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View Full Version : How many man made satellites are in orbit?


Nobody
08-11-2005, 08:33 PM
Of course the number of spy satellites each country has is probably unknown, but using the best known information, and adding that number to all of the other types of satellites, I.E., relaying satellite and broadcast TV stations, weather forecasting, GPS, cell phone relaying, and all the other kinds of satellites out there, both in synchronous and geosynchronous orbit, is it know how many there are?

Q.E.D.
08-11-2005, 08:55 PM
Depending on your definition of "satellite" there are from about 3,000 to about 5,000 or so functional satellites and well over 6,000 bits of space debris which loosely fit the definition of "artificial satellite", and are trackable by radar according to this page (http://hypertextbook.com/facts/2004/VadimBlikshteyn.shtml). There is, of course, at least one natural satellite.

chrisk
08-11-2005, 09:02 PM
Yes, the definitions are pretty ambiguous, especially considering the first 'artificial satellites' wouldn't really count as functional satellites by today's standards... did sputnik 1 even have a radio broadcast antenna? (I would think so, just to make sure they could find it. ;) )

Padeye
08-11-2005, 09:13 PM
Sputnik 1 did, that's how thousands of amateur radio operators were able to track it

some time ago someone posted a link to a NASA applet that displays orbits of whatever satellites you choose but I can't find the link on my PC.

Q.E.D.
08-11-2005, 09:23 PM
some time ago someone posted a link to a NASA applet that displays orbits of whatever satellites you choose but I can't find the link on my PC.
Probably this one (http://science.nasa.gov/Realtime/JTrack/3D/JTrack3D.html), called JTrack. It's a Java applet, so you'll need Java support installed for your browser, naturally.

Nobody
08-11-2005, 09:32 PM
Depending on your definition of "satellite" ...
Yes, the definitions are pretty ambiguous
:confused: Lately the board has been overrun by statements such as "depends on what you mean by X". To avoid this, I said "man made", I said "in orbit", and I gave examples of the kinds of satellites I was talking about. I spelled it out as clearly as I could. How could my question even be close to vague?

Q.E.D.
08-11-2005, 09:46 PM
...and all the other kinds of satellites out there...
The above statement is what throws your entire question into the territory of ambiguity, hence the language of the replies.

Nobody
08-11-2005, 11:07 PM
I'm sure that I wasn't listing them all, so I gave a few examples, and then said "all the other kinds of satellites out there". I didn't say "all the other kinds of man made satellites" because "man made" is implied.

Q.E.D.
08-11-2005, 11:19 PM
I realize that. But a piece of STS tile that detaches in orbit is man made too. As such, it is a satellite under some definitions of the term. If you mean those that are intentionally orbiting and are currently functional (and I think that's what you're trying to ask), well, my first post covered that, too.

Nobody
08-11-2005, 11:23 PM
I realize that. But a piece of STS tile that detaches in orbit is man made too. As such, it is a satellite under some definitions of the term. If you mean those that are intentionally orbiting and are currently functional (and I think that's what you're trying to ask), well, my first post covered that, too.
Yes, that's exactly what I was asking. Thank you for the info.

Sage Rat
08-12-2005, 02:50 AM
The OP implies that we wouldn't know the number of spy satellites.
While I can imagine not knowing whether a satellite is intended solely for spy purposes, it would be my understanding that launching the sucker would be difficult to make secret--and some space-junkie would have noted it down. Is this accurate? Or can we launch satellites off of a carrier in the middle of the Pacific where no one* can see it or such?

* Except the military personel of course.

kanicbird
08-12-2005, 06:39 AM
How many are around Mars?

Nobody
08-12-2005, 06:57 AM
The OP implies that we wouldn't know the number of spy satellites.
While I can imagine not knowing whether a satellite is intended solely for spy purposes, it would be my understanding that launching the sucker would be difficult to make secret--and some space-junkie would have noted it down. Is this accurate? Or can we launch satellites off of a carrier in the middle of the Pacific where no one* can see it or such?

* Except the military personel of course.
Of course the number of spy satellites each country is probably unknown
Bolding mine.

Diceman
08-12-2005, 07:49 AM
The number of spy satellites isn't public knowledge, but I imagine that most of the major world powers have at least a rough idea of how many spy satellites are pointed at them.

chrisk
08-12-2005, 09:10 AM
:confused: Lately the board has been overrun by statements such as "depends on what you mean by X". To avoid this, I said "man made", I said "in orbit", and I gave examples of the kinds of satellites I was talking about. I spelled it out as clearly as I could. How could my question even be close to vague?

Sorry if I was being difficult. But as QED has already pointed out, the examples of the kinds of satellites you were talking about had other criteria implied besides being man-made and in orbit... that is, they were all launched deliberately and have some sort of communicative or sensory function. That's why we were quibbling over the definitions.

Emerald Hawk
08-12-2005, 10:14 AM
The OP implies that we wouldn't know the number of spy satellites.
While I can imagine not knowing whether a satellite is intended solely for spy purposes, it would be my understanding that launching the sucker would be difficult to make secret--and some space-junkie would have noted it down. Is this accurate? Or can we launch satellites off of a carrier in the middle of the Pacific where no one* can see it or such?

* Except the military personel of course.Satellites are nearly impossible to launch secretly with our current technology. Chemical rockets are just too easy to see, especially from space with an IR sensor. One idea would be some sort of stealth space plane, but even then you would probably need a fairly powerful rocket for the final push to orbit (like SpaceShipOne (http://www.scaled.com/projects/tierone/) had). Or you could launch two satellites in one rocket, with the secret one separating from the public one once they are in space. Give the secret one a small radar cross section, coat it with radar absorbing paint, and have it alter its trajectory every day or so. This might work, but the cost would be very high.

For some info on possible attempts to launch stealth satellites, check out this space.com article (http://www.space.com/businesstechnology/technology/mystery_monday_050103.html). These projects were probably not successful, as the satellites seem to be easily tracked by amateurs. However, it's possible that the decoy idea I described above was used, and there really is one that cannot be tracked. Either way, the projects were very expensive.

Most of the time, spy satellites are just given a cover story of being a weather or communications satellite, like Corona was.

scr4
08-12-2005, 12:03 PM
...especially considering the first 'artificial satellites' wouldn't really count as functional satellites by today's standards... did sputnik 1 even have a radio broadcast antenna? (I would think so, just to make sure they could find it. ;) )
Perhaps you're thinking of the Echo (http://en.wikipedia.org/wiki/Echo_satellite) satellites which didn't have antennas. They were just big balloons for reflecting radio waves.