Space Collisions

[Stiganator]

..

 

[CycloWizard]

Someone said in the GPS thread that the vast majority of satellites are geostationary, so it's not as big of a problem as it would be otherwise. Still, I wonder how many satellites are in orbit. This guy speculates that there are a few hundred active satellites in orbit as of 2005, but that seems really low to me - I would have guessed thousands. I suppose that's why they interviewed him and not me. The odds of moving satellites hitting each other would have to be very small indeed since there are so few of them, though i suppose the risk is increased because one would presume that certain parts of the sky are more popular than others.

 

[Aberforth]

There are about 2500 satellites in operation, you can track upto 900 here: http://science.nasa.gov/realtime/

Edit: If you have a fairly powerful telescope, you can track International Space Station and satellites closer to the earth. You can get the sighting info from here: http://spaceflight1.nasa.gov/realdata/sightings/ - just make sure you have a good telescope, coma-free telescopes can give you very good quality image.

 

[Gibsons]

Active satellites are only a fraction of the problem though, there's a lot debris/junk floating around. At orbital velocities, very small objects can do a lot of damage.

Here's a UN report on the problem from '99. PDF

 

[BladeVenom]

At the speeds they are moving something as small as a paint chip can be a hazard.

 

[SonicIce]

Originally posted by: Aberforth
There are about 2500 satellites in operation, you can track upto 900 here: http://science.nasa.gov/realtime/

Edit: If you have a fairly powerful telescope, you can track International Space Station and satellites closer to the earth. You can get the sighting info from here: http://spaceflight1.nasa.gov/realdata/sightings/ - just make sure you have a good telescope, coma-free telescopes can give you very good quality image.

You can not use a telescope, the ISS moves way too fast. I saw it 3 times. By the time you're done fiddling with the telescope it will already be gone. It looks like it moves about the speed of a plane in the sky. Try to keep a plane in your telescope view for more than a split second.

You can use binoculars, though. I tried 10x50 binoculars and it just turned the white dot into a slightly bigger white dot

The good news is you don't even need anything but your eyes. The ISS is super bright when the MAX ELEV is about like 50 deg or above. In fact I heard its the 3rd brightest object in the sky (Sun and moon are much brighter of course and not counting planes)

 

[Aberforth]

Originally posted by: SonicIce

Originally posted by: Aberforth
There are about 2500 satellites in operation, you can track upto 900 here: http://science.nasa.gov/realtime/

Edit: If you have a fairly powerful telescope, you can track International Space Station and satellites closer to the earth. You can get the sighting info from here: http://spaceflight1.nasa.gov/realdata/sightings/ - just make sure you have a good telescope, coma-free telescopes can give you very good quality image.

You can not use a telescope, the ISS moves way too fast.

nah, I've done it plenty of times, you just have to program your telescope to track the object.

http://www.telescopes.com/tele...retienuhtccoatings.cfm

 

[SonicIce]

Originally posted by: Aberforth

Originally posted by: SonicIce

Originally posted by: Aberforth
There are about 2500 satellites in operation, you can track upto 900 here: http://science.nasa.gov/realtime/

Edit: If you have a fairly powerful telescope, you can track International Space Station and satellites closer to the earth. You can get the sighting info from here: http://spaceflight1.nasa.gov/realdata/sightings/ - just make sure you have a good telescope, coma-free telescopes can give you very good quality image.

You can not use a telescope, the ISS moves way too fast.

nah, I've done it plenty of times, you just have to program your telescope to track the object.

http://www.telescopes.com/tele...retienuhtccoatings.cfm

:Q I stand corrected. But my telescope is a $15 drugstore special

Anyways. I saw something on TV about all of the available orbital "parking spaces" so I assume someone is keeping track of everything thats up there. Also note that the ISS is about 190 miles up but a geostationary satellite is about 20,000 miles up so I assume there is plenty of space left for those.

 

[funkymatt]

It's not the new satellites we have to be afraid of, it's the ones that are already up there. It takes a LOT of money to launch a satellite, so smaller foreign countries usually piggy back on other missions. Once a satellite is decomissioned, the US sends a kill signal which allows it to exit orbit. The Russians don't do this and their crap stays in orbit, because they're unmonitored it can be knocked off course- which is most likely what caused the most recent collision.

 

[Aberforth]

Years ago, there were people who wanted to launch their own private satellites into the orbit, somehow they got hold of hydrazine, liquid hydrogen and other rocket fuels and they wanted to do it, obviously they didn't succeed. Today, universities and other research institutes has to rely on NASA or ISRO (from India) to launch their modules, There is so much junk up there that it seems wise to setup a space debris and satellite trajectory monitoring center.

Space Pollution: http://en.wikipedia.org/wiki/Fileebris-GEO1280.jpg

 

[JTsyo]

I saw NASA was looking into if it was safe to launch teh shuttle since the collision.
an article

 

[Cogman]

It seems like most people forget just how big the earth is. Yes, there is a lot of stuff up there, but really, the likelihood of it colliding is lower then that of you throwing a rock up in the air at random and hitting a bird. Yeah, it could happen, but its not that likely.

Just think, 510,072,000 km of surface area! (and that is on the earths surface! Satellites don't fly at the same altitude, they fly very high in the atmosphere as well). We have 2500 satellites in the air that generally occupy maybe 3 m^3. Yeah, that's not that much. Yes, they are moving, but its still pretty unlikely that they will hit each other.

 

[JTsyo]

Originally posted by: Cogman
It seems like most people forget just how big the earth is. Yes, there is a lot of stuff up there, but really, the likelihood of it colliding is lower then that of you throwing a rock up in the air at random and hitting a bird. Yeah, it could happen, but its not that likely.

Just think, 510,072,000 km of surface area! (and that is on the earths surface! Satellites don't fly at the same altitude, they fly very high in the atmosphere as well). We have 2500 satellites in the air that generally occupy maybe 3 m^3. Yeah, that's not that much. Yes, they are moving, but its still pretty unlikely that they will hit each other.

But you stay up there long enough and your chances mount. Also the more crap you put up there the higher the chance too.

 

[Modelworks]

Originally posted by: Cogman
It seems like most people forget just how big the earth is. Yes, there is a lot of stuff up there, but really, the likelihood of it colliding is lower then that of you throwing a rock up in the air at random and hitting a bird. Yeah, it could happen, but its not that likely.

Just think, 510,072,000 km of surface area! (and that is on the earths surface! Satellites don't fly at the same altitude, they fly very high in the atmosphere as well). We have 2500 satellites in the air that generally occupy maybe 3 m^3. Yeah, that's not that much. Yes, they are moving, but its still pretty unlikely that they will hit each other.

Except that some satellites need to be in orbit at specific spots. If that orbital location becomes filled with junk, you have a serious problem.

Television satellites are like that. Can you imagine the trouble of someone like Driectv having to relocate to a new location.

 

[dkozloski]

At present there are hundreds of millions of pieces of space junk of varying sizes. There have been at least three major collisions involving active satellites and junk. The ISS has been hit with small particles of space junk numerous times. Luckily none have involved disabling damage. DOD has tracked and cataloged space junk for years but a lot of this stuff is tiny. It's going to be a constantly increasing problem.

 

[KIAman]

This is obviously a growing problem with more severe consequences in the future because of a lack of coordination among nations to solve the problem.

Oh, I didn't mean global warming, although, it wouldn't be bad to have an Al Gore-like figure to make a powerpoint about space junk.