Debris in earth orbit questions

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Profile Bob DeWoody
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Message 1666727 - Posted: 18 Apr 2015, 6:56:05 UTC

As I understand it the orbital speed of an object in orbit around a planet depends on it's speed. The faster the object is moving the higher it orbits until escape velocity is achieved. Also, most every satellite that has been put into orbit travels from west to east since the rotational speed of the earth provides some of the orbital speed. So most of the debris travels from west to east. And if an object is at the same altitude as a space craft or the ISS why isn't it's relative speed basically the same?
Bob DeWoody

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Profile Chris SCrowdfunding Project Donor
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Message 1666740 - Posted: 18 Apr 2015, 7:54:39 UTC

I thought that orbits decay over time. Every so often they have to lift the ISS higher up in its orbit.
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Profile William Rothamel
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Message 1666775 - Posted: 18 Apr 2015, 10:22:03 UTC - in response to Message 1666727.  

Pretty soon we will have enough debris in orbit to provide a sun shade to please all of the warmer apostles, devotees and prophets.
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Message 1666781 - Posted: 18 Apr 2015, 11:21:55 UTC

There are a number of issues with the debris field.
Yes the orbit of the junk does decay, now obviously that from higher orbits will gradually descend to lower orbits, but it its orbital path can change from a "nice circular" one to a more elliptical one, or its orbital inclination can change, as can its position with respect to the equator, any of these changes can bring it into conflict with a working satellite, or the ISS, or a craft on its way to/from the ISS...
The big stuff isn't too bad, its location and orbit is known, but much of the smaller stuff is lost to our eyes. To this end NASA, and probably the other space agencies, are spending shed loads of money in locating and plotting the debris.
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Profile Gary CharpentierCrowdfunding Project Donor
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Message 1666833 - Posted: 18 Apr 2015, 15:41:38 UTC - in response to Message 1666727.  

And if an object is at the same altitude as a space craft or the ISS why isn't it's relative speed basically the same?

Even if it is in a circular orbit it can approach from 90 degrees. But not all orbits are circles and not all stuff was sent up to go to the east. We have lots of polar orbits and all their debris would be in a polar orbit. Also anything that was sent higher may trail debris in some elliptical orbit that crosses the ISS. It can come from any direction.
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Message 1667003 - Posted: 18 Apr 2015, 21:06:00 UTC

Launching a rocket eastward certainly helps get it up to speed, but this ‘head start’ is only about 5% of a minimal orbital velocity. And, as implied by others’ comments, many satellites are steered into inclined orbits after an initial west-to-east boost phase. In remote-sensing applications e.g., polar orbits are particularly useful, allowing coverage of the entire globe—while a more-or-less equatorial orbit passes over a correspondingly narrow range of latitudes.

@Chris, absent friction and other extraneous forces, an orbit can maintain itself indefinitely without any expenditure of energy. The ISS changes altitude to avoid drag, keeping as low as possible but just above the atmosphere, which swells & shrinks in response to space-weather conditions. Since there’s no sharp cutoff, some compromise is involved, but I believe that the air-resistance it’s allowed to experience is pretty negligible.

Atmospheric drag tends to circularize eccentric orbits (until the final inward spiral begins). Surviving objects in elliptical orbits that barely avoid grazing the atmosphere will be near perigee while encountering a satellite in a circular LEO, so will be moving faster; even if their general directions are the same their closing speed can be quite high.
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Message 1667136 - Posted: 19 Apr 2015, 8:13:47 UTC

If I happen to know that there are satellites in orbit around the earth, this is because they have been placed there by means of a launch from the earth by means of a rocket.

So, even if such an object is circulating or orbiting the earth by means of a given speed, it might be considered as being a free-fall down to earth at the same time.

The speed such an object is having is not enough to escape the gravitational effects of the earth. Becaus of this, any object which are moving at a speed lesser than the one needed in order to escape the earth in the end will come back to the ground.

This is supposed to be happening all the time.
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Message 1673744 - Posted: 4 May 2015, 7:24:11 UTC

It's probably time to make a 'space Hoover' (vacuum cleaner) LOL
I'm not a complete idiot, but, I'm working on it.
I have an opinion and I'm not afraid to use it
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Profile Bob DeWoody
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Message 1673794 - Posted: 4 May 2015, 12:08:51 UTC

I read something last week about NASA may be ready to deploy a space laser to track and zap small pieces of space junk that are in orbit. But I can't remember the web page.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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KLiKProject Donor
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Message 1673798 - Posted: 4 May 2015, 12:29:10 UTC - in response to Message 1673794.  

I read something last week about NASA may be ready to deploy a space laser to track and zap small pieces of space junk that are in orbit. But I can't remember the web page.

or to pull them down with small nudge...so they can burn up in atmosphere...

yes, I've also read it...something about DARPA & NASA project... ;)

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Message 1673817 - Posted: 4 May 2015, 14:06:52 UTC
Last modified: 4 May 2015, 14:09:26 UTC

Lots of 'debris' in our planetary system...
For instance http://en.wikipedia.org/wiki/Cosmic_ray_visual_phenomena
But I said look here brother
Who you jiving with that cosmik debris?
Now who you jiving with that cosmik debris?
Look here brother, don't waste your time on me
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Message boards : Science (non-SETI) : Debris in earth orbit questions


 
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