More space debris

[bdewoody]

How long will it be until man made space junk resulting from satellite collisions makes manned orbital space flight too dangerous to attempt. At space.com there is a story postulating that a retired satellite (UARS) has broken up after a collision with a piece of junk from an earlier accident. Seems to me that things could snowball until we can't safely orbit the earth.<br /><br />Maybe it's time to come up with a way to do some spring cleaning up there. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[jsmoody]

I'm not sure it's feasable to do any cleaning up, but there are international laws now about launching new satellites, you have to include the ability to move it into position so that it will burn up in the atmosphere after it's useful lifespan is over. That's a good step, but not a permanent solution. <div class="Discussion_UserSignature"> No amount of belief makes something a fact" - James Randi </div>

 

[bobblebob]

Ive thought this for some time now. There might be alot of 'space' out their, but we're quickly populating it with satellite's that take years to fall back to earth and break up <br /><br />Interestingly how many satellites (current or ones that have been retired) are currently orbiting earth?

 

[willpittenger]

Sigh. Too bad we can't just build vacuum cleaners that work in Space. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[kelvinzero]

How about a broom?<br /><br />http://en.wikipedia.org/wiki/Laser_broom<br /><br />It does not necessarily need to vaporise the entire object. It could use ablation to slow the object down into a safer orbit.

 

[holmec]

how about using the asteroid gravity tug technique on space debris? do passes on the debris causing it to slow or be deflected in its orbit so they come down and burn up in the atmosphere. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[cbased]

<i>Interestingly how many satellites (current or ones that have been retired) are currently orbiting earth? </i><br /><br />I only have info about the ones that are beyond Earth orbit:<br />http://www.johnstonsarchive.net/astro/awrjp493.html<br /><br />I guess these are too many pieces on Earth's orbit for someone to list them?<br />

 

[bobblebob]

Thanks <img src="/images/icons/smile.gif" /><br /><br />Wow, if that many are beyond Earth orbit, how many are actually in Earth orbit <img src="/images/icons/blush.gif" />

 

[itsfullofstars]

Early 2007 the number of trackable objects (over 4 inch) came to 10,000. <br /><br />After the china anti satellite test there were another 900 trackable objects.<br /><br />The china test may have created 35,000 smaller objects of 1cm to 4 inch. In other words 35,000 speeding bullets and shells.<br /><br />Some estimates I have read in the past put the number of 1cm and above objects at 600,000 and then you have all your tiny paint chips and splinters each capable of taking out a satellite.<br /><br />Scientists are now starting to mumble about approaching critical mass and chain reactions that could take out most if not all of our on orbit communication infrastructure. Not only that but the inability to launch anything else including exploration missions.<br /><br />The whole problem is getting quite scary, yeah we might be developing the technology to take out approaching asteroids but will we be able to launch the thing without it being blown to bits by space junk?<br /><br />Here are a couple of links with numbers, I don’t know where I read it all tho.<br /><br />http://www.space.com/news/070202_china_spacedebris.html<br /><br />http://www.nytimes.com/2007/02/06/science/space/06orbi.html<br /><br />And a nice interactive space junk map here.<br /><br />http://www.nytimes.com/2007/02/06/science/20070206_ORBIT_GRAPHIC.html<br /><br />Wherever man goes you will find empty cans and other assorted litter, god we are mucky b***gers!!<br /><br /><br />

 

[itsfullofstars]

By the year 2000 there had been roughly 5,000 recorded satellite launches. Only maybe 700 of those are still active.<br /><br />So that means 4,300 have either been de-orbited, blown to bits or are just floating about. Lovely!! pity we cant all go up there with those pointy sticks and a big bin bag!!<br /><br />Another link for you.<br /><br />http://www.aiaa.org/aerospace/Article.cfm?issuetocid=122&ArchiveIssueID=17 <br />

 

[bobblebob]

That really is quite scary reading some of them links, and the graphic of what space junk is out there. <br /><br />Regarding this international law about new satellites having to include the ability to move it into position so that it will burn up in the atmosphere. Do the new satellites have a time limit from when they are non-operational to when they have to burn up upon reentry?

 

[itsfullofstars]

"Do the new satellites have a time limit from when they are non-operational to when they have to burn up upon reentry?"<br /><br />I havent read anything about that but it is a good idea.<br /><br />You can read a little bit about the new (I say new, this is from 2004) satellite rules here.<br /><br />http://www.gsblaw.com/resource/pub_result.asp?ID=1811316272006<br /><br />I also found some more numbers, if you are interested, here....<br /><br />http://celestrak.com/satcat/sources.asp<br /><br />And the prizes for current on orbit debris go to……….<br /><br />1st Place: USA<br />2nd Place: Peoples republic of China<br />3rd place: Commonwealth of Independent States (former USSR)<br /><br />USSR were the biggest offenders but most of their debris has re-entered.<br /><br />The above site lists current on obit payloads (full intact satellites) as 3,228<br />

 

[bobblebob]

Thanks for the links <img src="/images/icons/smile.gif" />

 

[qso1]

holmec:<br />how about using the asteroid gravity tug technique on space debris? do passes on the debris causing it to slow or be deflected in its orbit so they come down and burn up in the atmosphere.<br /><br />Me:<br />AFAIK, this technique does not work on a practical scale on objects with mass values as small as satellites. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[bdewoody]

Would using our newly developed laser cannon make the situation better or worse? <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[scottb50]

I would think breaking thousands of pieces of debris into millions of pieces would not be a very good idea. <div class="Discussion_UserSignature"> </div>

 

[kelvinzero]

See the link I posted above. Does anyone know what happened to that laser broom project?

 

[scottb50]

I did. I would think ablating a surface would generate quit a bit of debris. The smaller the particles the better, but as mentioned it would act like a sandblaster, eroding exposed surfaces. Probably not as bad as being smacked by a piece of debris but eventually it would cause wear, not to mention the effect on optics. <div class="Discussion_UserSignature"> </div>

 

[j05h]

The "Project Orion" laser was just a concept or feasibility study, IIRC. It showed great promise using fairly simple lasers. The residue left over was managable while significantly reducing large-scale debris. It promised to remove, over the course of years, all the significant debris in LEO. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[scottb50]

If you reduce the size of the material it seems to me it would be less likely to fall out of orbit naturally. A ten pound chunk of metal would be affected more by gravity and molecular impacts than a cloud of minute particles. Also much less to be trackable and avoidable. <div class="Discussion_UserSignature"> </div>

 

[kelvinzero]

large or small objects act identically under gravity. <br /><br />However there is a very slight drag in low orbit from the very thin atmosphere, which I assume affects small objects much more than large ones due to having much higher ratio of surface area to mass. This is why a feather falls slower than a bowling ball. On the moon they would fall at identical rates.

 

[scottb50]

It's more the feather has less surface area to be affected not the size. Even on the moon the feather would land sooner, though it would be a minute difference. The rate would be the same but the effect of what little atmosphere exists would affect the feather, because of it's much greater surface area, then the bowling ball, because of it's more aerodynamic shape.<br /><br />If you look at that in reference to particles, or small bits of matter they would have much less interaction with random molecules. If you drop a feather or a flat plate, of the same mass and shape, it would reach the surface sooner because it would interact with more molecules. <div class="Discussion_UserSignature"> </div>

 

[bdewoody]

Ah, you forget Galileo's famous experiment. Gravity has the same effect on objects of all masses. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[MeteorWayne]

Actually, he said the feather would land sooner, but there are several competing concepts. Straight drop vs orbit.<br />An orbiting feather would land sooner, a dropped feather would land later, assuming the moon's atmosphere is thick enough to have any effect at all. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[j05h]

<i>> If you reduce the size of the material it seems to me it would be less likely to fall out of orbit naturally. A ten pound chunk of metal would be affected more by gravity and molecular impacts than a cloud of minute particles. Also much less to be trackable and avoidable.</i><br /><br />As others point out, gravity affects the objects the same. The "Orion" laser would impart random delta-V on the objects, perturbing their orbits and causing them to deorbit much faster than otherwise. It would not break objects apart generally, but would heat them. It's similar in concept to the Mirabo Lightship laser-propulsion, except used for cleanup.<br /><br />I don't remember if the Orion laser would work on small particles/flakes of material. I do remember that they claimed significant reductions in larger, dangerous space debris like bolts, dropped wrenches and parts of exploded uppper stages. Basically all the stuff that NORAD tracks for potential impacts.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>