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Fraser
2009-Nov-03, 10:50 PM
The U.S. Air Force began upgrading its ability to predict possible collisions in space after two satellites collided in February 2009, and has now done a collision analysis on over 800 maneuverable satellites. They hope to be able to track 500 more non-maneuvering satellites by year's end. But maneuverable satellites aren't the problem. [...]

More... (http://www.universetoday.com/2009/11/03/space-junk-threatens-future-missions/)

danscope
2009-Nov-03, 11:13 PM
Well, ....when you put 'that much stuff' into the same general orbit,
eventually it is going to get crouded.... even in space.

Dan

slang
2009-Nov-03, 11:19 PM
NASA publishes the Orbital Debris Quarterly News (http://www.orbitaldebris.jsc.nasa.gov/newsletter/newsletter.html). No easy subscription option... harsh* words shall be sent!

Does anyone here happen to work at Johnson, and be in a position to contact these people to ask them for an online subscription system, PDF in email, and perhaps an option to get a zipfile with old issues? I don't ask much, I know. :)

*) in the sense of grovelling, probably.

Hmm, online subscription found here (http://www.orbitaldebris.jsc.nasa.gov/newsletter/subscription.html). (The more visible link to subscribe leads here (http://www.orbitaldebris.jsc.nasa.gov/newsletter/sub_request_print.txt))

danscope
2009-Nov-04, 12:38 AM
Hi, Thanks for the link.

Best regards,
Dan

EricFD
2009-Nov-04, 02:55 AM
Well, ....when you put 'that much stuff' into the same general orbit,
eventually it is going to get crouded.... even in space.

Dan

Ditto! I'm surprised with that much stuff orbiting the Earth that there haven't been more collisions. And it didn't help that the Chinese deliberately destroyed a satellite thus creating even more debris. That was a real bright thing of them to do. Wasn't it?

Eric

danscope
2009-Nov-04, 03:07 AM
Yep, We need Jack Nicholson to tell them " Hey pal, hows about just giving your old satelites a push downward and let 'em burn up and just save us all
a lot of problems."
It could happen... :)

Dan

sexymaria_1984
2009-Nov-23, 05:21 PM
Yep, We need Jack Nicholson to tell them " Hey pal, hows about just giving your old satelites a push downward and let 'em burn up and just save us all
a lot of problems."
It could happen... :)

Dan

This kind of seems like common sense. Since everyone is beginning to realize that space junk is a problem, how about sending it all downward? That seems pretty open and shut. And yet, they don't do anything but complain about it being up there.

Stephanie

danscope
2009-Nov-23, 06:57 PM
Quite agree. Maybe the solution is to put a satelite in higher orbit, fitted out with a strong enough laser that it could actually repell selected targets and
drive it below it's orbit for eventual burnup. Some people talk about this technique for displacing meteorites. Why not apply it to space junk.
It goes up; it must come down.
......nah.....too simple . :)
And by the way, Welcome to the Baut forum. You shall converse with many excellent people here.
May we serve each other well.
Best regards,
Dan

JonClarke
2009-Nov-23, 08:46 PM
Ditto! I'm surprised with that much stuff orbiting the Earth that there haven't been more collisions. And it didn't help that the Chinese deliberately destroyed a satellite thus creating even more debris. That was a real bright thing of them to do.

It was even brighter that the US decided to do much the same thing.

swampyankee
2009-Nov-23, 09:00 PM
One pet peeve I have about many of the people who write or speak about space junk is that they always mention the dangers of the junk's high orbital velocity, which is, of course, not going to be the impact velocity, which will be the relative velocity between the two objects. It would be a rare collision where the relative velocities approach the bodies' orbital speeds.

antoniseb
2009-Nov-23, 09:39 PM
... the impact velocity, which will be the relative velocity between the two objects. It would be a rare collision where the relative velocities approach the bodies' orbital speeds.

If two objects are in nearly the same orbit, the impact velocity WILL be much lower. But, if you get polar orbit stuff hitting equatorial stuff, that will be pretty much an orbital velocity collision. Likewise If you have two things in orbits in any other high angle plane, like ISS orbit stuff colliding with things debris from almost anything else...

If you look at collision cross-sections most will be with relative velocities at least half of the orbital velocity.

Rhaedas
2009-Nov-23, 09:46 PM
You're right about the difference of velocities being the real problem, both in damage potential as well as detection and avoidance, but I wouldn't say high velocities are rare. It would be rare for debris to share a similar orbit and hit each other.

Wasn't the February collision at 90 degrees to each other?

And satellites are fragile to begin with, so do you really need a high difference to break a few things off, multiplying the debris field?

The biggest problem is the amount of space that some deorbiting mechanism would have to cover. Dan's idea of a higher orbiting energy weapon to slow the orbit sounds nice, but does this have the same problem as the whole Star Wars Defense, where locating, tracking, and hitting the target is beyond our capability? And we're talking for the most part much smaller targets than an ICBM.

publiusr
2009-Nov-23, 10:55 PM
Israel's sats have to be launched from East to West so the LVs can fall over water IIRC.

danscope
2009-Nov-24, 05:58 AM
Hi, I have no idea if such a scheme is practical. We do know that much of this orbital debris is watched. Well,....who knows. maybe someday.
Best regards,
Dan

Azza2111
2009-Nov-29, 09:59 PM
@swampyankee
If you look at ESA's space debris page, you will see that over time space debris tends to disperse itself over a large range of inclinations, RAANs and arguments, due to flattening etc. Now considering that LEO has the highest spacial density of any region and has the largest velocities, even a small inclination change results in a large change in relative vector velocities (a 90 degree relative difference in i, is the equivalent of one object striking the other at rest), and considering that the current multi-stage whipple shields can only stop something with the size of a 1cm diameter, think about all the parts on a satellite that exceed this.

I have a current listing of all the objects in LEO at the moment with their asociated RCS.and there are plenty exceding this.