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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: 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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