The Fun Of Watching Secret Satellites
from Gerhard Holtkamp, 20. September 2009, 10:41
Although their existence is officially acknowledged when launched the whereabouts of many military satellites is kept secret. Naturally I enjoy watching them all the time...
You don't have to be on a high mountain in the middle of a desert to make interesting sky observations. Watching satellites is one of the activities which can be done even in light-polluted city skies (although it's still better to be out in dark country). And as every child knows watching something that others would rather prefer you not to see gives you the most pleasure.
The U.S. Space Command keeps track on objects orbiting the Earth (active and inactive satellites, rocket stages and smaller space debris) via their Space Surveillance Network and publishes the orbital elements of almost 14000 objects on the Internet. Conspiciously absent from this list are classified U.S. military satellites (but military satellites of other countries except Japan are included).
We are not really in a position to complain about this practice of keeping those classified satellites off the Internet as this service is provided and exclusively paid for by the U.S. military. The situation is somewhat similar to the GPS system which is also run by the U.S. military but made available to the public free of charge. (Although military satellites in their own right the positions of GPS satellites are officially published.)
The military usefulness of keeping the postions of those satellites classified is questionable at best. Other countries like Russia and probably China have enough space surveillance capabilities to keep track of them. Better yet many of these satellites are bright enough to be seen through ordinary binoculars or even with the naked eye.
Here is a picture I took with a simple digital compact camera out of my window from within the city. It shows the trail of Lacrosse 5 which is a large high resolution radar imaging satellite. Equipped with nothing more than a stop watch and binoculars or a small telescope with a camera attached to it a group of amateur observers scattered around the world manages to gather enough positional information of classified satellites to come up with accurate orbital elements which are then placed on the Internet.
Thanks to this information I know when to look where to observe secret satellites. Some of them are quite fun to watch. The NOSS (Navy Ocean Surveillance System) series come in pairs or triplets and are usually weak and only visible through binoculars. But on occasion they can produce bright flares. As they fly in formation an unsuspecting observer might be lead to believe that some Martians attack with flying saucers!
My personal favorite is the already mentioned Lacrosse 5. This is a bus-size satellite which is easily visible to the naked eye - most of the time. Apart from occasionally flaring up it has a habit of disappearing sometimes for a minute or so! Well it doesn't really disappear. Its brightness drops to less than can be detected by the naked eye within two or three seconds but you would still be able to see it weakly in binoculars.
Observers seperated by several hundred kilometers have seen this effect to occur at exactly the same time. The best explanation for it seems to be the special way that light gets scattered by a large mesh antenna. Older Lacrosse satellites show this effect to a much smaller degree so the conclusion is that Lacrosse 5 employs an antenna about 50% larger than its predecessors.
Secret information is often freely available on the Internet. Here is a drawing of a Lacrosse satellite. That this is quite accurate is confirmed by a series of pictures of Lacrosse 2 taken by a special Russian telescope in the Altay mountains. (This was a prototype telescope with adaptive optics and a larger much more capable one should be operational soon.)
Amateurs would not have such equipment at their disposal but they are getting better all the time at taking pictures of satellites showing ever more details. In addition to visual observers there are also radio amateurs specialized in tuning in to the radio frequencies used by active satellites. Although they cannot decode the signals the shift in frequencies can tell you a lot about the satellite's orbit and behaviour.
Once a satellite is no longer active radio amateurs won't be able to listen in. Visual observers can only see satellites when they are illuminated by the sun and the sky is dark enough which happens only part of the time. The weather also has to cooperate. So there are significant gaps in amateur satellite tracking and the quality of the respective orbit information varies correspondingly.
One could look at classified satellites as a fun game of hide and seek played between the military and amateur observers but in reality much more is at stake. There are now so many objects in orbit around the Earth that collisions between them are ever more likely (and indeed have already occurred). As long as accurate positions of those objects are known it is possible to perform evasive maneuvers by active satellites.
Presumably the U.S. military will perform such maneuvers by their classified satellites if they see that they are on collision course with some other object. But the classified list includes not just active satellites also but inactive ones, rocket stages used to boost those satellites into orbit and debris from fragmented satellites all of which cannot be controlled anymore.
The highly questionable military benefit of keeping those orbits classified stands in no relation to the danger posed to the overall satellite infrastructure on which we depend ever more in our daily lives.
Over the next few years the European Space Agency embarks on setting a civilian multi-national space surveillance system. The exact configuration of this system is in the process of being defined as is the way the information will be divulged. It might be that some standard information will be available free of charge while more detailed information (like how accurate the individual orbit elements are) would have to be paid for by commercial custumers.
Typically something called a radar fence which is a group of phased array radars scanning different parts of the sky will be used to detect objects up to an altitude of 2000 km while objects in the geostationary belt will be tracked optically by special telescopes.
In the meantime people like me will continue to look out of the window when the sky gets dark. (And if any of my neighbours should read this blog - No I'm not spying on you with my binoculars but rather on spy satellites!)
If you are interested in satellite observations you can find information on when and where to look on the Heavens-Above site.
General information about satellite observations can be found on the SeeSat site.
Here you would also find further links with regard to types of satellites etc.
You don't have to be on a high mountain in the middle of a desert to make interesting sky observations. Watching satellites is one of the activities which can be done even in light-polluted city skies (although it's still better to be out in dark country). And as every child knows watching something that others would rather prefer you not to see gives you the most pleasure.
The U.S. Space Command keeps track on objects orbiting the Earth (active and inactive satellites, rocket stages and smaller space debris) via their Space Surveillance Network and publishes the orbital elements of almost 14000 objects on the Internet. Conspiciously absent from this list are classified U.S. military satellites (but military satellites of other countries except Japan are included).
We are not really in a position to complain about this practice of keeping those classified satellites off the Internet as this service is provided and exclusively paid for by the U.S. military. The situation is somewhat similar to the GPS system which is also run by the U.S. military but made available to the public free of charge. (Although military satellites in their own right the positions of GPS satellites are officially published.)
The military usefulness of keeping the postions of those satellites classified is questionable at best. Other countries like Russia and probably China have enough space surveillance capabilities to keep track of them. Better yet many of these satellites are bright enough to be seen through ordinary binoculars or even with the naked eye.
Here is a picture I took with a simple digital compact camera out of my window from within the city. It shows the trail of Lacrosse 5 which is a large high resolution radar imaging satellite. Equipped with nothing more than a stop watch and binoculars or a small telescope with a camera attached to it a group of amateur observers scattered around the world manages to gather enough positional information of classified satellites to come up with accurate orbital elements which are then placed on the Internet.
Thanks to this information I know when to look where to observe secret satellites. Some of them are quite fun to watch. The NOSS (Navy Ocean Surveillance System) series come in pairs or triplets and are usually weak and only visible through binoculars. But on occasion they can produce bright flares. As they fly in formation an unsuspecting observer might be lead to believe that some Martians attack with flying saucers!
My personal favorite is the already mentioned Lacrosse 5. This is a bus-size satellite which is easily visible to the naked eye - most of the time. Apart from occasionally flaring up it has a habit of disappearing sometimes for a minute or so! Well it doesn't really disappear. Its brightness drops to less than can be detected by the naked eye within two or three seconds but you would still be able to see it weakly in binoculars.
Observers seperated by several hundred kilometers have seen this effect to occur at exactly the same time. The best explanation for it seems to be the special way that light gets scattered by a large mesh antenna. Older Lacrosse satellites show this effect to a much smaller degree so the conclusion is that Lacrosse 5 employs an antenna about 50% larger than its predecessors.
Secret information is often freely available on the Internet. Here is a drawing of a Lacrosse satellite. That this is quite accurate is confirmed by a series of pictures of Lacrosse 2 taken by a special Russian telescope in the Altay mountains. (This was a prototype telescope with adaptive optics and a larger much more capable one should be operational soon.) Amateurs would not have such equipment at their disposal but they are getting better all the time at taking pictures of satellites showing ever more details. In addition to visual observers there are also radio amateurs specialized in tuning in to the radio frequencies used by active satellites. Although they cannot decode the signals the shift in frequencies can tell you a lot about the satellite's orbit and behaviour.Once a satellite is no longer active radio amateurs won't be able to listen in. Visual observers can only see satellites when they are illuminated by the sun and the sky is dark enough which happens only part of the time. The weather also has to cooperate. So there are significant gaps in amateur satellite tracking and the quality of the respective orbit information varies correspondingly.
One could look at classified satellites as a fun game of hide and seek played between the military and amateur observers but in reality much more is at stake. There are now so many objects in orbit around the Earth that collisions between them are ever more likely (and indeed have already occurred). As long as accurate positions of those objects are known it is possible to perform evasive maneuvers by active satellites.
Presumably the U.S. military will perform such maneuvers by their classified satellites if they see that they are on collision course with some other object. But the classified list includes not just active satellites also but inactive ones, rocket stages used to boost those satellites into orbit and debris from fragmented satellites all of which cannot be controlled anymore.
The highly questionable military benefit of keeping those orbits classified stands in no relation to the danger posed to the overall satellite infrastructure on which we depend ever more in our daily lives.
Over the next few years the European Space Agency embarks on setting a civilian multi-national space surveillance system. The exact configuration of this system is in the process of being defined as is the way the information will be divulged. It might be that some standard information will be available free of charge while more detailed information (like how accurate the individual orbit elements are) would have to be paid for by commercial custumers.
Typically something called a radar fence which is a group of phased array radars scanning different parts of the sky will be used to detect objects up to an altitude of 2000 km while objects in the geostationary belt will be tracked optically by special telescopes.
In the meantime people like me will continue to look out of the window when the sky gets dark. (And if any of my neighbours should read this blog - No I'm not spying on you with my binoculars but rather on spy satellites!)
If you are interested in satellite observations you can find information on when and where to look on the Heavens-Above site.
General information about satellite observations can be found on the SeeSat site.
Here you would also find further links with regard to types of satellites etc.
Of course, the observability of military satellite is irksome to the by default always secretive military authorities. It won't bother them that you can observe them, but if you can so can everyone else.
The fact that China demonstrated its capability to destroy orbiting satellites and America sent an equally clear signal back should be seen in this context.
http://en.wikipedia.org/...-satellite_missile_test
http://en.wikipedia.org/wiki/USA_193
There are persistent rumors - to some extent speculative, but some also stemming from usually well-informed sources - concerning stealth technology on future military satellites for espio .... ooops! I meant reconnaissance! purposes.
Those would, I assume, consist in a shape and surface coating that much reduces reflectivity and thus, brightness, and scatters radar signals sideways rather than back to Earth.
I further assume that these technologies will only be of limited usefulness as other interested parties in uniform will quickly find ways and means to circumvent the application of stealth technologies, thus rendering them ineffective.
That is, if such technologies work at all, it is not clear to me how to conceal a radar satellite, One could of course leave away the radar antenna and also not switch on any radar equipment when traversimg hostile territory, but that somewhat defies the whole perpose of having such a satellite, doesn't it?
Do you have any information on this?
From what I know some experiments concerning stealth technology for satellites have been done but due to the questionable success these projects have been put on hold.
As Michael pointed out it is difficult to conceal yourself if you want to perform active radar observations. This reminds me of an editorial I read many years ago in Scientific American entitled "Can the Invisible Man see?". The conclusion was that in order to see your eyes need refractive properties to bend lightrays which then would give away the positions of your eyes to outside observers and thus rendering you visible again.