Russians Track Troubled US Spy Satellite

[ozone]

http://www.space.com/news/081202-miitary-satellite-drift.html

 

[SiberianTiger]

http://www.space.com/news/081202-miitary-satellite-drift.html

That's not "Russians":

As of the beginning of 2008 the ISON network consists of 18 scientific institutions in various nations, 18 observatories and observation facilities, 25 optical instruments, and more than 50 observers and researchers.

 

[simonpro]

ISON is a Russian organised and Russian led scientific project, however. They are the PI and so in that respect it is Russian.

 

[ar81]

Sounds like countries are playing videogames these days.

 

[garyw]

Sounds like the media are trying to promote a scare where none exists.

 

[simonpro]

Sounds like countries are playing videogames these days.

What is it with you and videogames? I noticed those comments in the Mumbai Bombings thread too.
The world is not a damned videogame!

Sounds like the media are trying to promote a scare where none exists.

Indeed. DSP-23 is a bit of a problem, though: One of the satellites we use was shut down yesterday as the operators have had to prepare it for maneuvering, DSP-23 is scheduled to pass fairly close to it on Friday.
That said, the thing is still communicating with the ground so perhaps it's a thruster issue. If it is they might be able to work around it eventually.

 

[SiberianTiger]

Indeed. DSP-23 is a bit of a problem, though: One of the satellites we use was shut down yesterday as the operators have had to prepare it for maneuvering, DSP-23 is scheduled to pass fairly close to it on Friday.

Isn't the KazSat of a similar issue to you?

 

[ar81]

What is it with you and videogames? I noticed those comments in the Mumbai Bombings thread too.
The world is not a damned videogame!

War of Iraq was seen as a videogame. Precision bombs made it look like that. Pure, sterilized of blood and suffering.

When 9/11 happened, that media show culture made it to be was seen in this country like a Hollywood fireworks show, for it happened on TV. It was like seeing Armageddon movie. Just a show. Kids at school wanted flight sims to crash a craft against WTC. Unfortunately for them Orbiter did not have WTC.

US media makes a show out of everything.

 

[simonpro]

Isn't the KazSat of a similar issue to you?

As far as I know Kazsat is under full control again. Not sure if it's functional, but it's currently still in it's orbital slot at 105 East.

 

[SiberianTiger]

As far as I know Kazsat is under full control again. Not sure if it's functional, but it's currently still in it's orbital slot at 105 East.

Actually, it suffered a sudden death and a complete loss of attitude on Dec. 1, no reports on drift, though. But, surely, 105 East is not so close to what you might be controlling. The closest would be the Eutelsat 2 F-1 at 97.8 E, right?

 

[simonpro]

Interesting. I didn't know it'd been lost again...it's only been about 2 weeks since they regained control!

You're dead right though, I've just checked and it's orbital slot is 103, not 105..so it's already drifting. Eutelsat is not at risk, though, as the things only ever drift Eastwards. The two asiasats at 105 and the bunch of satellites at 109 are probably a little nervous though!

 

[SiberianTiger]

The two asiasats at 105 and the bunch of satellites at 109 are probably a little nervous though!

At times like these, Roger Wilco and his space garbage scow are to be missed!

 

[garyw]

Fascinating stuff simpro - I'm going to have to go and have a look at the oribital details of these birds now

 

[tblaxland]

You're dead right though, I've just checked and it's orbital slot is 103, not 105..so it's already drifting. Eutelsat is not at risk, though, as the things only ever drift Eastwards. The two asiasats at 105 and the bunch of satellites at 109 are probably a little nervous though!

If it is drifting east it is getting lower, no? So not too much of a concern?

 

[SiberianTiger]

If it is drifting east it is getting lower, no? So not too much of a concern?

No, it's not gonna get any much lower until the trump of doom blows: it's in GEO.

 

[tblaxland]

No, it's not gonna get any much lower until the trump of doom blows: it's in GEO.

So why is it drifting east then? Surely for it to drift east it must be lower than those that are staying put? Or is one of the higher order non-spherical gravity effects coming into play?

 

[SiberianTiger]

So why is it drifting east then? Surely for it to drift east it must be lower than those that are staying put? Or is one of the higher order non-spherical gravity effects coming into play?

Hardly non-spherical, as it is in the equatorial plane. Not sure of the cause, maybe its last breath was retro-grade.

 

[simonpro]

So why is it drifting east then? Surely for it to drift east it must be lower than those that are staying put? Or is one of the higher order non-spherical gravity effects coming into play?

Yep, it's higher order non-spherical effects. Satellites will just about always drift East or West of their position (dependant upon their longitude). There are two stable points in which a satellite will sit, but anywhere else and they'll be moving around all over the joint. They also tend to have a fair amount of North/South drift going on too, as can be seen from USA197's current orbital track.

 

[tblaxland]

Hardly non-spherical, as it is in the equatorial plane. Not sure of the cause, maybe its last breath was retro-grade.

The Earth is non-spherical around the equatorial plane too due, IIRC, to inhomogeneous mass distribution. I just wasn't sure how significant those factors were. Certainly Orbiter ignores them.

Yep, it's higher order non-spherical effects. Satellites will just about always drift East or West of their position (dependant upon their longitude). There are two stable points in which a satellite will sit, but anywhere else and they'll be moving around all over the joint. They also tend to have a fair amount of North/South drift going on too, as can be seen from USA197's current orbital track.

Thanks, I guess I was just a bit confused by your comment "the things only ever drift Eastwards". Presumably the amount of north/south drift also varies with longitude. Where, as a matter of curiosity, are the two stable points?

 

[simonpro]

I was hoping you wouldn't ask that...can't remember off the top of my head. I think they're somewhere over the atlantic and somewhere over the indian ocean though.

My comment about only drifting Eastwards was applied fore USA197, for other satellites they can indeed drift both east and west.


-----Post Added-----


Just looked it up in a textbook, the stable points are at 75W and 105E, unstable points are at 15E and 165E.

Drift rate is given by:

d2L/dt2 = C*Sin(150 - 2L)

C = [16.9 + 2.9*sin(L-35)]*10e-4

Where L is the longitude in degrees.