SailNet Community banner

1 - 20 of 33 Posts

·
Registered
Joined
·
3,336 Posts
Discussion Starter #1
Wondering if we may want to dust off our sextants in the coming months and years. A derelict Russian satellite and a functioning American satellite collided a few days ago, creating a debris field 500 miles above the earth. Apparently this is a popular orbit for the satellites that give sailors, airmen and drivers coordinates for our navigational devices. Once you have a collision like this, it's like a chain reaction, causing more collisions and more debris, so on and so forth. And it apparently takes a little time for gravity to clean up the mess (10,000 years, according to some sources). I'm wondering when space is going to be all but inaccessible to us...

Read it and weep:

Space crash debris to orbit Earth for 10,000 years - Yahoo! News
 

·
Registered
Joined
·
5,491 Posts
Well, this is why I keep up my CN, not because I'm a Luddite, but because I understand physics and probability.

Kessler Syndrome - Wikipedia, the free encyclopedia

From a launch perspective, a thin, wildly dispersed field of coin-sized spalls is much worse than chunks of dead satellites here and there. It's like dioxin: a barrel of the stuff in one place is bad enough, but a few micrograms in everybody is deadly.
 

·
Registered
Joined
·
3,336 Posts
Discussion Starter #3
I didn't realize there was a name for the phenomenon. Looks like we'll be kissing the blessing of satellite technology goodbye in the near future. Goodbye Captain Garmin, hello Captain Cook! Seems inevitable at this point.
 

·
Registered
Joined
·
5,491 Posts
Maybe not, but the phrases "clear and present danger" and "law of unintended consequences" come to mind.

Space is very, very big, but time is very, very long. See "what was that container doing there?" for the yachting equivalent.

Anyone who's evolved on a planet like this one that's had two and possibly more major extinction events due to fairly modest space rocks slamming into us with gigatons of TNT equivalent explosive power has no right to be smug about the rapidly moving crap they've left in a can't decay fast enough orbit.
 

·
Registered
Joined
·
5,491 Posts
Well, he's been a little on edge lately as it is...

My wife starts her celestial navigation course on the 17th. This is purely coincidental. I took mine four years ago.

Can't hurt, might help, certainly improves the navigation, and a sextant is a precision instrument. A man can't have too many of those.
 

·
Registered
Joined
·
3,070 Posts
You have to remember that the GPS Satellites are 11000 miles above the earth. The debris field should not be of any worry. Unless that debris is flung outwards toward the GPS orbits. Then you can worry abit about it.
 

·
Grasshopper
Joined
·
908 Posts
You have to remember that the GPS Satellites are 11000 miles above the earth. The debris field should not be of any worry. Unless that debris is flung outwards toward the GPS orbits. Then you can worry abit about it.
and the US and Russian communications satellites that collided were about 500 miles above Earth.
 

·
Registered
Joined
·
5,491 Posts
True, but the intervening space between LEO and HEO can be covered by flying debris in under an hour...heh heh.

Seriously, it's not the satellites in HEO I worry about, but the fact that they eventually fail or otherwise go out of service. If a thin layer of debris exists between the surface of the Earth and that altitude, for lack of a better term, and the debris is randomly moving at 10X bullet speed, the problem becomes "how do you fly a great big rocket full of rocket fuel through that to reach high orbit?"

The situation is analogous to motoring through the Great Pacific Gyre without trapping a plastic bag against your raw water intake. The ocean is very big, but the plastic bits and pieces in the water column are numerous and randomizes once inside the gyre.
 

·
Registered
Joined
·
3,336 Posts
Discussion Starter #10
and the US and Russian communications satellites that collided were about 500 miles above Earth.
The problem as I understand it is that high earth orbit will eventually become inaccessible due to the space debris in low earth orbit. Once these global positioning satellites come to the end of their working lives, we won't be able to get one through the gauntlet.
 

·
Banned
Joined
·
711 Posts
But....but...but

I thought GPS couldn't be threatened. I thought it was impervious to attack. I thought we didn't need all that antiquated, old school, neanderthal-era navigation stuff. Glad I saved the Loran and sextant. All this time, the Chinese were the concern, and look, it's just an accident that's showing how vulnerable the whole deal could be. Well, they say it was an accident. Maybe the Ruskies did it on purpose. OOOoohhhhh!!!! ...........
 

·
Registered
Joined
·
286 Posts
From what I understand, the U.S satellite that was destroyed was an Iridium communications satellite. I wonder what effect this will have on the reliability of the Iridium system?
 

·
Registered
Joined
·
239 Posts
They will just move one of their "in orbit" spares to fill the gap. There was a press release about some small issues, and about it taking a month to move the spare in to replace it.
 

·
Grasshopper
Joined
·
908 Posts
Maybe it's time for NASA to develop a giant vacuum space craft, or have the guys in the space shuttle pick up a little trash on each trip.:p
 

·
Registered
Joined
·
5,491 Posts
Funny, that's not what I got from the report to Congress here:

http://pnt.gov/public/docs/2008-biennial.pdf

It seems at least vulnerable, if not marginal. Anyway, my point is this: the prudent mariner relies on a suite of navigational aids, and that GPS is only one. It is a very good one, admittedly, but there are shortcomings to it due to the nature of space itself.

I suspect the best course would be to get a GPS receiver that can receive ALL the "constellations" either in use now or shortly to be in use. Seamless switching from the U.S. system to the European Galileos to GLONASS to COMPASS...whatever. This would greatly reduce the chance of outages in service or coverage for the average boater.
 

·
Registered
Joined
·
2,705 Posts
Question and answer time

Q) What is the longest single voyage I'm likely to do?

A) Probably 4 weeks at sea.

Q) How many satellites does my GPS log onto at any one time?

A) Mmmmm - normally 9, sometimes 11

Q) How many does it need to give me a fix?

A) I think it's 3

Q) What are the chances of any 6 satellites getting taken out by space debris in four weeks?

A) Very, very remote.

Q) What are the chances that all 6 will be in my sector of the sky?

A) None at all.

Q) Should I be worried?

A) I don't think so.
 

·
Registered
Joined
·
34 Posts
Being a plumber and knowing how much I get for scrap metal I would suggest in the not so distant future when space travel is more the norm the returning space ship's could do what the early sailing ship's did in a Australia we'd send our WOOL to England and they'd return to Sydney full of what ever the colony needed Iron roofing etc the returning ship's could return full of space junk ready to be recycled its just a thought cheers Kerry
 
1 - 20 of 33 Posts
Top