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On the morning of June 17, the Luxembourg-based satellite operator SES lost control of a large satellite in geostationary space, nearly 36,000km above the Earth's surface. Shortly after, the satellite operator began working with another company that specializes in space situational awareness to track the drifting machine, AMC-9. A few days ago that company, ExoAnalytic Solutions, saw the AMC-9 satellite begin to fragment.
"We have seen several pieces come off of it over the past several days," ExoAnalytic's chief executive officer, Doug Hendrix, told Ars. "We are tracking at least one of the pieces. I would hesitate to say we know for sure what happened."
Sunday 11am ET Update: In response to a query from Ars, the AMC-9 satellite's operator, Luxembourg-based SES, issued the following statement on Sunday morning:
In the early hours of 1st July, the SES Satellite Control reestablished contact to AMC-9. SES and the satellite manufacturer Thales are working around the clock to evaluate the status and define the next steps.
Tracking information received on 29 June had suggested that at least two separate objects were located in the vicinity of AMC-9. Their source has still to be determined. The new piece of information was included by Thales and SES in their investigations.
Kessler syndrome?
Source: A satellite may be falling apart in geostationary orbit
SES's AMC-9 satellite drifting after anomaly
(Score: 0) by Anonymous Coward on Monday July 03 2017, @01:20AM (12 children)
Is the Kessler syndrome possible at geo-synchronus orbit? Everything would seem to have about the same velocity.
(Score: 2, Insightful) by Ethanol-fueled on Monday July 03 2017, @01:41AM
Don't trust America for the answers. I was just watching some Youtube vids about airborne sensor failures and they called a Pitot-static* probe a "pilot" probe.
* Static vs. total pressure probe, utilizing a titanium sensing element.
(Score: 2) by cafebabe on Monday July 03 2017, @01:48AM (1 child)
Yes. As I understand, geo-synchronous satellites effectively sit in a box. There are four boxes per degree. So, 1440 boxes in total. Any mechanical failure could initiate drift into another box. This includes asteroid strike. It may take weeks for geo-synchronous orbit to become a complete debris field but we have nothing to halt it or reverse it. Indeed, we have very little which can reach it.
1702845791×2
(Score: 2) by HiThere on Monday July 03 2017, @05:47PM
FWIW, when I heard it was coming apart my first thought was "meteorite strike". This could cause changes in velocity (though that should be measurable). OTOH, if it didn't fragment the satellite, then it must have been a really small meteorite, and shouldn't cause *much* change in velocity. And geocentric orbit is a huge place. In addition to which it would be quite unlikely that the delta v would be entirely in the plane of the orbit. So I wouldn't expect much danger to other orbiting satellites...at least not the ones at any distance (say 0.001 of a degree away as viewed from earth center).
OTOH, I haven't done any calculations. If someone wants to bother they may show I'm wildly wrong.
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(Score: 3, Interesting) by khallow on Monday July 03 2017, @01:59AM (8 children)
It doesn't take much velocity to break satellites at GSO. However things indeed move slower up there and there's more space than at low Earth orbit (LEO). So we would see for a given number of objects less spectacular collisions and a longer ramp up to full Kessler syndrome than at LEO. OTOH, debris sticks around a lot longer (I seem to recall several orders of magnitude longer) so debris at GSO would be a problem for much longer.
(Score: 0) by Anonymous Coward on Monday July 03 2017, @03:01AM (3 children)
I guess my fear is that we are so damned vulnerable in this spot. One load of pea-gravel in an elliptical polar orbit intersecting this ring and everything is history.
Reminds me of my own country. We have a lot of politicians and war machines, along with impressive arrays of young men in uniforms twirling their guns in unison for display.... yet we have to import technical talent to make our stuff work, while our own aerospace executives are paid bonuses for trimming the work force.
I figure with the technical talent lost to purchase those handshakes, those have got to be among the most expensive handshakes on the planet.
(Score: 2) by aristarchus on Monday July 03 2017, @04:34AM (2 children)
And which fine earth-bound country might this be, prey tell?
(Score: 2) by isostatic on Monday July 03 2017, @09:33AM (1 child)
I wasn't sure from the description, could be North Korea, could be USA.
(Score: 1) by khallow on Monday July 03 2017, @12:24PM
(Score: 2, Informative) by pTamok on Monday July 03 2017, @07:47AM (3 children)
Slow is a relative term.
The International Space Station travels, on average at about 7 kilometres a second. Its altitude in orbit varies from about 300 to 410 km. https://en.wikipedia.org/wiki/International_Space_Station [wikipedia.org]
A satellite in geostationary orbit has an average speed of about 3 km per second. Orbital altitude is about 35,786 km. http://www.livephysics.com/problems-and-answers/classical-mechanics/find-speed-satellite-geostationary-orbit/ [livephysics.com]
Geostationary satellites are not stationary: they just happen to go round the earth at the same angular velocity as the earth rotates, so from an observer on the earth's surface they remain in the same part of the sky. If they were truly stationary, they wouldn't remain there for long: they would drop, just like a stone, in the absence of anything holding them up (like a continuously firing rocket engine).
A small meteorite could do a lot of damage. And, while the relative speed difference between two geostationary satellites is small, they are not designed to cope with even low speed collisions.
Note that geostationary satellites need to keep their position actively (called station keeping) https://en.wikipedia.org/wiki/Orbital_station-keeping#Station-keeping_in_geostationary_orbit [wikipedia.org] , otherwise, their natural movements would mean that they drift about.
These natural movements, combined with the fact the orbital parameters for geostationary satellites are exacting, mean that an uncontrolled satellite in what was originally a geostationary orbit could be extraordinarily damaging. Most geostationary satellites are designed to be able to boost to a higher 'parking' or 'graveyard' orbit at the end of their useful lives. https://en.wikipedia.org/wiki/Graveyard_orbit [wikipedia.org]
(Score: 2) by Osamabobama on Monday July 03 2017, @05:45PM (2 children)
That station keeping also includes angular momentum management. What if a small rocket motor stuck in the on position, increasing the satellite's spin rate until pieces started separating? That can be hard to recover from, as rapidly rotating antennas don't receive troubleshooting commands very well, nor transmit needed data reliably.
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(Score: 1) by pTamok on Monday July 03 2017, @07:48PM (1 child)
You may be referring to this subtly - in any event, your scenario is similar to what happened to the Japanese Hitomi X-ray astronomy satellite.
https://en.wikipedia.org/wiki/Hitomi_(satellite) [wikipedia.org]
https://spaceflightnow.com/2016/04/18/spinning-japanese-astronomy-satellite-may-be-beyond-saving/ [spaceflightnow.com]
http://global.jaxa.jp/projects/sat/astro_h/files/topics_20160415.pdf [global.jaxa.jp]
(Score: 2) by Osamabobama on Monday July 03 2017, @08:32PM
I didn't remember any details, so I used generalized language. That spaceflightnow link is pretty detailed, filling in more details than I saw the first time around.
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