[kenrexford]

Not sure what this is all about, but I just saw that a US "communications satellite" "crashed" with a russian "communication satellite."

Hmmmm.

Is this one of those things we hear about initially as one thing but know that our grandchildren will study later as something entirely different?

[PassedOut]

Scientists aware satellite paths would be close

Quote

PARIS, Feb 12 (Reuters) - European space scientists were aware of the potential for a close encounter between Russian and U.S. satellites before they crashed.

But the difficulty of predicting orbits and "noise" from thousands of pieces of debris made a definitive prediction of a collision impossible.

Someday there will be a great business opportunity involving cleaning up all the space debris up there.

[mike777]

My first thought is, was this done on purpose?

[Winstonm]

mike777, on Feb 12 2009, 02:59 PM, said:

My first thought is, was this done on purpose?

This sounds like the work of Dr. Evil!

[Al_U_Card]

I wonder what the calculated odds are of a collision between two such tiny devices in such vastness? Shared orbits are one thing, collisions another. As the debris should not "slow" down, only those parts that were "thrown" into a lower orbit may cause a problem for the ISS.

[Echognome]

Al_U_Card, on Feb 12 2009, 01:36 PM, said:

I wonder what the calculated odds are of a collision between two such tiny devices in such vastness? Shared orbits are one thing, collisions another. As the debris should not "slow" down, only those parts that were "thrown" into a lower orbit may cause a problem for the ISS.

Probably quite low for any two particular objects. However:

Quote

At the beginning of this year, there were roughly 17,000 pieces of manmade debris orbiting Earth, according to NASA. The items, at least 4 inches (10 centimeters) in size, are being tracked by the U.S. Space Surveillance Network, which is operated by the military.

From: http://news.yahoo.com/s/ap/20090212/ap_on_...llite_collision

So the odds go up considerably that two objects would collide. Granted the things aren't random as they are sent out on particular orbits.

[Gerben42]

If there are 17,000 objects, that would mean you would have to track 289 million combinations to check for collisions.

What's more important: Which satellite had priority? In space there is no right or left!

[matmat]

Gerben42, on Feb 13 2009, 10:49 AM, said:

If there are 17,000 objects, that would mean you would have to track 289 million combinations to check for collisions.

What's more important: Which satellite had priority? In space there is no right or left!

clearly one of them ignored the stop sign.

need the space police to step in and sort this mess out.

[mike777]

Funny enough the USA satellite claims it could have moved out of the way if Russian Cops or USA Cops had told her it was in danger but no one told her.

[barmar]

Gerben42, on Feb 13 2009, 10:49 AM, said:

If there are 17,000 objects, that would mean you would have to track 289 million combinations to check for collisions.

It's not nearly so bad, since the satellites aren't all in the same orbits. Satellites at different altitudes can't crash into each other. And satellites in geosynchronous orbits can only interact with satellites close by.

But I don't think you would actually track combinations anyway. You calculate the locations of all the objects, sort them by location, and then go through the list checking the distance between adjacent objects.

[hotShot]

Al_U_Card, on Feb 12 2009, 11:36 PM, said:

I wonder what the calculated odds are of a collision between two such tiny devices in such vastness?  Shared orbits are one thing, collisions another. As the debris should not "slow" down, only those parts that were "thrown" into a lower orbit may cause a problem for the ISS.

The debris does in fact slow down. The exosphere can expand up to over 6500 miles.
Of cause the process is very slow and gets even slower with the distance.
The new debris is only about 600 miles high, some day this debris will be slow enough to reach the hight of the ISS, probably the ISS vanished before that....

[PassedOut]

Here is another good project for international cooperation: Space Vacuums?

Quote

The United Nations has adopted voluntary guidelines to minimize the creation of new space debris. It recommends such steps as designing spacecraft so that no debris is released during normal operations, removing leftover propellants at the end of a mission and moving nonoperational satellites out of congested orbits. A U.N. meeting in Vienna this month will assess how well that effort is going. The looming problem yet to be addressed is how to get rid of the debris and objects already up there and proliferating with every collision.

Countries should contribute to the cleanup costs according to the amounts of space junk they've left.