Quote from: Targeteer on 09/02/2013 04:40 amQuote from: Targeteer on 08/31/2013 10:54 pmQuote from: Targeteer on 08/29/2013 05:03 pmNumerous amateur observations indicate the payload is in the now standard, expected operational 252 km X 996 km orbit inclined 97.8829 degreeshttp://www.satobs.org/seesat/Aug-2013/0210.htmlObservers have detected the first maneuver to a 254 X 1002 km orbithttp://www.satobs.org/seesat/Aug-2013/0244.htmlManeuver #2 detected and the orbit is now 265 X 1002 kmhttp://www.satobs.org/seesat/Sep-2013/0013.htmlCorrection to the orbit after maneuver #2--259 X 1007 kmhttp://www.satobs.org/seesat/Sep-2013/0052.html
Quote from: Targeteer on 08/31/2013 10:54 pmQuote from: Targeteer on 08/29/2013 05:03 pmNumerous amateur observations indicate the payload is in the now standard, expected operational 252 km X 996 km orbit inclined 97.8829 degreeshttp://www.satobs.org/seesat/Aug-2013/0210.htmlObservers have detected the first maneuver to a 254 X 1002 km orbithttp://www.satobs.org/seesat/Aug-2013/0244.htmlManeuver #2 detected and the orbit is now 265 X 1002 kmhttp://www.satobs.org/seesat/Sep-2013/0013.html
Quote from: Targeteer on 08/29/2013 05:03 pmNumerous amateur observations indicate the payload is in the now standard, expected operational 252 km X 996 km orbit inclined 97.8829 degreeshttp://www.satobs.org/seesat/Aug-2013/0210.htmlObservers have detected the first maneuver to a 254 X 1002 km orbithttp://www.satobs.org/seesat/Aug-2013/0244.html
Numerous amateur observations indicate the payload is in the now standard, expected operational 252 km X 996 km orbit inclined 97.8829 degreeshttp://www.satobs.org/seesat/Aug-2013/0210.html
Why put USA 161 in such a low orbit as being the oldest one in the fleet would it not have less propellant onboard yet be in a orbit that needed more station keeping to preserve it being deeper into the Earth's atmosphere?
Also, USA-161 isn't the oldest member of the fleet, USA-129 is. An interesting discussion would involve why it wasn't moved into the lower circular orbit first...
Quote from: Targeteer on 12/19/2013 07:20 pmAlso, USA-161 isn't the oldest member of the fleet, USA-129 is. An interesting discussion would involve why it wasn't moved into the lower circular orbit first...Having been in orbit longer, 129 will probably have less propellant left than 161 - maybe it has an insufficient amount to be operable in the lower orbit for any meaningful amount of time. It is also worth noting that 161 and 186 could well have been launched with more propellant than 129. USA-129 was the last KH-11 to launch on the Titan IVA, perhaps the extra capacity the Titan IVB offered was used to accommodate more fuel on later spacecraft - maybe even with an extended mission such as this in mind.
Quote from: William Graham on 12/23/2013 11:35 pmQuote from: Targeteer on 12/19/2013 07:20 pmAlso, USA-161 isn't the oldest member of the fleet, USA-129 is. An interesting discussion would involve why it wasn't moved into the lower circular orbit first...Having been in orbit longer, 129 will probably have less propellant left than 161 - maybe it has an insufficient amount to be operable in the lower orbit for any meaningful amount of time. It is also worth noting that 161 and 186 could well have been launched with more propellant than 129. USA-129 was the last KH-11 to launch on the Titan IVA, perhaps the extra capacity the Titan IVB offered was used to accommodate more fuel on later spacecraft - maybe even with an extended mission such as this in mind.Be interesting to see when 129 gets de-orbited, I expect fairly soon after 161 is in place so sometime in March or April.
Quote from: Star One on 12/26/2013 10:27 pmQuote from: William Graham on 12/23/2013 11:35 pmQuote from: Targeteer on 12/19/2013 07:20 pmAlso, USA-161 isn't the oldest member of the fleet, USA-129 is. An interesting discussion would involve why it wasn't moved into the lower circular orbit first...Having been in orbit longer, 129 will probably have less propellant left than 161 - maybe it has an insufficient amount to be operable in the lower orbit for any meaningful amount of time. It is also worth noting that 161 and 186 could well have been launched with more propellant than 129. USA-129 was the last KH-11 to launch on the Titan IVA, perhaps the extra capacity the Titan IVB offered was used to accommodate more fuel on later spacecraft - maybe even with an extended mission such as this in mind.Be interesting to see when 129 gets de-orbited, I expect fairly soon after 161 is in place so sometime in March or April.It's still living after an odd maneuver...http://sattrackcam.blogspot.nl/2014/02/usa-129-does-mark-twain.htmlhttp://sattrackcam.blogspot.nl/2014/02/usa-129-de-orbitted-and-usa-186-about.html
In several previous posts from September 2013 onwards, I analysed and prognosed changes to the KH-11 Keyhole/KENNAN/CRYSTAL optical reconnaissance satellite system. Main focus was on the changes, notably in the orbit of USA 186 (2005-042A), following the addition of USA 245 (2013-043A) as a replacement for USA 186 in the Keyhole primary West plane.Indeed, as predicted, USA 186 was moved out of the primary West plane, and started to drift towards the secondary West plane in mid-November 2013 following a manoeuvre that changed its inclination and made it loose sun-synchronisity.USA 186 is still drifting westwards. It currently is moving westward at a rate of 0.11 degree/day relative to USA 245 (2013-043A), the primary satellite in the West plane since the autumn of 2013. The difference in RAAN between the two satellites currently is slightly over 16 degrees:Late 2013 and early 2014, I expected that the drift would end early February 2014, when the RAAN difference between USA 245 and USA 186 reached 10 degrees, the old separation between USA 186 and USA 129, the former primary and secondary West plane satellites. I was proven wrong with my prediction, when USA 186 continued to drift past that date.I then turned to a second scenario: that the intended RAAN difference between USA 245 and USA 186 will be 20 degrees, similar to the difference between USA 224 and USA 161 in the East plane.With the current rate of precession of 0.1111 degrees/day relative to USA 245, the RAAN difference between USA 186 and USA 245 will reach 20 degrees near May 1. So I expect USA 186 to manoeuvre into a lower, sun-synchronous orbit on or near that date. The KH-11 constellation will then look like this:An open question is what will happen to USA 129 (1996-072A), the over 17 year old former secondary West plane satellite. I still think it will be de-orbited somewhere this year. But I have been wrong before.Note: the orbits for USA 129, USA 186 and USA 245 in the West plane in the images above are based on recent observations. The East plane satellites USA 161 and USA 224 have not been observed since autumn 2013, and will not be visible from the Northern hemisphere before mid-April. There is therefore a possibility that one or both have moved, but since we have no information on their current whereabouts, I have depicted them in their 'old' orbital planes of the autumn of 2013 relative to the West plane.
What is the expected lifetime in such an orbit?