Tracking Satellites That Aren't There

stacybro writes "Wired is running an interesting article about amateur astronomers tracking "black" satellites." From the article: "The observers, who congregate on a Web site called Heavens-Above and a mailing list called SeeSat-L, have amassed an impressive collection of information and expertise. For two decades, they have played a high tech game of hide-and-seek with the US's National Reconnaissance Office, a secretive satellite agency. By coordinating their efforts, amateur observers in Europe, North America, and South Africa monitor satellites at different phases of their journeys and extrapolate the precise dimensions of their orbits." This is in addition to the ones we know about and even the ones we think we know about.

Heavens-Above

[CheshireCatCO]

For the record, Heavens-Above.com isn't just devoted to tracking spy sats, although I would have gotten that impression from the blurb. The site tracks all kinds of satellites -- including ISS, the shuttle (if it were up), and the Iridium constellation. It's not just for people with a specific interest in spy sats and it is in fact very handy if you want to see what you might be able to see on a given night before going out to observe. (Showing friends or students the shuttles, the space station, or Iridium flares is pretty neat, so I always take a look before observing.)

Re:Security Through Obscurity Fails Yet Again

[Forbman]

Although in my gut I don't particularly like the fact that our military satellite orbits are known to all who care to look on the Internet, the article gets the moral of the story right.


Well...most satellites have limited propellant onboard to do anything more except adjust their orbit to maintain its intended design, whether it is a geostationary orbit or a "normal" orbiting orbit. They do not carry sufficient propellant to move from a polar orbit to a less inclined orbit, a high apogee orbit to low apogee orbit, etc. Orbital mechanics are pretty straight forward, and it only takes a few observations of some object to figure out its orbit. If they do, they have a very finite amount, and any large scale manouvering is not undertaken lightly, as it directly affects the lifetime of the satellite.

the obscurity required in this case isn't information about the orbit, nor should anyone really care, but on the use and purpose of the satellite. Is that "black" satellite a RORSAT? LIDAR? SIGINT? Keyhole? VESTA? THAT part about the satellite and its mission is the real secret. Orbital information has been published in astronomy magazines for some time anyways.

If you've read any tom clancy novels, you would understand that most of the baddies already know when the intelligence satellites are going to be overhead, and adjust their activities accordingly if they don't want to be directly observed.

If they are observed, either they don't know (hardly likely these days) or they DO want us to know.

Even the civilian LANDSAT and other geo-observational satellites could be determined to be "spy" satellites. Want to see how Iran's economy is doing? Use LANDSAT to monitor over time their agricultural lands. If the measured land isn't "right", then their crops have failed, which means more instabilit.

Propellant not the only way of moving a satellite

[johnthorensen]

Ever heard of a reaction wheel? Basically, it's a spinning gyroscope, with a servo on the end of the axis. By turning against the force axis, a satellite (or the space station, or any other body) can reorient itself. With enough surplus solar power budget for this sort of thing, a satellite could rotate at will without burning a limited resource like propellant.

-JT

Re:Propellant not the only way of moving a satelli

[Elrond, Duke of URL]

Yes, I've heard of them... even saw them being manufactured once at a Honeywell plant. But the poster did not say that propellant was the *only* way to move a satellite. The discussion was about hiding satellites and changing their orbits to avoid detection. That's not something you're going to do without propellant (and a lot of it).

Reaction wheels are great, but they only have a few real uses. One is to orient the satellite for communicating with Earth, or aiming a telescope at a star, etc. Another is to orient the satellite before igniting the engine, but, as the poster mentioned, most sats contain little additional fuel after they have been placed in their intended orbits.

Re:Propellant not the only way of moving a satelli

[Mishra2002]

You can't change an orbit with a reaction wheel. Reaction wheels are for pointing and positioning. the delta V required for even a degree of plane change is enormous.