Space Debris Hitting Calgary

[BlueGoblin]

I'm surprised that there wasn't more discussion of this in the media - A very large (described in media reports as the size of a school bus or pickup truck) chunk of Russian Rocket booster was very briefly set to strike Calgary on Friday morning. There was only a small amount of warning available from identification of the threat to the estimated time of impact. The booster fortunately ended up breaking apart and came down in the Atlantic Ocean.

That would have made one hell of a mess had it come down intact in or anywhere near the city...

http://www.cbc.ca/canada/calgary/story/2009/02/13/cgy-space-debris.html


http://news.sympatico.msn.ca/Video/Player.aspx?v=9191f66b-175c-40bd-97c2-df2bd9a56a5d

[yue]

lol, i guess nothing tops a plane hitting a house when it comes to shit falling from the sky.

[revelations]

Was listening to YYC ATC on friday and heard them mentioning this to departing aircraft.

Accoring to Norad it was supposed to crash in Newfounland but ended up skipping off the atmosphere and was purposed to crash into Alberta - guess that didnt happen.

[Legless_Marine2]

Originally posted by BlueGoblin
[B]A very large (described in media reports as the size of a school bus or pickup truck) chunk of Russian Rocket booster was very briefly set to strike Calgary on Friday morning... The booster fortunately ended up breaking apart and came down in the Atlantic Ocean

WTF?

Predicted to hit Calgary, buy ended up hitting the other side of the planet?

Did someone forget to carry a "1"??

[CUG]

Originally posted by Legless_Marine2


WTF?

Predicted to hit Calgary, buy ended up hitting the other side of the planet?

Did someone forget to carry a "1"?? My thoughts exactly... who the hell was doing the math that couldn't come up with a mmmm 5000 kilometer error?

[Grogador]

uh well hitting the atmosphere at mach 20-some does tend to affect trajectories... spaceships that want to reenter have a pretty narrow target window to hit, otherwise they go too steep and get killed by like 20G's, or too shallow and skip off onto another continent, or back into space.

// thank you, Star Trek!

[BlueGoblin]

I expect that a lot was dependent upon whether the booster stayed intact or broke up as well as where it broke up in the atmosphere.

Once it disintegrated, it would have come down very quickly.

[ZenOps]

If it remained in one piece it might have hit Calgary.

If it broke up into two large pieces, it might have hit anywhere on the planet (at a very very specific latitude however)

It can also disintegrate into more than two pieces, and therefore never have the mass to break through the lower atmosphere.

These things travel at enormous speed. They are lower than Low Earth Orbit, in LEO objects must maintain a speed of 8 Kilometers/second to stay up (27,400 KM/H)

The potential for damage from a bus size piece travelling at that speed could easily rival an artillery shell, or about 2 blocks of downtown levelled.


I believe this one would have circled the earth every 17 minutes.

Honestly though - The idea of a smaller nation figuring out that they could technically launch higher density and hardness than lead "no disintegrate buckshot" satellite weapon into below LEO orbit - and then fire a few kilograms at a city at 8KM/Sec + scares the crap out of me.

A pea sized piece could rip right through several steel reinforced buildings. Shotgun in space is a devastating weapon, probably much cheaper and greater scope than an ICBM too.

[BlueGoblin]

Athough they do travel very quickly in low earth orbit, they lose velocity substantially in the atmosphere; that's were all the heat comes from on re-entry.

If the debris had remained intact, impact with the earth would have been made at a much slower speed - very probably subsonic.

If you look at the remnants of other large objects that have de-orbited and struck the earth - Skylab and Columbia for example - you'll see that some debris stays intact even after impact. A tank from Skylab was surprisingly intact after hitting Australia, and after the Columbia disaster there were even small worms from an experiment that survived the disintegration and impact within aluminum containers. That wouldn't have happened with a truly high speed impact.

If this did end up hitting the city, it would make a mess like a small but fast moving plane might; perhaps like a military training plane moving at cruising speed..... Still quite a mess though.

[theken]

When is more shit supposed to hit?

[BlueGoblin]

Well, we only had a half hour's notice for the last one, so anybody's guess is as good as the next guy's.

The bit that had the chance of hitting Calgary was one specific piece; a booster from a Russian rocket launched a few days ago. We shouldn't be at any more risk from that launch.

[old&slow]

pics of space junk!
http://blog.wired.com/wiredscience/2009/02/spacestuff.html

[ZenOps]

Its is lucky that the satellites are usually made of the absolute lightest materials possible.

Lighter than aircraft grade aluminium, and materials like the foam on the space station, which is typically less dense than styrofoam. About the heaviest thing on these things are the solar panels, which do tend to catch a lot of atmosphere - and yes, all those factors will probably make the crash sub-sonic.

However - if there is any uranium on it, and somehow manages to detach from the main debris - the density of it will not slow down much in the atmosphere. It will probably hit with at least 3x the force of shooting it out of a gun - and thats without any extra acceleration (just dropping it from the satellite)