posted 09-05-2009 03:35 AM               

When one reads of this in the media they always talk in terms of speeds of thousands of miles an hour. But is this really the case?

All(?) satellites are launched west-east to some degree to take advantage of the Earth's rotation with this factor being greatest for equatorial orbits and lessening the closer one gets to polar orbit. Therefore, is it not the true that any collisions between space debris will be between pieces travelling in roughly the same direction? And, will not the highest impact speed be between a piece in polar orbit meeting a piece in equatorial orbit?

Therefore, it follows does it not, that impact speeds will range from a few tens of miles per hour to perhaps hundreds at the most? This is to say the orbital speed component is taken out of the equation so that the impact speed is simply the overtaking or being overtaken speed.

Am I wrong? Can anyone do the sums and come up with a rough answer? My guess is that it will not be anything like the media say it would be.

posted 09-05-2009 06:45 AM               

1. Not all launches are eastward (Prograde); Some satellites are placed in an opposite (Retrograde orbit) depending on the intended application of the payload.

2. Orbit convergence between two objects which were initially launched in the same general direction can result in significantly different velocity vectors depending on their respective orbit inclinations (angle of orbit with respect to the equator), orbital eccentricity (shape of the orbit). Objects can converge at high rates of speed even if they are on the same inclination but one is traveling its ascending leg (i.e. northward) while the other is on a descending leg (southward). Closing speeds on the order of 15-20 thousand miles per hour in this case are not unusual, particularly for two object occupying highly inclined and/or eccentric orbits.

posted 09-06-2009 12:53 AM            

The 2 satellites traveling at nearly 22,000 mph less than 500 miles above the Earth struck one another at a 90-degree angle, and created quite a mess.

There was another presentation from a Russian gentleman Vladimir Agapov, entitled Analysis of the Prediction Characteristics for the Collision.

Some very interesting facts and revelations.

Much of that debris will be orbiting the earth anywhere from the next 25 years to the next 100 years.

As the meeting was going on, we were informed that a piece of a rogue rocket motor was heading towards the ISS.

There is so much debris up there right now, that it is almost unimaginable.

You think 'space' is a pretty big area?

When you see the animation that is available by a company called AGI, they create analysis software for space situational awareness, you get to see how small 'space' really is.

Image courtesy of Analytical Graphics, Inc.

There were discussions about creating some sort of a "Traffic Control Organization for Space Debris". How bad is that?

Everybody and their uncles are sending rockets/payloads into space.

The week was filled with tons of technological facts and information: iPods with GPS, now you can even get a program on it that will tell you what constellation in the sky you are looking at by just holding your iPod up to the heavens.

posted 09-06-2009 09:07 AM               

quote:

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Originally posted by Rizz:
The 2 satellites traveling at nearly 22,000 mph less than 500 miles above the Earth struck one another at a 90-degree angle, and created quite a mess.

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posted 09-11-2009 07:55 AM               

quote:

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Originally posted by Rizz:
Pretty soon you'll be able to launch a rocket with your iPod.

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