidence & scientific data to go by. Too expensive to return a satellite for that purpose alone, although the recent failure of that military satellite (second failure, with more in that series ready to launch, which they halted pending review). There might be a case for that if no root cause were found.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #37 on: 02/28/2009 06:40 PM »
Just wondering - would there be any scientific benefit to getting some of the older/deceased satellites out of orbit and brought back to Earth somehow for disassembly, even if they have orbits that will remain stable for decades more anyway? To see what things worked well/badly and what types of things could be learned from this to put in to new systems etc to improve their ability to function in some way?

Considering how much it costs - no. You can do the same research on ISS or a dedicated materials research satellite. There were at least two such satellites launched and retrieved by Shuttle.

Quote
Do any of you think it would be worthwhile for some of these things to be brought back and put in museums?

Not on my tax dollars please.

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #38 on: 02/28/2009 06:44 PM »
Not very often
But when they do they revolutionise their scientific field.
Here's one: E=mc^2. Remember he was working as a patent clerk at the time: http://www.independent.ie/entertainment/tv-radio/einstein-and-eddington-1549477.html. The first paragraph gives a good summary as to how his peer group reacted....
And just to add insult to injury:
"All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein's "Wonderful Year". At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright.

You make a false assumption that since Einstein was right but was ridiculed by some at first, every insane idea is actually brilliant, but misunderstood.

I'm afraid that for every Einstein, there are millions of idiots, and almost each has his own insane ideas.

Offline mmeijeri

  • Senior Member
  • *****
  • Posts: 7457
  • Martijn Meijering
  • NL
  • Liked: 76
  • Likes Given: 185
Re: Cleaning up near earth space
« Reply #39 on: 02/28/2009 06:56 PM »
Here's one: E=mc^2.

Speaking of which: what would happen if we nuked some of the debris? Not seriously suggesting that of course. Would that vaporise the debris or send extra shards all over the place? My guess is that instead of dangerous debris you would now have radioactive dangerous debris. The EMP would likely also be ... unhelpful.
We will be vic-toooooo-ri-ous!!!

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9910
  • Lansing MI
  • Liked: 252
  • Likes Given: 31
Re: Cleaning up near earth space
« Reply #40 on: 02/28/2009 07:02 PM »
Any kind of nuclear explosion in space would create massive communications and electrical blackouts for a wide radius.

And you still only impacted a SMALL area of space.

Offline DMeader

  • Full Member
  • ****
  • Posts: 956
  • Liked: 100
  • Likes Given: 47
Re: Cleaning up near earth space
« Reply #41 on: 02/28/2009 07:20 PM »

Speaking of which: what would happen if we nuked some of the debris? Not seriously suggesting that of course. Would that vaporise the debris or send extra shards all over the place? My guess is that instead of dangerous debris you would now have radioactive dangerous debris. The EMP would likely also be ... unhelpful.

Bad idea. Bad, bad, bad.  Go Google "Operation Starfish" for info on when something similar was actually tried back in the early sixties, and imagine what the consequences would be to the computerized, power-gridded, satellite-based level of technology we have now.

Offline mmeijeri

  • Senior Member
  • *****
  • Posts: 7457
  • Martijn Meijering
  • NL
  • Liked: 76
  • Likes Given: 185
Re: Cleaning up near earth space
« Reply #42 on: 02/28/2009 07:29 PM »
OK guys, I know this is a bad idea and I did mention the EMP. But I'm genuinely curious what the effect of a nuclear explosion on a very dilute plasma would be. Would you still get a shock wave? And would stuff vaporise or shatter? My guess is that some shards would be generated at some distance from the explosion.

Googling a bit, I found something curious. It looks as if a nuclear explosion high in the atmosphere causes the atmosphere to 'heave'. And the US military at one point seriously considered this as a defense against Soviet missiles, because their course would be altered by the heave. I kid you not.
We will be vic-toooooo-ri-ous!!!

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #43 on: 02/28/2009 08:20 PM »
Some ideas coming through, yes, on the surface they seem not the best, but, lets for one moment dwell on the nuke idea....(Yes, Gospacex, I agree this is a bad idea.)

maybe vaporize some debris, but, alter the trajectory of others?
Do we not consider getting the debris to re-enter earths atmosphere?

museums?....  mmmm .... a museum on the moon?

A big mirror?   ....  how about a big blanket that even if the debris should hit and go through, would it not slow the debris down and thereby deorbit it? oh......blanket? yes, cloth or gel or whatever....just something that can hold or at least slow the speeds the debris is travelling at.

Einstein having a rough time getting his idea accepted..... how many other ideas not even showing a single spark of interest?....yes, um.... popular saying " to find a prince you got to kiss a lot of frogs"

ok.....we getting a few ideas coming in....disregarding cost for the moment, time needed to get control of the situation, lets look at what could work and what does more harm than good?

A question that I've been asking myself, is there any point in space, lets say an area of some 5 km square that over a , what?, a year, would have a large amount of the debris passing through it?   maybe even two or ten such places? or is all the debris spread out so much that we would only get the odd hit? 

« Last Edit: 02/28/2009 08:24 PM by DrCoffee »

Offline Vacuum.Head

  • Full Member
  • *
  • Posts: 154
  • Still in the Cradle
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #44 on: 03/01/2009 01:26 AM »
You make a false assumption that since Einstein was right but was ridiculed by some at first, every insane idea is actually brilliant, but misunderstood.

I'm afraid that for every Einstein, there are millions of idiots, and almost each has his own insane ideas.
Talking about false assumptions... ;D
but let it pass... let it pass!
I never ass_u_me anything except that every insane idea *may* actually be brilliant but totally misunderstood by everyone else.
But that it *is* safe to assume that there will always be some neophobe/ luddite/ idiot who will not and cannot accept any new idea insane or otherwise.

Quote
“Rail travel at high speed is not possible because passengers, unable to breathe, would die of asphyxia.”
Dr Dionysys Larder (1793-1859), professor of Natural Philosophy and Astronomy, University College London.
I was looking for the above and found a goldmine!
http://www.thefastlanetomillions.com/off-topic-discussion/4750-30-quotes-all-proven-wrong.html Enjoy!
To return to the topic:
With the exception of some particularly dirty orbits which might be susceptible to a demonstration of the Orion System.
Discussion:
http://www.spacefuture.com/archive/orions_laser_hunting_space_debris.shtml
Abstract:
http://cat.inist.fr/?aModele=afficheN&cpsidt=3109525

Like Death and Taxes micro-particulate debris is something we will just have to live with and, anyway, there is little we can do about the micro-meteors.
In the short term we'll just have to take our chances with the bigger stuff  but its commercial value, even as scrap, can be enhanced with a little imaginative thinking...
Bring on the TOAST (Tele-Operated/ Autonomic Super Tug)
Edit: to sneak in a Hyperlink.
« Last Edit: 03/01/2009 12:42 PM by Vacuum.Head »
----------------------------------------
"...all the Universe or nothing." Oswald Cabal
["Shape of Things to Come" U.K. 1936  (Dir. William Cameron Menzies)]

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 12985
    • Space Launch Report
  • Liked: 4084
  • Likes Given: 769
Re: Cleaning up near earth space
« Reply #45 on: 03/02/2009 04:24 AM »
it cost a fortune to get whatever it is up there, Why not start collecting that junk, build a barge like container with this junk and then collect more junk in this container and start reprocessing it into usefull building material for further space work.


Space Shuttle itself has demonstrated how objects can be retrieved from orbit.  Palapa B2 and Westar 6 were recovered after kick motor failures, refurbished, and relaunched.  LDEF was recovered and brought back to Earth.  Solar Max and LEASAT 3 were repaired in orbit, turning "space junk" into working assets.  Hubble Space Telescope has of course been repaired in orbit several times.  Several smaller free-flyers were released and recovered, again removing potential "junk" from orbit.

The technology has been demonstrated.  Someone has to pay for it, or something like it, of course.  That's what it will boil down to at some point.  When the junk problem grows tough enough, the checkbooks will have to open.  The cost of a satellite mission will then include launch, on-orbit operations, and deorbit disposal or recovery.  Our satellite TV bills will have to bump up a bit, etc.

 - Ed Kyle   
« Last Edit: 03/02/2009 04:25 AM by edkyle99 »

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #46 on: 03/02/2009 04:55 AM »
Ok - could buy off on a orbital "deorbit tug" that could conceivably anchor a deorbit package on a dead sat, and that eventually you might get it to lower perigee to where it would enter atmosphere - but that would be a hell of a system to design, test, build, and deploy. Even worse to fund.

But with the shards of a satellite - nope. Vaporizing with a laser is nonsense - issues of optics diffraction, target absorption, specular reflection, heat capacity ... all make this a difficult weapon to build.

At least with current laser weaponry, all you want is to disable something, not necessarily the science fiction "instant vaporization" of a hundred ton launch vehicle and payload. C'mon - get real!

The problem with fragments is that its easy to make more fragments from them. You want the reverse - to collect them up into a cost effective pile and deorbit that - a very dubious proposition.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #47 on: 03/02/2009 07:36 AM »
Vaporizing with a laser is nonsense - issues of optics diffraction, target absorption, specular reflection, heat capacity ... all make this a difficult weapon to build.

Can you quantify why this is nonsense instead of just listing a few buzzwords?

Focusing laser light from the ground to satellites and vice versa over a distance of 1000km is routinely done with laser communications terminals.

Quote
At least with current laser weaponry, all you want is to disable something, not necessarily the science fiction "instant vaporization" of a hundred ton launch vehicle and payload. C'mon - get real!

Nobody is talking about evaporating whole launch vehicles. You just want to illuminate a tiny (1-10cm) particle of space debris and evaporate a thin layer of material to create a force on the particle.

If you wanted to evaporate an entire piece of space debris, that would indeed be impossible. But nobody is proposing this, so this is just a strawman argument.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #48 on: 03/02/2009 11:06 AM »
Something that seems to keep getting lost is how much volume we are talking about.  Think that we are talking about altitudes of about 400 km to about 1600 km ALL OVER THE EARTH.  So a 1200 km blanket over the entire planet.  That's a tremendous amount of volume to clean up.  And using lasers requires a tremendous amount of power.

Offline DonEsteban

  • Member
  • Posts: 67
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #49 on: 03/02/2009 12:35 PM »
Something that seems to keep getting lost is how much volume we are talking about.  Think that we are talking about altitudes of about 400 km to about 1600 km ALL OVER THE EARTH.  So a 1200 km blanket over the entire planet.  That's a tremendous amount of volume to clean up.  And using lasers requires a tremendous amount of power.
The fact that the volume is so huge is a big argument FOR lasers.

The Orion cited above claims something like 10MW CW laser, or 30kw for pulae laser. Even that 10MW is not "tremendous" at all.


Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #50 on: 03/02/2009 12:54 PM »
Something that seems to keep getting lost is how much volume we are talking about.  Think that we are talking about altitudes of about 400 km to about 1600 km ALL OVER THE EARTH.  So a 1200 km blanket over the entire planet.  That's a tremendous amount of volume to clean up.  And using lasers requires a tremendous amount of power.

The volume would be a problem for a "orbiting flyswatter" approach, but it is not a problem for a stationary laser. If you put a laser facility at a location with good seeing like for example hawaii, almost every single piece of space debris would fly over it at some point in time.

The only pieces you would miss would be the ones with a lower inclination orbit than your location. Since most low earth orbit space debris was launched from florida or baikonur, that would not be much.


The total mass of small (1-10cm) space debris is probably not that big. Maybe a few tons. And the laser does not have to evaporate it all, just decelerate it by a few 100m/s so that it deorbits.


And fortunately power is quite cheap on the ground. Powering a 30kW pulsed solid state laser like the one mentioned in the orion paper might use a megawatt of grid power (3% efficiency), but so what?


It might well be that deorbiting small space debris with a ground-based laser is completely impractical. But so far nobody has given a convincing argument why that might be the case.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #51 on: 03/02/2009 07:37 PM »
it cost a fortune to get whatever it is up there, Why not start collecting that junk, build a barge like container with this junk and then collect more junk in this container and start reprocessing it into usefull building material for further space work.

Space Shuttle itself has demonstrated how objects can be retrieved from orbit.  Palapa B2 and Westar 6 were recovered after kick motor failures, refurbished, and relaunched.

How many times more did it cost compared to just building and launching a replacement?

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #52 on: 03/02/2009 08:31 PM »
The fact that the volume is so huge is a big argument FOR lasers.

Really?  What is the attenuation rate for a laser at 400 km altitude, and 1600 km altitude?
« Last Edit: 03/02/2009 08:32 PM by Blackstar »

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #53 on: 03/02/2009 08:53 PM »
The fact that the volume is so huge is a big argument FOR lasers.

Really?  What is the attenuation rate for a laser at 400 km altitude, and 1600 km altitude?

Given a sufficiently large aperture, the same. You only get significant attenuation in the atmosphere. The attenuation depends very much on the angle of the laser relative to the vertical. A laser fired almost horizontally would be attenuated very much. Firing straight up would be best for attenuation, but that would be useless for decelerating the debris.

In any case, the attenuation is not the real problem since it is only a few percent. The biggest problem is that the refraction index of the air varies over space and time, so the ray gets diverted in a random direction by a tiny amount. The same effect is responsible for the "flickering" of stars.

You can avoid this to a large degree by choosing a site with good seeing, and compensate for the remaining fluctuations by using adaptive optics. This is almost exactly the same technology used by large ground-based optical telescopes.

Note that I am not really an expert for this. But I do know that the attenuation in vacuum is zero and thus not really the problem.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Online Blackstar

  • Veteran
  • Senior Member
  • *****
  • Posts: 11430
  • Liked: 2962
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #54 on: 03/02/2009 10:00 PM »
Given a sufficiently large aperture, the same.

Sorry.  Sloppy wording on my part.

What is the beam spread and therefore the power delivered at those different altitudes?

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #55 on: 03/02/2009 10:13 PM »
Well, since you asked so nicely  :D
I am just curious why this won't work. Thanks for the detailed reply.

1. There are diffraction limits to the optics used to convey the beam - note that the diameter of the optics/beam grows as the distance to the object. Perhaps you've heard about pinhole or slit diffraction pattern - realize that it works the same in reverse.

I am aware of the diffraction limit. You would indeed need a sender aperture of meters. In the orion paper they mention 6m diameter. Not cheap, but certainly doable.

Quote
To shoot a hundred miles (smallest LEO straight up) we are talking meters, and even then we have atmospheric turbulence that would require adaptive optics to surmount.

Atmospheric turbulence might be the biggest problem. When building a receiving station for a satellite-based laser, the deflection happens at the end of the ~400km where it does relatively little damage, while when sending the laser the deflection happens at the start of the path where it does the most damage.

But the airborne laser project also needs to solve this problem to get a significant fraction of the laser energy on target. And for a short (ns) laser pulse at least the deflection does not change over the pulse time.

Quote
Even after that, to convey enough power to vaporize any metal in orbit, you would have to have a power product at the surface that would be so high that you would be ionizing atmosphere, making it impossible to do the AO, let alone that a fraction of the beam would be incident on the target (e.g. say edge on), so you would need considerably longer time to expose the target.

But if your target is ~10cm diameter, and your sender aperture is several meters, then the power product at the sender would be much lower. And close to the target where the power product is highest there is no atmosphere to worry about.

Quote
If you don't have a brief enough pulse, you just cook it and most of your energy departs as black body radiation - the amount going in/out is set by the absorptivity/emissivity of the target, and the heat capacity before solid to liquid, liquid to vapor phases is set by the specific heat of the substance, all of which are very different for substances of glass, silicon (found in solar panels), aluminum (bus), aluminum oxide (electronics) ... etc.

The paper mentioned 30kW for a pulsed laser with nanosecond pulse length and megawatts for a continuous laser. So you need a pulsed laser.

Quote
Another issue is the direction of the vector of force - if you shoot vertically (for the shortest path mentioned above) then you're not going to optimally apply the resultant deltaV (you are perpendicular), while if you fire at a grazing angle for max delta V reduction, you are not only shooting a much long path (by 10x!), you are shooting thru a larger length of atmosphere.

So you will probably shoot at the flattest angle you can get away with.  Even if it is just 45 degrees, that gives you a large target volume. 

Quote
Now I can take these down a few more levels, but I don't care to do a dissertation on laser weaponry in a post. Perhaps you might want to do a little work on your own, in particular look at the effectiveness of YAG lasers used in manufacturing, to get some idea of what is required at 10mm distance to vaporize metal, then apply this to meters or kilometers, to get an idea of the issues involved.

Correct me if I am wrong, but given a sufficiently large aperture the distance should not matter. What matters is how big the focus area is. If the focus area is 10000 times bigger (10cm*10cm) you need 10000 times as much power as a tabletop industrial laser focusing on 1mm^2. This won't be cheap, but certainly doable.
« Last Edit: 03/02/2009 10:17 PM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #56 on: 03/02/2009 11:00 PM »
Given a sufficiently large aperture, the same.

Sorry.  Sloppy wording on my part.

What is the beam spread and therefore the power delivered at those different altitudes?

If you focus a 1000nm infrared beam to a distance of 1000km using a 6m diameter mirror, you get a spot size of about 2*1.22*lambda*R/r=0.407m according to wikipedia.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #57 on: 03/03/2009 07:13 AM »
Good. It's also like the Airy disk of a telescope, but you also have to remember that you *can't focus* on the target - it's effectively at
infinity.

If this is true then that pretty much kills the whole idea. Your spot size at the target would be about the same area as the mirror area (slightly larger because of the diffraction limit), and you would need an absurdly powerful laser to evaporate anything at all.

But I am not sure why it should not be possible to focus on a fixed distance like, say, 1000km with a large mirror. I am aware that the beam at the focus will have a non-zero diameter because of the diffraction limit.

Some back of the envelope calculations for a 6m mirror give a diameter of about 0.4m, which would still give a ~225 times higher flux density than at the sender.

Quote
Trust me, it affects ALL laser weapons, and it's a very major deal. Try asking the ABL guys about it.

I agree that atmospheric turbulence is probably the biggest problem of the concept.

But since the ABL guys seem confident that they can get a significant fraction of their beam on an ICBM 300-600km away, it must be solvable.

They are also using an infrared laser, and a very powerful adaptive optics system (from the FAS page on the project: The mirror has 341 actuators that change at a rate of about a 1,000 per second.)

Quote
Quote
But if your target is ~10cm diameter, and your sender aperture is several meters, then the power product at the sender would be much lower. And close to the target where the power product is highest there is no atmosphere to worry about.

You know about the inverse square law right? Well trust me the flux density is fantastically higher on the ground than in orbit.

The inverse square law does not apply here.

flux density(sender)*beam area(sender)=flux density(target)*beam area(target)

So if it is possible to ensure that the beam is thinner at the target than at the sender, the flux density will also be higher. If this is not possible, the whole project would be impossible with current laser technology.

Quote
Perhaps you don't understand me - to vaporize you still have to add this energy - the shorter the pulse, the more the energy. 30KW in a nanosecond pulse won't vaporize enough - with diffraction, atmospheric losses, and target coupling losses this is dubious.

Sorry. I quoted the 30kW number from the paper. A power figure is not very meaningful for a pulsed laser. I assume that they mean an average beam power of 30kW. During the pulse the power would be much, much higher.

If each pulse lasts 1ns and you have 1000 pulses per second, each pulse would have an energy of 30J and a power of 30GW.

Quote
You need to shoot "edge on" - which means no atmosphere.

You just need to shoot so that a part of the momentum vector is parallel to the orbital velocity. Edge on would be perfect, but if you shoot with 45 degrees there already is 1/sqrt(2) of your momentum parallel to orbital velocity.

Obviously there is some optimum angle where the momentum transfer parallel to the orbital velocity vector is maximized.
« Last Edit: 03/03/2009 07:16 AM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline MKremer

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 3911
  • Liked: 13
  • Likes Given: 513
Re: Cleaning up near earth space
« Reply #58 on: 03/04/2009 03:04 AM »
MMOD risk is one subject I don't read about being covered nearly enough from space elevator proponents. An elevator is a sitting duck, unable to avoid anything (a thin sitting duck, but one nonetheless).

Anyway, my totally pie-in-the-sky idea uses a very thick, massive Orion-class baseplate disk (the nuclear bomb-type Orion design), but much larger. It would be angled 45º to nadir in a polar orbit (start low, then spiral out very, very, very slowly). Any remaining debris not vaporized immediately on impact would deflect and lose lots of energy into a much lower orbit or ballistic reentry.

Only downside is it's going to clean out *everything* that can't maneuver itself out of the way in time. And, as is easy to see, isn't something that would be practical or cost-effective for a long, long time.

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #59 on: 03/04/2009 01:47 PM »
MMOD risk is one subject I don't read about being covered nearly enough from space elevator proponents. An elevator is a sitting duck, unable to avoid anything (a thin sitting duck, but one nonetheless).

Anyway, my totally pie-in-the-sky idea uses a very thick, massive Orion-class baseplate disk (the nuclear bomb-type Orion design), but much larger.

I don't see why it should be *that* thick. I bet a ~1mm thick metallic plate will do a lot of damage to any "small" debris (say under 5 cm). A 1mm thick plate is much more feasible.

1mm is just a ballpark figure. Optimal thickness, layering and composition need to be optimized for maximum energy transfer to the impacting debris.

Offline mmeijeri

  • Senior Member
  • *****
  • Posts: 7457
  • Martijn Meijering
  • NL
  • Liked: 76
  • Likes Given: 185
Re: Cleaning up near earth space
« Reply #60 on: 03/04/2009 01:52 PM »
MMOD risk is one subject I don't read about being covered nearly enough from space elevator proponents. An elevator is a sitting duck, unable to avoid anything (a thin sitting duck, but one nonetheless).

See http://www.tethers.com/Hoytether.html. Robert Hoyt is Mr Space Tether.
We will be vic-toooooo-ri-ous!!!

Offline MKremer

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 3911
  • Liked: 13
  • Likes Given: 513
Re: Cleaning up near earth space
« Reply #61 on: 03/04/2009 06:57 PM »

Anyway, my totally pie-in-the-sky idea uses a very thick, massive Orion-class baseplate disk (the nuclear bomb-type Orion design), but much larger.

I don't see why it should be *that* thick. I bet a ~1mm thick metallic plate will do a lot of damage to any "small" debris (say under 5 cm). A 1mm thick plate is much more feasible.

1mm is just a ballpark figure. Optimal thickness, layering and composition need to be optimized for maximum energy transfer to the impacting debris.

It needs to be thick and massive - it's meant to 'sweep up' *all* debris, from micron-sized paint flecks on up to spent rocket stages, dead sats, and other larger remains and various orbital debris.

(which is why I mentioned it would be a risk to *anything* not able to move out of the way by itself)
« Last Edit: 03/04/2009 06:58 PM by MKremer »

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #62 on: 03/05/2009 09:35 PM »
Nope. Because when you incident explode/vaporize/shatter the parts, they emerge at a 180 degree distribution, so in order to gaurantee that  you reduce orbital velocity to all components, you have to hit edge on.

If the vapors emerge with a 180 degree distribution, there will still be an impulse in the direction opposite to the side where the particle was hit. And as long as this impulse is partly in the right direction, you will get deceleration.

If the vapors would emerge with a 360 degree distribution, then you would not get any net impulse. But that is not the case since half the particle is "in the shade".
« Last Edit: 03/07/2009 08:47 AM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #63 on: 03/05/2009 10:36 PM »
It needs to be thick and massive - it's meant to 'sweep up' *all* debris, from micron-sized paint flecks on up to spent rocket stages, dead sats, and other larger remains and various orbital debris.

(which is why I mentioned it would be a risk to *anything* not able to move out of the way by itself)

You want to simplify sweeping up of largest debris items by making "flyswatter" x100 times more massive and expensive? That's extremely inefficient use of $$$. I'd rather make 100 thin flyswatters instead.

Big debris is less numerous, can be easily tracked by radar and thus avoided. A modest upgrade of USAF computers (perhaps only software upgrade will suffice) will get you automatic warning of any collision danger from these.

If you definitely absolutely have to take out some particular dead sat, talk to the Navy. They need to train crews operating AEGIS and Standard. :D

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #64 on: 03/05/2009 11:07 PM »
A modest upgrade of USAF computers (perhaps only software upgrade will suffice) will get you automatic warning of any collision danger from these.


Incorrect.  You have no comprehsion of the issues.  It has nothing to do with software or computing power.  It is tracking assets and and frequency and visibility to those assets

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #65 on: 03/06/2009 04:08 PM »
A modest upgrade of USAF computers (perhaps only software upgrade will suffice) will get you automatic warning of any collision danger from these.

Incorrect.  You have no comprehsion of the issues.  It has nothing to do with software or computing power.  It is tracking assets and and frequency and visibility to those assets

Correct me if I am wrong, but Cosmos/Iridium smashup was predictable based on USAF data, just no one actually checked the data. Neither USAF (because it wasn't their bird) nor Iridium (because then just hoped this won't happen).

A software upgrade at USAF (calculate _all_ possible collisions + send emails to respective sat owners) could have saved Iridium.

If I am wrong and current radar data is not precise enough to predict collisions without too many false positives, upgrading radars is still cheaper than flying the monster plate described. Upgrading radars is also useful for other purposes.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #66 on: 03/06/2009 04:37 PM »
No, because the software already predicts over 400 conjunctions per week for Iridium.   

Doesn't do any good if Iridium ignores them

Again, it isn't the software, it already does it.

The problem is not "upgrading", it is numbers and locations of the radars
« Last Edit: 03/06/2009 04:39 PM by Jim »

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8654
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1124
  • Likes Given: 244
Re: Cleaning up near earth space
« Reply #67 on: 03/06/2009 05:29 PM »
Excellent article on the collision in last weeks theSpaceReview : http://www.thespacereview.com/article/1314/1

Goes into how it is really analyst limited and not as much computer limited.
If you're happy and you know it,
It's your med's!

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #68 on: 03/06/2009 07:07 PM »
The root problem with the current collision is that Iridium isn't / hasn't worked the problem ... and before the bankruptcy they did.

Don't make it bigger than it is - they just are/were gambling. And lost.

The Russians are just being russian. End of story.

You are left with two scenarios currently not dealt with - 1)removing dead sats with long decay orbits before they hit - like the Cosmos, and 2) eliminating collision debris to prevent collateral damage. Fair debate as to cost/benefits for dealing with either.

As to creating an "orbital police", that's silly. Part of the cost of maintaining an orbital asset is a process to cope with the potential for collision. There will always be gamblers (iridium), bad luck/consequential (russians) and willful negligent(russians).
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline khallow

  • Extreme Veteran
  • Full Member
  • ****
  • Posts: 1956
  • Liked: 6
  • Likes Given: 4
Re: Cleaning up near earth space
« Reply #69 on: 03/07/2009 08:18 AM »

Perhaps you might want to do a little work on your own, in particular look at the effectiveness of YAG lasers used in manufacturing, to get some idea of what is required at 10mm distance to vaporize metal, then apply this to meters or kilometers, to get an idea of the issues involved.

Thank you for clarifying that there are "issues" involved. Now what makes it "nonsense"? For example, I can increase the aperture size considerably. For example, the cutting laser example above has an effective aperture of a few millimeters in diameter. What happens if my system has an effective aperture of hundreds of kilometers? And I can increase the power level considerably before issues like atmospheric ionization becomes a problem. And frankly, just hitting the object with intense light pulses every few hours changes its momentum over time.
Karl Hallowell

Offline KelvinZero

  • Senior Member
  • *****
  • Posts: 3868
  • Liked: 626
  • Likes Given: 164
Re: Cleaning up near earth space
« Reply #70 on: 03/07/2009 01:24 PM »
What about putting tons of fine dust or station-keeping propellent into a reversed orbit?

If space junk sits up there for a long time, then wouldnt these do the same? Because they are very fine they would only be a minor nuisance to large objects, however they would apply a significant drag to small objects, especially paint flecks etc.

We wouldnt even need to send up mass specifically for this purpose. We have to expend propellent to keep things in orbit anyway. If this propellent was ejected at about 16km/s we could encourage it to build up in an orbit roughly opposite the satellites orbit.

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #71 on: 03/07/2009 05:54 PM »
I do not think adding debris is the way to go. Unless an object is under our direct control that we can change direction and orbit manually our selves then we would in effect only be adding to the problem we are trying to eliminate. Much is being said of lasers, however at the speeds we are talking of many of these object would only be exposed to the laser for short periods, the sun itself has the debris under its exposure for a lot longer and has not made much difference in its orbital characteristics.


Is there any study being done to find some way to attract the debris to a certain point or orbit?

Apart from altering its speed and orbit, what else could be used to bring the debris under our control?

A lot of debris is being monitored, what is the estimate on debris not being monitored?

Is there any small area or areas that can be said "x amount of debris will pass this area in x amount of time" ?

What other questions need to be addressed to start someone thinking of a solution?


Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #72 on: 03/07/2009 06:21 PM »

1.  Is there any study being done to find some way to attract the debris to a certain point or orbit?

2.  Apart from altering its speed and orbit, what else could be used to bring the debris under our control?

3.  Is there any small area or areas that can be said "x amount of debris will pass this area in x amount of time" ?

4.  What other questions need to be addressed to start someone thinking of a solution?


1.  No

2.  capture

3.  no

4.  None, because the solution for now is not to generate debris and if it is followed then nothing else is needed

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #73 on: 03/07/2009 06:43 PM »
What happens if my system has an effective aperture of hundreds of kilometers?

An aperture of hundreds of kilometers might be a little technically challenging... I think the biggest aperture you can realistically build is about 10m, like the biggest optical telescopes existing today.

But anyway, the boeing YAL-1 (if it works) is an existence proof that it is possible to focus laser light over several 100km even if the sender is in the atmosphere.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline dunderwood

  • Full Member
  • *
  • Posts: 158
  • Liked: 6
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #74 on: 03/07/2009 08:15 PM »

An aperture of hundreds of kilometers might be a little technically challenging... I think the biggest aperture you can realistically build is about 10m, like the biggest optical telescopes existing today.


You could build a sparse aperture array, and get an effective aperture much larger than what you can actually build using a monolithic lens.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8654
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1124
  • Likes Given: 244
Re: Cleaning up near earth space
« Reply #75 on: 03/08/2009 08:02 PM »

But anyway, the boeing YAL-1 (if it works) is an existence proof that it is possible to focus laser light over several 100km even if the sender is in the atmosphere.

It is also a chemical laser that only has enough chemicals to fire twenty times before it has to land and be loaded up again.


« Last Edit: 03/08/2009 08:02 PM by kevin-rf »
If you're happy and you know it,
It's your med's!

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #76 on: 03/08/2009 11:14 PM »
There is no reasonable cost way of sweeping space clean  :)

Best answer is don't dirty it.

If you must play with ray guns, an on orbit particle beam weapon might get you enough vapor pressure to matter, the troubles are: beam coherence (e.g. distance), beam current (accelerator weight/power), wiggler/buncher - to avoid charge dissipation/impedance issues(size).

Also superpowers would blame it every time their satellite would die - witness Russians blaming Orbital Express (obviously it sabotaged things ...).
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline KelvinZero

  • Senior Member
  • *****
  • Posts: 3868
  • Liked: 626
  • Likes Given: 164
Re: Cleaning up near earth space
« Reply #77 on: 03/09/2009 07:54 AM »
I do not think adding debris is the way to go. Unless an object is under our direct control that we can change direction and orbit manually our selves then we would in effect only be adding to the problem we are trying to eliminate.

Not really. You are adding a material that is at worst a nuisance to remove objects that could be catastrophic. You could say it is under our direct control because its effects and decay are predictable and it is targeted very accurately to only significantly affect very small manmade objects (those orbiting in the direction of the earths rotation with a very high surface area to mass ratio).

The way I see it, barring natural removal, every ton of this safe material you put up would neutralise itself against a ton of dangerous space junk, even and especially if that junk is distributed in millons of fragments.

Also perhaps it is possible to design a material that removes itself, eg eventually ionises and interacts with the magnetic field or solar wind.

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #78 on: 03/09/2009 09:48 AM »
There is no reasonable cost way of sweeping space clean  :)

Depends on what you define as reasonable.

A single large earth observation satellite like MetOp-A costs close to a billion euros. If you add the value of all satellites that are using high LEO (polar and sun-synchronous earth observation satellites and communications constellations), you get significantly more than ten billion USD. So the high LEO environment is worth a lot. It would make sense to invest 10% of that value so that the high LEO environment remains usable.

Quote
Best answer is don't dirty it.

Of course that would have been best. But it is a bit too late for that.

Quote
If you must play with ray guns, an on orbit particle beam weapon might get you enough vapor pressure to matter, the troubles are: beam coherence (e.g. distance), beam current (accelerator weight/power), wiggler/buncher - to avoid charge dissipation/impedance issues(size).

Also superpowers would blame it every time their satellite would die - witness Russians blaming Orbital Express (obviously it sabotaged things ...).

Why particle beams? Lasers have made tremendous improvements in the last 20 years. There are infrared semiconductor lasers with 50% efficiency. And if you use those to pump a Nd:YAG pulsed laser, you get an overall system efficiency of >20%. That is extremely impressive.

If your laser is in orbit, you have no problems whatsoever with atmospheric turbulence. You are only limited by diffraction. So you don't need adaptive optics for your targeting system. The only tiny problem is where you get the 100kW(e) to power such a laser. On earth that is a trivial amount of power, in space not so much.

By the way: The russians will blame you whenever you do anything in space. And if you don't do something for that.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #79 on: 03/09/2009 09:52 AM »

But anyway, the boeing YAL-1 (if it works) is an existence proof that it is possible to focus laser light over several 100km even if the sender is in the atmosphere.

It is also a chemical laser that only has enough chemicals to fire twenty times before it has to land and be loaded up again.

You would have to replace the laser (probably by a diode-pumped Nd:YAG laser) since for space debris removal you want a relatively small pulsed laser instead of an extremely powerful continuous laser. But the targeting system could be reused.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8534
  • South coast of England
  • Liked: 360
  • Likes Given: 157
Re: Cleaning up near earth space
« Reply #80 on: 03/09/2009 10:32 AM »
{snip}

If your laser is in orbit, you have no problems whatsoever with atmospheric turbulence. You are only limited by diffraction. So you don't need adaptive optics for your targeting system. The only tiny problem is where you get the 100kW(e) to power such a laser. On earth that is a trivial amount of power, in space not so much.

The solar panels on the ISS generate 131 kW of power so 100kW(e) is possible.  At that sort of power the satellite could be equipped with Hall Effect or VASIMR thrusters, allowing the laser satellite to change its orbit.

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #81 on: 03/09/2009 10:47 AM »
{snip}

If your laser is in orbit, you have no problems whatsoever with atmospheric turbulence. You are only limited by diffraction. So you don't need adaptive optics for your targeting system. The only tiny problem is where you get the 100kW(e) to power such a laser. On earth that is a trivial amount of power, in space not so much.

The solar panels on the ISS generate 131 kW of power so 100kW(e) is possible.  At that sort of power the satellite could be equipped with Hall Effect or VASIMR thrusters, allowing the laser satellite to change its orbit.

Possible, yes. But not cheap. Nowadays you could do much better than the ISS solar arrays mass wise, but it would still be a huge satellite. You would need a heavy EELV to launch that beast.

Of course you could power an electric propulsion system with that kind of power. But I think you would not have to change orbit to get close to most space debris. Just launch into a 28 degree inclination, 500km altitude circular orbit from the cape. That would put you right in the middle of the high LEO space debris cloud, and every piece of debris will come sufficiently close (~400km) to you in time.
« Last Edit: 03/09/2009 01:00 PM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #82 on: 03/09/2009 06:11 PM »
There is no reasonable cost way of sweeping space clean  :)

Depends on what you define as reasonable.

A single large earth observation satellite like MetOp-A costs close to a billion euros. If you add the value of all satellites that are using high LEO (polar and sun-synchronous earth observation satellites and communications constellations), you get significantly more than ten billion USD. So the high LEO environment is worth a lot. It would make sense to invest 10% of that value so that the high LEO environment remains usable.

You are correct, but try to think like a businessman (which is how we get into this problem - no self respecting engineer would abandon a conflict monitoring process). If they get the idea that its just odds, a form of gambling that replaces a budget item with $0 and they can not book the contingency liability because they can just lie, they'll do it in a heartbeat. The only way you can fight this is put a gun to their head and cock the trigger.

They don't see it as an active cost to the business - so they don't believe it exists for them. Until they do, you can't get traction.

Quote
Quote
Best answer is don't dirty it.

Of course that would have been best. But it is a bit too late for that.

Not really - people talk themselves into working around the problem by avoiding the trash zones. Then they think they'll just not have another  accident. That's exactly what will happen here.
Quote
Quote
If you must play with ray guns, an on orbit particle beam weapon might get you enough vapor pressure to matter, the troubles are: beam coherence (e.g. distance), beam current (accelerator weight/power), wiggler/buncher - to avoid charge dissipation/impedance issues(size).

Also superpowers would blame it every time their satellite would die - witness Russians blaming Orbital Express (obviously it sabotaged things ...).

Why particle beams? Lasers have made tremendous improvements in the last 20 years. There are infrared semiconductor lasers with 50% efficiency. And if you use those to pump a Nd:YAG pulsed laser, you get an overall system efficiency of >20%. That is extremely impressive.

Lasers are very efficient at converting energy, not efficient at converting energy to metal vapor/explosions - look at the end to end process here. Particle beams heat metal/glass/electronics/composites much more efficiently.
Quote

If your laser is in orbit, you have no problems whatsoever with atmospheric turbulence. You are only limited by diffraction. So you don't need adaptive optics for your targeting system. The only tiny problem is where you get the 100kW(e) to power such a laser. On earth that is a trivial amount of power, in space not so much.

Correct. Even better, you can create the lasing cavity in interesting ways that can take advantage of the hard vacuum of space to get greater efficiencies than on earth.

It's harder for particle beams, and they are heavier as well. But you get more effect of what you want per watt.
Quote

By the way: The russians will blame you whenever you do anything in space. And if you don't do something for that.
I know - that's how they make life more interesting. But I guarantee that a particle beam weapon in orbit will get their attention.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #83 on: 03/09/2009 06:17 PM »

But anyway, the boeing YAL-1 (if it works) is an existence proof that it is possible to focus laser light over several 100km even if the sender is in the atmosphere.

It is also a chemical laser that only has enough chemicals to fire twenty times before it has to land and be loaded up again.

You would have to replace the laser (probably by a diode-pumped Nd:YAG laser) since for space debris removal you want a relatively small pulsed laser instead of an extremely powerful continuous laser. But the targeting system could be reused.
You need a bulk switched semiconductor laser with high duty cycle feeding an optically coupled array of YAG crystals with a very large radiator to cold soak the bulk switching and crystals. Very severe thermal issues here.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #84 on: 03/09/2009 06:24 PM »
{snip}

If your laser is in orbit, you have no problems whatsoever with atmospheric turbulence. You are only limited by diffraction. So you don't need adaptive optics for your targeting system. The only tiny problem is where you get the 100kW(e) to power such a laser. On earth that is a trivial amount of power, in space not so much.

The solar panels on the ISS generate 131 kW of power so 100kW(e) is possible.  At that sort of power the satellite could be equipped with Hall Effect or VASIMR thrusters, allowing the laser satellite to change its orbit.

Possible, yes. But not cheap. Nowadays you could do much better than the ISS solar arrays mass wise, but it would still be a huge satellite. You would need a heavy EELV to launch that beast.

Of course you could power an electric propulsion system with that kind of power. But I think you would not have to change orbit to get close to most space debris. Just launch into a 28 degree inclination, 500km altitude circular orbit from the cape. That would put you right in the middle of the high LEO space debris cloud, and every piece of debris will come sufficiently close (~400km) to you in time.
You charge a bank of capacitors, so the size of the array is set more by the firing rate / discharge. You don't use continuous current.

As an aside, VASIMIR and/or other plasma engines are basically unfocused particle beams - you could use the same equipment to change orbit that you use to generate a particle beam weapon. Also, considering the MHD properties, you can generate plasmas from nuclear sources as well very "weight/size" efficiently, so current limits don't necessarily require 4 Shuttle equivalent launches of PV arrays.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8534
  • South coast of England
  • Liked: 360
  • Likes Given: 157
Re: Cleaning up near earth space
« Reply #85 on: 03/09/2009 07:52 PM »
Solar panel technology has moved on since the ISS was designed so only a single pair of panels may be needed.

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #86 on: 03/09/2009 08:55 PM »
There is no reasonable cost way of sweeping space clean  :)

Depends on what you define as reasonable.

A single large earth observation satellite like MetOp-A costs close to a billion euros. If you add the value of all satellites that are using high LEO (polar and sun-synchronous earth observation satellites and communications constellations), you get significantly more than ten billion USD. So the high LEO environment is worth a lot. It would make sense to invest 10% of that value so that the high LEO environment remains usable.

You are correct, but try to think like a businessman (which is how we get into this problem - no self respecting engineer would abandon a conflict monitoring process). If they get the idea that its just odds, a form of gambling that replaces a budget item with $0 and they can not book the contingency liability because they can just lie, they'll do it in a heartbeat. The only way you can fight this is put a gun to their head and cock the trigger.

They don't see it as an active cost to the business - so they don't believe it exists for them. Until they do, you can't get traction.

The problem is that everybody has gotten used to treating LEO as an infinite resource. And it turns out that it is finite.

This is an old economic problem: the global utility function would be optimized by action A, but the individual utility function is optimized by action B. Guess what people will do...

Statists would call this a market failure. Libertarians would say that the problem is that a resource that has no owner will be used as if it was free. In any case, it is difficult to get the actors to choose action A if action B is more profitable for them in the short term.

In the long term, the major space faring nations will have to define some code of conduct for using LEO, and enforce it by sanctioning everybody that violates that code of conduct. There are beginnings of such a code of conduct: for example you are supposed to at least vent your upper stage to prevent upper stage explosions. You are supposed to deorbit your satellite at the end of its life if possible. And if it is a GEO bird you are supposed to use the last drops of propellant to send it to a graveyard orbit. But as far as I know there are no real sanctions if you fail to do any of this. Kind of like the united nations  ;)

I know that at least the europeans take this code of conduct very seriously. For example they usually won't allow small sats without propulsion system as secondary payloads for high LEO missions. The russians and the chinese probably just don't care.

It would still be very reassuring to have the capability to do something about the problem if something goes wrong. On the oceans you have the law of the sea, but to give people an incentive to actually obey this law you also have the US navy...

Quote
Not really - people talk themselves into working around the problem by avoiding the trash zones. Then they think they'll just not have another  accident. That's exactly what will happen here.

Avoiding the trash zones is not always possible. For example a project I am involved with requires a sun-synchronous orbit with the exact same parameters as an existing satellite. It is absolutely impossible to change the orbital parameters even a bit to avoid debris. And flying a collision avoidance maneuver is a major PITA if you are flying two satellites in close formation.

Especially the people doing earth observations are very worried about the situation. Most of them use relatively high altitude, high inclination orbits that are right in the middle of the zone polluted by that stupid chinese ASAT demo and the recent collision.

Quote
Lasers are very efficient at converting energy, not efficient at converting energy to metal vapor/explosions - look at the end to end process here. Particle beams heat metal/glass/electronics/composites much more efficiently.

One nice thing about particle beams is that most materials are affected by them in almost the same way, whereas with a laser you have large variation between e.g. a piece of mirror and a piece of black plastic. But a laser is much easier to focus over large distances, so I think it will still be the better choice.

The total amount of energy you need to deorbit all small space debris is not that high, so you can probably live with inefficient coupling.

Quote
Correct. Even better, you can create the lasing cavity in interesting ways that can take advantage of the hard vacuum of space to get greater efficiencies than on earth.

It's harder for particle beams, and they are heavier as well. But you get more effect of what you want per watt.

Wouldn't a particle beam also have problems because of the earth magnetic field? Or are you talking about a neutral beam? In any case, my gut feeling is that the laser still wins.

Quote
I know - that's how they make life more interesting. But I guarantee that a particle beam weapon in orbit will get their attention.

If the russians had a) the money and b) the need to put such a thing in orbit, they would not hesitate for a second just because the USA might be irritated. Russians being irritated is just something you will have to live with if you do anything significant in space...

Quote
You need a bulk switched semiconductor laser with high duty cycle feeding an optically coupled array of YAG crystals with a very large radiator to cold soak the bulk switching and crystals. Very severe thermal issues here.

I completely forgot about that. Getting rid of heat in space is almost as difficult as collecting energy. So in addition to the huge solar array, this orbital brush (laser battle station sounds so militaristic) will have some huge radiators.

Quote
As an aside, VASIMIR and/or other plasma engines are basically unfocused particle beams - you could use the same equipment to change orbit that you use to generate a particle beam weapon.

Now that's an interesting concept: an electric engine that also doubles as a particle beam emitter. Which of the existing electric propulsion systems would have the most coherent beam? Hall effect, VASIMIR or ion engines? I still think it would be difficult to get a significant effect on a target a useful distance (>100km) away.

Quote
Also, considering the MHD properties, you can generate plasmas from nuclear sources as well very "weight/size" efficiently, so current limits don't necessarily require 4 Shuttle equivalent launches of PV arrays.

I think nuclear power is unrealistic. But solar power is not as bad as the ISS suggests. The dawn spacecraft has a weight of 1250kg and a solar array producing 10kW at 1AU. And that is a complete spacecraft.

So a 100kW solar array should be possible for significantly less than 10 tons.
« Last Edit: 03/09/2009 09:04 PM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #87 on: 03/09/2009 10:16 PM »

The problem is that everybody has gotten used to treating LEO as an infinite resource. And it turns out that it is finite.

It's called "the rape of the commons". Quite a bit of experience with it.

Quote
This is an old economic problem: the global utility function would be optimized by action A, but the individual utility function is optimized by action B. Guess what people will do...

Statists would call this a market failure. Libertarians would say that the problem is that a resource that has no owner will be used as if it was free. In any case, it is difficult to get the actors to choose action A if action B is more profitable for them in the short term.

In the long term, the major space faring nations will have to define some code of conduct for using LEO, and enforce it by sanctioning everybody that violates that code of conduct. There are beginnings of such a code of conduct: for example you are supposed to at least vent your upper stage to prevent upper stage explosions. You are supposed to deorbit your satellite at the end of its life if possible. And if it is a GEO bird you are supposed to use the last drops of propellant to send it to a graveyard orbit. But as far as I know there are no real sanctions if you fail to do any of this. Kind of like the united nations  ;)

Note the current fun and games with Chinese ships happening right now. Violates international law. Only matters when they wish to. Sanctions are a joke.

Quote
I know that at least the europeans take this code of conduct very seriously. For example they usually won't allow small sats without propulsion system as secondary payloads for high LEO missions. The russians and the chinese probably just don't care.

It would still be very reassuring to have the capability to do something about the problem if something goes wrong. On the oceans you have the law of the sea, but to give people an incentive to actually obey this law you also have the US navy...

Note the Chinese are playing hardball with the US Navy.
Quote

Quote
Not really - people talk themselves into working around the problem by avoiding the trash zones. Then they think they'll just not have another  accident. That's exactly what will happen here.

Avoiding the trash zones is not always possible. For example a project I am involved with requires a sun-synchronous orbit with the exact same parameters as an existing satellite. It is absolutely impossible to change the orbital parameters even a bit to avoid debris. And flying a collision avoidance maneuver is a major PITA if you are flying two satellites in close formation.

Same issue with halo orbits. But at least you don't have high differential speed in these cases, so even if they "bump", the debris isn't like bullets.

Speaking of which, it would be a royal PITA to clean up L1/L2 points.
Quote

Especially the people doing earth observations are very worried about the situation. Most of them use relatively high altitude, high inclination orbits that are right in the middle of the zone polluted by that stupid chinese ASAT demo and the recent collision.

Quote
Lasers are very efficient at converting energy, not efficient at converting energy to metal vapor/explosions - look at the end to end process here. Particle beams heat metal/glass/electronics/composites much more efficiently.

One nice thing about particle beams is that most materials are affected by them in almost the same way, whereas with a laser you have large variation between e.g. a piece of mirror and a piece of black plastic. But a laser is much easier to focus over large distances, so I think it will still be the better choice.

Actually you can get beam coherence of particles just like photons - the technique is used in accelerators/particle storage rings. While you can't use a cavity (the particles stick/erode mirrors) like a laser, you use microwaves to cascade/phase particle groups.

You can focus lasers in the "near field" (where the geometry of the "lens" is significant in size to the source/sink foci) , in the "far field" case you are left with the size of the beam determined by the diameter needed to keep from being diffracted (e.g. parallel and not pinhole). That vacuum isotropy allows you to reach diffraction limits (actually slightly better for a weird effect with certain optical cavities - takes some quantum mechanics to describe) means you can just barely do this.
Quote

The total amount of energy you need to deorbit all small space debris is not that high, so you can probably live with inefficient coupling.

Not so sure of this given coupling effects we previously described. But I guarantee with a particle beam you can vaporize/explode at tens of miles with current(hah!) techniques - you will have sufficient, measurable dV.
Quote

Quote
Correct. Even better, you can create the lasing cavity in interesting ways that can take advantage of the hard vacuum of space to get greater efficiencies than on earth.

It's harder for particle beams, and they are heavier as well. But you get more effect of what you want per watt.

Wouldn't a particle beam also have problems because of the earth magnetic field? Or are you talking about a neutral beam? In any case, my gut feeling is that the laser still wins.

It has to be compensated for given tracking (right hand rule), and shooting down polar orbit debris would have interesting issues. You don't want a neutral beam because a) they don't couple to metals/glasses as well and b) they are more inefficient to generate (unless you want to play with nuclear items).
Quote

Quote
I know - that's how they make life more interesting. But I guarantee that a particle beam weapon in orbit will get their attention.

If the russians had a) the money and b) the need to put such a thing in orbit, they would not hesitate for a second just because the USA might be irritated. Russians being irritated is just something you will have to live with if you do anything significant in space...

The main reason they'd complain is because of the budget/work/time they'd need to duplicate/better such work - throws them off plan.  :)
Quote


Quote
You need a bulk switched semiconductor laser with high duty cycle feeding an optically coupled array of YAG crystals with a very large radiator to cold soak the bulk switching and crystals. Very severe thermal issues here.

I completely forgot about that. Getting rid of heat in space is almost as difficult as collecting energy. So in addition to the huge solar array, this orbital brush (laser battle station sounds so militaristic) will have some huge radiators.

Yes - and even worse is the thermal runaway - you need more than just a large passive radiator.
Quote

Quote
As an aside, VASIMIR and/or other plasma engines are basically unfocused particle beams - you could use the same equipment to change orbit that you use to generate a particle beam weapon.

Now that's an interesting concept: an electric engine that also doubles as a particle beam emitter. Which of the existing electric propulsion systems would have the most coherent beam? Hall effect, VASIMIR or ion engines? I still think it would be difficult to get a significant effect on a target a useful distance (>100km) away.

Anything that generates plasmas - the same technique you use for propulsion is to increase current flow. The main difference is in what is referred to as "beam control". Electron accelerators, like the famous SLAC LINAC have refined beam control to a fine art.

Do some research on the topic - you're just not familiar with it. Just as you might also be presuming that high energy laser vaporization is easy - its not as easy as it seems. Details, details...
Quote

Quote
Also, considering the MHD properties, you can generate plasmas from nuclear sources as well very "weight/size" efficiently, so current limits don't necessarily require 4 Shuttle equivalent launches of PV arrays.

I think nuclear power is unrealistic. But solar power is not as bad as the ISS suggests. The dawn spacecraft has a weight of 1250kg and a solar array producing 10kW at 1AU. And that is a complete spacecraft.

So a 100kW solar array should be possible for significantly less than 10 tons.

Dunno. Not my department. Just notice that for the ISS, those array's push Shuttle limits - probably for good reason.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #88 on: 03/09/2009 10:59 PM »
It would still be very reassuring to have the capability to do something about the problem if something goes wrong. On the oceans you have the law of the sea, but to give people an incentive to actually obey this law you also have the US navy...
Note the Chinese are playing hardball with the US Navy.

Makes sense. Whenever there is a new president, somebody tests his resolve. Maybe they get lucky and obama will stop surveillance of the south china sea to avoid "provoking" the chinese.

Quote
Same issue with halo orbits. But at least you don't have high differential speed in these cases, so even if they "bump", the debris isn't like bullets.

Speaking of which, it would be a royal PITA to clean up L1/L2 points.

At least the relative velocities are small, so you could collect all the big bits with a space tug.

Quote
Actually you can get beam coherence of particles just like photons - the technique is used in accelerators/particle storage rings. While you can't use a cavity (the particles stick/erode mirrors) like a laser, you use microwaves to cascade/phase particle groups.

You can focus lasers in the "near field" (where the geometry of the "lens" is significant in size to the source/sink foci) , in the "far field" case you are left with the size of the beam determined by the diameter needed to keep from being diffracted (e.g. parallel and not pinhole). That vacuum isotropy allows you to reach diffraction limits (actually slightly better for a weird effect with certain optical cavities - takes some quantum mechanics to describe) means you can just barely do this.

There is no strict boundary between near field and far field. At least theoretically you can focus on arbitrary large distances. Of course the light in the focus will not be a point, but a disk with a diameter determined by the diffraction limit.

I guess you could say that the far field begins when the disk created by the diffraction limit when focusing on a point is as large as the aperture. But for a large (>1m) aperture, that distance is >200km away.

Quote
Not so sure of this given coupling effects we previously described. But I guarantee with a particle beam you can vaporize/explode at tens of miles with current(hah!) techniques - you will have sufficient, measurable dV.

If you can really get sufficient energy on target over large distances then a particle beam might indeed be the better choice. But the laser will also work. Even a "worst case" object such as a piece of a broken mirrors will have some spots where it is not completely reflective (the back side and/or the edges).

Quote
Quote
Wouldn't a particle beam also have problems because of the earth magnetic field? Or are you talking about a neutral beam? In any case, my gut feeling is that the laser still wins.

It has to be compensated for given tracking (right hand rule), and shooting down polar orbit debris would have interesting issues. You don't want a neutral beam because a) they don't couple to metals/glasses as well and b) they are more inefficient to generate (unless you want to play with nuclear items).

Then you need an accurate model of the earth magnetic field and/or a way to observe the beam and walk it into the target.

Quote
Quote
Quote
You need a bulk switched semiconductor laser with high duty cycle feeding an optically coupled array of YAG crystals with a very large radiator to cold soak the bulk switching and crystals. Very severe thermal issues here.

I completely forgot about that. Getting rid of heat in space is almost as difficult as collecting energy. So in addition to the huge solar array, this orbital brush (laser battle station sounds so militaristic) will have some huge radiators.

Yes - and even worse is the thermal runaway - you need more than just a large passive radiator.

But the radiator to get rid of the low temperature waste heat is probably the biggest mass item. The cooling system (pumped liquid) can be designed similar to what you do on earth.

Quote
Quote
Quote
As an aside, VASIMIR and/or other plasma engines are basically unfocused particle beams - you could use the same equipment to change orbit that you use to generate a particle beam weapon.

Now that's an interesting concept: an electric engine that also doubles as a particle beam emitter. Which of the existing electric propulsion systems would have the most coherent beam? Hall effect, VASIMIR or ion engines? I still think it would be difficult to get a significant effect on a target a useful distance (>100km) away.

Anything that generates plasmas - the same technique you use for propulsion is to increase current flow. The main difference is in what is referred to as "beam control". Electron accelerators, like the famous SLAC LINAC have refined beam control to a fine art.

But a particle accelerator that creates coherent particle bunches would look completely different than an ion engine where you mainly care about high currents and don't really care about coherence as long as the ions are going roughly in the right direction.

Quote
Do some research on the topic - you're just not familiar with it. Just as you might also be presuming that high energy laser vaporization is easy - its not as easy as it seems. Details, details...

I don't claim to be an expert in this field. I have some physics knowledge, but nowadays I work as a software engineer in space operations. And I am not saying that it is easy, just that it is possible.

Quote
Quote
I think nuclear power is unrealistic. But solar power is not as bad as the ISS suggests. The dawn spacecraft has a weight of 1250kg and a solar array producing 10kW at 1AU. And that is a complete spacecraft.

So a 100kW solar array should be possible for significantly less than 10 tons.

Dunno. Not my department. Just notice that for the ISS, those array's push Shuttle limits - probably for good reason.

First of all, the shuttle has surprisingly little payload to that stupid orbit the ISS is in because of the russians. And second, the ISS solar arrays are a 20 year old design, and 20 years are a long time when it comes to semiconductors.

The dawn solar array is an example of a state of the art solar array. Obviously it has a specific power of significantly more than 10kW/t or 10W/kg. So it follows that you can get 100kW in 10 tons if you are willing to pay for the ridiculously expensive triple junction cells.
« Last Edit: 03/09/2009 11:06 PM by rklaehn »
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #89 on: 03/15/2009 09:30 AM »
It seems most ideas tend to favour some laser or particle beam.
My fear of this is what happens to the part of the beam that does not connect the target but continues to whatever is in its path. If pointed to earth it will connect earth’s atmosphere. If it continues through space,  mmm....  would that not cause some unknown signal to be sent out or damage some asteroid or comet that could wander into its path?

Oh, well, maybe it also means nothing.

Offline rklaehn

  • telemetry plumber
  • Full Member
  • ****
  • Posts: 1226
  • germany
    • www.heavens-above.com
  • Liked: 126
  • Likes Given: 193
Re: Cleaning up near earth space
« Reply #90 on: 03/15/2009 09:55 AM »
It seems most ideas tend to favour some laser or particle beam.
My fear of this is what happens to the part of the beam that does not connect the target but continues to whatever is in its path. If pointed to earth it will connect earth’s atmosphere. If it continues through space,  mmm....  would that not cause some unknown signal to be sent out or damage some asteroid or comet that could wander into its path?

Oh, well, maybe it also means nothing.

The problem with both laser beams and particle beams is to keep the beam diameter small enough so that sufficient energy arrives at the target. Over larger distances, the divergence of the beam will make it completely harmless.

A ground-based installation would obviously never fire towards earth. And a space-based weapon would fire almost horizontally for maximum effect, so it would not fire towards earth either.

You should probably avoid firing the beam if there is an active satellite in view though.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline DrCoffee

  • Member
  • Posts: 10
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #91 on: 03/15/2009 10:15 AM »
Right in the beginning Blackstar said “The only realistic policy is to try and reduce the amount of junk that is produced from each launch.”

I know this is a major change in direction within this thread, it might even warrant opening a new thread.

If a totally clean launch were possible, the growth in space debris would be limited to a large extent.

Some time back I saw some investigation in using electromagnets to launch object…. I did not see or notice if they had actually been able to place an object into orbit and was wondering if anyone knows of these experiments and what has come of them..

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #92 on: 03/15/2009 11:18 AM »
It is not just launch that causes the debris, spacecraft are part of the problem.

As for electromagnets, not really viable for spacecraft, only bulk material.  Nothing has yet to be orbited. Also it doesn't solve the debris problem

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8654
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1124
  • Likes Given: 244
Re: Cleaning up near earth space
« Reply #93 on: 04/02/2009 06:50 PM »


Interesting article on the wires, calling for active removal...

http://news.yahoo.com/s/ap/20090402/ap_on_re_eu/eu_sci_europe_space_junk
If you're happy and you know it,
It's your med's!

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: Cleaning up near earth space
« Reply #94 on: 04/02/2009 08:21 PM »
If it [laser] continues through space,  mmm....  would that not cause some unknown signal to be sent out or damage some asteroid or comet that could wander into its path?

Yeah right, poor two-mile wide asteroid can be badly hurt. Gotta be careful...

Offline khallow

  • Extreme Veteran
  • Full Member
  • ****
  • Posts: 1956
  • Liked: 6
  • Likes Given: 4
Re: Cleaning up near earth space
« Reply #95 on: 04/02/2009 09:34 PM »
Right in the beginning Blackstar said “The only realistic policy is to try and reduce the amount of junk that is produced from each launch.”

I know this is a major change in direction within this thread, it might even warrant opening a new thread.

If a totally clean launch were possible, the growth in space debris would be limited to a large extent.

This would just delay the need for orbital cleanup. Bottom line is human activity in orbit creates debris. We can reduce the rate at that debris is created, and for low orbits where air resistance deorbits debris on the order of decades or shorter, that may be enough to keep those regions viable. But for orbits where debris can loiter for centuries or longer, that isn't good enough.
Karl Hallowell

Offline nooneofconsequence

  • Full Member
  • ****
  • Posts: 1391
  • no one is playing fair ...
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #96 on: 04/08/2009 06:26 PM »
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4417
  • Liked: 189
  • Likes Given: 382
Re: Cleaning up near earth space
« Reply #97 on: 04/08/2009 07:11 PM »
I completely forgot about that. Getting rid of heat in space is almost as difficult as collecting energy. So in addition to the huge solar array, this orbital brush (laser battle station sounds so militaristic) will have some huge radiators.
Depends if you need to deal with high thermo loads continuously or for just a short peak period.
If it's just for a short duty cycle vs continuously then dealing with the heat is no longer as big an issue.
Many high power laser can't fire continuously anyway they'll melt down or they are pulsed lasers anyway.

If you only need to deal with a 100KW or more thermo load for only a few minutes at a time which is all you'll have with any given piece of space debris then you can make use of a flash evaporator or even thermo mass to deal with the peak thermo load.

A few tons of water and a modest radiator no larger then those on ISS or even the shuttle might be all you'll need cooling wise.
« Last Edit: 04/08/2009 07:12 PM by Patchouli »

Offline Cbased

  • Full Member
  • **
  • Posts: 278
  • Melbourne, Australia
  • Liked: 1
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #98 on: 04/10/2009 07:53 AM »
I have to say I don't like the idea of having lasers and/or particle guns/cannons in space even for a good cause - still looks too similar to weapons to me.

I agree with the "no new debris" agenda - it is the best we can do at t he moment.

And I've got 2 questions:
1. Low altitude debris pieces deorbit in a matter of days. Higher altitude - months/year and so on. Is there a table that will demonstrate the approximate time it takes debris to reenter as a function of an altitude?

2. The new planned Russian spacecraft in the list of requirements has got a task of capturing and deorbiting objects in space/debris. Does anyone know more about it? Are they planning to remove non-funtional satellites or real debris pieces???


Offline Vacuum.Head

  • Full Member
  • *
  • Posts: 154
  • Still in the Cradle
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #99 on: 04/10/2009 09:05 AM »
http://news.bbc.co.uk/1/hi/sci/tech/7916582.stm
Comprehensive report by the BEEB including ESA's proposed Space Situational Awareness capability.
----------------------------------------
"...all the Universe or nothing." Oswald Cabal
["Shape of Things to Come" U.K. 1936  (Dir. William Cameron Menzies)]

Offline Spacenick

  • Full Member
  • ***
  • Posts: 303
  • Liked: 0
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #100 on: 04/10/2009 10:37 AM »
If lasers than I think they should be based on earth, that eliminates the cooling and power problems and makes them much cheaper they might even be converted from existing reasearch facilities.
Have you seen the huge block used to stop the beam of the LHC?
If we could send an LHC Proton beam into space with a very high precision I'm pretty sure it could deorbit debris as is.
The beam dump of the LHC  (http://en.wikipedia.org/wiki/Beam_dump)
has to dissipate 362 MJ in 92 microseconds. If that wouldn't blow a satellite into vapor I don't know what will. So all we have to do is replace the LHC beam dump with a way of shooting the beam into space.
Make the elevation fixed but the azimuth changeable and there you have you super massive energy gun.

And the best thing is it wouldn't even be so expensive as it wouldn't stop the LHC from doing it's normal science program, though it would influence the timing a little bit.
« Last Edit: 04/10/2009 10:49 AM by Spacenick »

Offline Vacuum.Head

  • Full Member
  • *
  • Posts: 154
  • Still in the Cradle
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #101 on: 04/10/2009 12:29 PM »
Would it punch through the atmosphere? Perhaps it's time to build the AELHC (An Even Larger Hadron Collider) on the Moon! :D
Mind you thinking seriously about it: Cheap vacuum; cheap power; cheap low temperatures...
----------------------------------------
"...all the Universe or nothing." Oswald Cabal
["Shape of Things to Come" U.K. 1936  (Dir. William Cameron Menzies)]

Offline Spacenick

  • Full Member
  • ***
  • Posts: 303
  • Liked: 0
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #102 on: 04/10/2009 02:12 PM »
In my absolutely uneducated opinion I'd guess that it has more than enough energy to punch through the atmosphere, due to the power it might make the air expand fast enough to create a sonic boom and maybe a plasma.

Offline Vacuum.Head

  • Full Member
  • *
  • Posts: 154
  • Still in the Cradle
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #103 on: 04/10/2009 11:52 PM »
Thank you for a very informative post!
----------------------------------------
"...all the Universe or nothing." Oswald Cabal
["Shape of Things to Come" U.K. 1936  (Dir. William Cameron Menzies)]

Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17812
  • Westphal, Nova Scotia
  • Liked: 464
  • Likes Given: 4605
Re: Cleaning up near earth space
« Reply #104 on: 05/13/2009 02:04 AM »
I figured this deserved a bump based on the findings from a recent conference in Montreal, Canada at McGill University. Looks like removing debris is on the table!

http://www.spaceref.com/news/viewpr.html?pid=28192

From the report by Spaceref.com:
"Additionally, researchers are moving towards the next phase of scientific study. “There is an emerging consensus among the technical community that simply preventing creation of new debris is not going to be enough,” Weeden emphasized.

“At some point we will need to actively remove debris from orbit. Fortunately, new studies are showing that removing as few as five or six objects per year could stabilize the debris population over the long term. The big question right now is which objects to remove first and what is the best method to do so.”

Here is a link to the organization behind all this and the specific site:
http://www.secureworldfoundation.org/index.php?id=14&page=Mitigation_of_Orbital_Debris
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9910
  • Lansing MI
  • Liked: 252
  • Likes Given: 31
Re: Cleaning up near earth space
« Reply #105 on: 05/13/2009 02:15 AM »
I figured this deserved a bump based on the findings from a recent conference in Montreal, Canada at McGill University. Looks like removing debris is on the table!

It's been on the table for a while now - but the problem is that nobody will spend the money it takes to get it off the table and into action...

Offline soldeed

  • Member
  • Full Member
  • **
  • Posts: 213
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #106 on: 05/13/2009 04:03 AM »
One factor making the problem worse presently is the unusually long solar minimum we are experiencing. 

http://www.nasa.gov/topics/solarsystem/features/solar_minimum09.html

When solar activity is high and there are a lot of sunspots and flares, this causes the atmosphere to expand and increase drag on orbiting objects.

It was recently asked of the hubble team why the telescope was not being re-boosted to which they replied that since solar activity has been so low that it did not need to be reboosted

Maybe we should try to provoke the sun! ;D
The Exodus is behind schedule

Offline bolun

  • Senior Member
  • *****
  • Posts: 2829
  • Europe
  • Liked: 241
  • Likes Given: 71
Re: Cleaning up near earth space
« Reply #107 on: 03/27/2010 06:38 PM »
Tiny cube to tackle space debris

UK researchers have developed a device to drag space debris out of orbit.

If successful, CubeSail could become a regular add-on system to satellites and rocket stages.

http://news.bbc.co.uk/2/hi/science/nature/8590103.stm

Offline tamarack

  • Full Member
  • **
  • Posts: 275
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #108 on: 03/28/2010 05:28 AM »
Tiny cube to tackle space debris
UK researchers have developed a device to drag space debris out of orbit.
If successful, CubeSail could become a regular add-on system to satellites and rocket stages.
http://news.bbc.co.uk/2/hi/science/nature/8590103.stm

What orbits will this be used in? I'd guess high inclination LEO and GTO.

Offline Velomir

  • Member
  • Member
  • Posts: 65
  • Warsaw, Poland
    • Kosmonauta.net - Polish space news and consulting site
  • Liked: 6
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #109 on: 03/29/2010 12:29 AM »
Actually such a concept will be tested by Poland's first satellite PW-Sat
This cubesat is due to launch on the first Vega flight
--
Blue Dot Solutions

Offline DeanG1967

  • Member
  • Full Member
  • *
  • Posts: 149
  • Liked: 20
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #110 on: 03/29/2010 03:59 AM »
Wait!  Wait!  I got it.  Ok, sell the Ares MLP for 200M (cheap) and then use the money to put Hoover Vacumns on contract.  They can build a self propelled space vacumn that can suck up all the space debree.  I mean it should be cheap...doesn't need a heppa filter or anything.

Thoughts?
« Last Edit: 03/29/2010 04:00 AM by DeanG1967 »

Offline tamarack

  • Full Member
  • **
  • Posts: 275
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #111 on: 03/29/2010 05:03 AM »
Wait!  Wait!  I got it. ... Thoughts?
A vacuum in a vacuum? If that's not sarcasm, someone should slap some sense into you.

Offline glanmor05

  • BWFC Fan
  • Full Member
  • ****
  • Posts: 434
  • It's not all tea and medals!
  • Blackpool, England
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #112 on: 03/29/2010 11:13 AM »
Tiny cube to tackle space debris

UK researchers have developed a device to drag space debris out of orbit.

If successful, CubeSail could become a regular add-on system to satellites and rocket stages.

http://news.bbc.co.uk/2/hi/science/nature/8590103.stm

How will they control where the stuff comes down and who do I sue when it hits my conservatory?
"Through struggles, to the stars."

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9173
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 623
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #113 on: 03/29/2010 04:04 PM »
If you could develop some kind of an unmanned craft which could reliably fly around and retrieve some of this larger stuff, would it make sense to ship it to the Moon for one's ISRU plant, as feeder stock?  How many tons of stuff is there?  It represents a lot of delta-vee investment in getting to LEO or GEO so some of the heavy lifting is done already.  Plus, would the owners object if you went up there and just took it?  I would go for the stuff that has a catalogued orbit first.

About zapping it with a laser.  The obvious showstopping problem is who'sa usin' da laser?  And whuffo, exactly?  Remember the uproar when the Chinese painted one of our sats with a laser?  If that's not a convincing argument about that particular solution, then what could be?

...
(1) Given a sufficiently large aperture, the same. You only get significant attenuation in the atmosphere.

(2) The attenuation depends very much on the angle of the laser relative to the vertical. A laser fired almost horizontally would be attenuated very much. Firing straight up would be best for attenuation, but that would be useless for decelerating the debris.

(3) In any case, the attenuation is not the real problem since it is only a few percent. The biggest problem is that the refraction index of the air varies over space and time, so the ray gets diverted in a random direction by a tiny amount. The same effect is responsible for the "flickering" of stars.

(4)You can avoid this to a large degree by choosing a site with good seeing, and compensate for the remaining fluctuations by using adaptive optics. This is almost exactly the same technology used by large ground-based optical telescopes.

Now I'm not an expert either, but you seem to be making better arguments against the idea than for the idea:

(1) How big do you suppose the "aperture" should be?  And the power requirements?  Hundreds of kilometers?

(2) Firing straight up, or within a narrow cone of vision, limits the volume of the space you affect by this method.  That the effect would not decelerate the debris, prompts one to ask, what exactly do you propose to do with the debris?  Vaporize it?

(3) Which gets back to the power requirements again, as well as attenuation and mode of operation, since clouds, birds, and airplanes are also involved in the calculations, as well as a considerable amount of atmosphere and assorted particulate matter.

(4) Suggest a site.  Chimborazo, in Ecuador, is already the site of "my" MagLev launcher.  The adaptive optics you refer to are receiving faint starlight, not transmitting the power levels necessary for such a laser as you might be thinking.

Don't litter.

...
Depends on what you define as reasonable...

That is a cop-out answer.  And as to the idea that it is too late to stop littering, that is simply not true.

Hey.  I'm part of the solution here...  But I do like the term "fliply snarky".

This is such a great site.  I can't wait to get the Orbital Debris Quarterly News.  I wonder what will be this quarter's centerfold?  I hear it's quite the T&A magazine.  That would be Titanium and Aluminum.  Sorry, you have to be fliply snarky first, then you can use "fliply snarky" in a sentence.  To show that you understand...

And William.  There has been some information already released about those birds ingested by airplanes.
« Last Edit: 03/29/2010 04:04 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5595
  • Liked: 1142
  • Likes Given: 684
Re: Cleaning up near earth space
« Reply #114 on: 03/29/2010 11:21 PM »
What orbits will this be used in? I'd guess high inclination LEO and GTO.

Why high-inclination orbits?

I would expect it to work well only in low orbits (regardless of inclination).  In GTO, the drag would be significant only at perigee, meaning that over time the apogee will gradually decrease.  Since apogee in GTO is so large, it will take a while to get the apogee down to the point at which there is significant drag over a large fraction of the orbit.

One worry I have is about the debris that may be generated by the sail itself.  It's a 25-square-meter target, which is pretty big.  Hopefully the sail is so thin that debris striking it does not generate more debris.  Or maybe the idea is that the sail de-orbits so quickly that there is not time to generate much debris.

Offline tamarack

  • Full Member
  • **
  • Posts: 275
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #115 on: 03/30/2010 01:01 AM »
What orbits will this be used in? I'd guess high inclination LEO and GTO.
Why high-inclination orbits?

I would expect it to work well only in low orbits (regardless of inclination).  In GTO, the drag would be significant only at perigee, meaning that over time the apogee will gradually decrease.  Since apogee in GTO is so large, it will take a while to get the apogee down to the point at which there is significant drag over a large fraction of the orbit. ...

I mentioned high-inclination LEO and GTO because they pose the greatest risk of high speed collisions and cascading debris as they cross orbits. High inclination is not only high risk, but the most crowded.
"The estimated mass of man-made objects within 2000 km of the Earth's surface is about 2,000,000 kg. These objects are mostly in high-inclination orbits and pass one another at an average relative velocity of 10 km/sec (about 22,000 mph). Most of this mass is contained in about 3000 spent rocket stages, inactive satellites, and a comparatively few active satellites. A smaller amount of mass, about 40,000 kg, is in the remaining 4000 objects ...(that)... are the result of over 115 on-orbit fragmentations and 20 anomalous events in which objects seperated from spacecraft but the parent body remains intact ..."
IADC - Interagency Report on Orbital Debris; 1995 (7.3MB)
http://www.iadc-online.org/index.cgi?item=documents

Equitorial GEO and LEO is less of a risk as collision speeds are significantly slower, easily predicted and collision debris would degrade rapidly. As to GTO; Most objects have a perigree of only a few hundred km and would be effected most by increased drag. They, and the dense debris field between 750-1000km, is what this device is likely made for.

I do question the effectiveness above 1000km, as there's another spike at 1500km and doesn't taper off until 6000, but I suppose this was designed for only the immediate concerns. The major problem I see, like glanmor05's, is the uncontrolled and unpredictable descent of these objetcs. It's very possibly that, if reckless, we could turn LEO into a disaster zone for a couple years with this technology.

Offline DeanG1967

  • Member
  • Full Member
  • *
  • Posts: 149
  • Liked: 20
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #116 on: 03/30/2010 02:14 AM »
Wait!  Wait!  I got it. ... Thoughts?
A vacuum in a vacuum? If that's not sarcasm, someone should slap some sense into you.

1.  Yes it was sarcasm

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5595
  • Liked: 1142
  • Likes Given: 684
Re: Cleaning up near earth space
« Reply #117 on: 03/30/2010 03:50 AM »
I mentioned high-inclination LEO and GTO because they pose the greatest risk of high speed collisions and cascading debris as they cross orbits. High inclination is not only high risk, but the most crowded.

Got it (I think): you're talking about where this device is most needed; I was thinking about where it would be most capable.

Quote
As to GTO; Most objects have a perigree of only a few hundred km and would be effected most by increased drag. They, and the dense debris field between 750-1000km, is what this device is likely made for.

My point is that slowing a spacecraft at perigee, which is what the sail does for something in GTO, lowers not its perigee but its apogee.  To lower the perigee, you need to slow down while at apogee; the sail cannot do that.

Offline bolun

  • Senior Member
  • *****
  • Posts: 2829
  • Europe
  • Liked: 241
  • Likes Given: 71
Re: Cleaning up near earth space
« Reply #118 on: 03/31/2010 07:59 PM »
Tiny cube to tackle space debris
UK researchers have developed a device to drag space debris out of orbit.
If successful, CubeSail could become a regular add-on system to satellites and rocket stages.
http://news.bbc.co.uk/2/hi/science/nature/8590103.stm

What orbits will this be used in? I'd guess high inclination LEO and GTO.

For debris in low Earth orbit, the sail will be angled so that residual air particles in the upper atmosphere slow it down, causing it to lose altitude. For higher debris, the sail will be pointed towards the sun, and pushed along by solar radiation.

http://www.guardian.co.uk/science/2010/mar/26/space-sail-orbit-debris

Offline bolun

  • Senior Member
  • *****
  • Posts: 2829
  • Europe
  • Liked: 241
  • Likes Given: 71
Re: Cleaning up near earth space
« Reply #119 on: 03/31/2010 08:20 PM »
Actually such a concept will be tested by Poland's first satellite PW-Sat
This cubesat is due to launch on the first Vega flight

Probably before the other Cube Sail

http://www.pw-sat.pl/

http://forum.nasaspaceflight.com/index.php?topic=6076.msg391953#msg391953


Offline Proponent

  • Senior Member
  • *****
  • Posts: 5595
  • Liked: 1142
  • Likes Given: 684
Re: Cleaning up near earth space
« Reply #120 on: 04/01/2010 12:33 AM »
For higher debris, the sail will be pointed towards the sun, and pushed along by solar radiation.

Ah, radiation pressure.  Hadn't thought of that; thanks for setting me straight.

I'm still wondering about the potential for the 25-square-meter to generate debris of its own.

Offline tamarack

  • Full Member
  • **
  • Posts: 275
  • Liked: 0
  • Likes Given: 0
Re: Cleaning up near earth space
« Reply #121 on: 04/01/2010 03:17 AM »
What orbits will this be used in? I'd guess high inclination LEO and GTO.
For debris in low Earth orbit, the sail will be angled so that residual air particles in the upper atmosphere slow it down, causing it to lose altitude. For higher debris, the sail will be pointed towards the sun, and pushed along by solar radiation.

http://www.guardian.co.uk/science/2010/mar/26/space-sail-orbit-debris

Interesting. For higher debris, would one side of the sail reflect, and the other absorb solar radiation to degrade the orbit? Rather than make the orbit elliptical with two reflective sides, bringing the perigree into the atmopshere for decay (which would likely take longer than the sail would last). Any clarification?
« Last Edit: 04/01/2010 03:20 AM by tamarack »

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4417
  • Liked: 189
  • Likes Given: 382
Re: Cleaning up near earth space
« Reply #122 on: 04/01/2010 04:07 AM »
Actually such a concept will be tested by Poland's first satellite PW-Sat
This cubesat is due to launch on the first Vega flight

I kinda wish they would quit putting this experiment on prototype rockets and just have it launched as a secondary payload on an EELV.

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5595
  • Liked: 1142
  • Likes Given: 684
Re: Cleaning up near earth space
« Reply #123 on: 04/01/2010 10:13 AM »
For higher debris, would one side of the sail reflect, and the other absorb solar radiation to degrade the orbit? Rather than make the orbit elliptical with two reflective sides, bringing the perigree into the atmopshere for decay (which would likely take longer than the sail would last). Any clarification?

A more effective strategy would be to turn the sail edge on to the sun at times when you don't want light pressure.  An absorbing sail will still tend to produce thrust, though less than a reflecting sail.  Exactly how much thrust depends on the details of how the sail cools, since the cooling radiation also produces thrust.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8654
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1124
  • Likes Given: 244
Re: Cleaning up near earth space
« Reply #124 on: 07/16/2010 12:04 PM »
Bad news for natural cleaning of LEO, the upper atmosphere collapsed to it's lowest levels in the recorded history of space flight due to the extreme solar min.

http://science.nasa.gov/science-news/science-at-nasa/2010/15jul_thermosphere/

If you're happy and you know it,
It's your med's!

Offline Space Pete

Re: Cleaning up near earth space
« Reply #125 on: 08/16/2010 01:34 PM »
China Top of Orbital Garbage Heap, Study Shows.
http://news.discovery.com/space/china-top-of-orbital-garbage-heap-study-shows.html

Giant Nets Could Some Day Capture Space Trash.
www.pcworld.com/article/203263/giant_nets_could_some_day_capture_space_trash.html

Giant nets could remove orbiting space junk.
www.physorg.com/news201229702.html
« Last Edit: 08/17/2010 04:36 PM by Space Pete »
NASASpaceflight ISS Editor

Offline Space Pete

Re: Cleaning up near earth space
« Reply #126 on: 09/03/2010 09:12 PM »
Russian Physicists Developed Space Debris Tracker.

A group of scientists from Lebedev Physical Institute (FIAN) have developed a unique special tracker and SW which can be used to search for small space debris from 1 to 10 cm.
Space debris problem is rather critical today, as there are about 100 thousand debris of non-operational spacecraft, parts of upper stages, bolts, nuts, etc. are in orbit. However even a 1 cm object can impose serious damage for a satellite.
To search for debris, Russian scientist propose to use a refractor with an input eye of 50 mm. It can see debris at range of several hundreds of kilometers, and could be installed on any spacecraft.
Special SW helps the tracker to recognize space debris. The tracker is also capable of defining orientation of the carrier-spacecraft.
FIAN proposes to install the tracker on the spacecraft intended for 600-800 km orbits, or GSO, for which the space debris problem is the most actual.
The opportunity to install FIAN's trackers on some Russian satellites is under discussion, RIA Novosti informs.

Source.
NASASpaceflight ISS Editor

Offline jimgagnon

  • Full Member
  • ****
  • Posts: 610
  • Liked: 0
  • Likes Given: 1
Re: Cleaning up near earth space
« Reply #127 on: 11/27/2010 04:52 PM »
Russia To Spend 2 Bln Dollars For Space Clean-Up

"Russia's Rocket and Space Corporation Energia announced Tuesday that it will build a special orbital pod designed for sweeping-up the near-Earth space from satellite debris."

http://www.spacedaily.com/reports/Russia_To_Spend_2_Bln_Dollars_For_Space_Clean_Up_999.html

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32479
  • Cape Canaveral Spaceport
  • Liked: 11258
  • Likes Given: 333
Re: Cleaning up near earth space
« Reply #128 on: 11/27/2010 04:54 PM »
Russia To Spend 2 Bln Dollars For Space Clean-Up

"Russia's Rocket and Space Corporation Energia announced Tuesday that it will build a special orbital pod designed for sweeping-up the near-Earth space from satellite debris."

http://www.spacedaily.com/reports/Russia_To_Spend_2_Bln_Dollars_For_Space_Clean_Up_999.html

Not believable.  They don't have the money

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8654
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1124
  • Likes Given: 244
Re: Cleaning up near earth space
« Reply #129 on: 11/27/2010 05:31 PM »
More interesting it will be nuclear powered and dump some 600+ GEO derelicts into the ocean. That is quite th DeltaV...
If you're happy and you know it,
It's your med's!

Offline savuporo

  • Senior Member
  • *****
  • Posts: 5155
  • Liked: 985
  • Likes Given: 343
Re: Cleaning up near earth space
« Reply #130 on: 11/27/2010 05:48 PM »
Not sure if Joe Carroll's EDDE was in this thread yet ?
He did a presentation on this recently on SSI Space Manufacturing 14 conference, and made a case for collecting LEO aluminium "scrap" as the first in situ space resource to be utilized.

http://www.amostech.com/TechnicalPapers/2010/Posters/Levin.pdf
« Last Edit: 11/27/2010 05:49 PM by savuporo »
Orion - the first and only manned not-too-deep-space craft

Tags: