Author Topic: KH-11 KENNEN  (Read 108665 times)

Offline 4353

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Re: KH-11 KENNEN
« Reply #120 on: 05/26/2014 03:51 PM »

USA-186 still showing on time so no maneuver yet and got a glance of USA-245 as it flared spectacularly just before disappearing over the horizon.  If I hadn't known better, I would have thought it was burning up on reentry.  It really was that bright  8)

What's your opinion on 186, has it lost manoeuvring control?

Manoeuvering or attitude control? (two different things).

So far I have not seen any observational evidence that the brightness behaviour of USA 186 has changed. So no indications of an attitude control problem. But as I wrote earlier, KH-11's do flare from time to time, so difficult to recognize tumbling.

As for manoeuvering control, the jury is out. Since November 2013, there is no clear sign of orbital manoeuvering in the orbit data: the change in orbital parameters (notably apogee altitude, Mean Motion and eccentricity) is entirely consistent with natural orbital decay.

For the moment, I prefer to think it is still intentionally drifting to some future intended value of RAAN relative to USA 245. But if this continues for many more months, it would be reason for thoughts.

Offline Star One

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KH-11 KENNEN
« Reply #121 on: 06/02/2014 05:28 PM »
USA 161 still lives it seems.

http://sattrackcam.blogspot.co.uk
« Last Edit: 06/02/2014 05:30 PM by Star One »

Offline Star One

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Re: KH-11 KENNEN
« Reply #122 on: 09/13/2014 03:07 PM »
It appears the re-organisation of the KH-11 constellation is now complete.

http://sattrackcam.blogspot.nl/2014/09/kh-11-usa-186-has-stabilized-its-orbit.html

Offline Targeteer

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Re: KH-11 KENNEN
« Reply #123 on: 09/19/2014 04:39 AM »
USA 186 maneuvered again

http://www.satobs.org/seesat/Sep-2014/0162.html

C. Bassa via Seesat-l schreef op 18-9-2014 23:00:
> Here is a search elset fitting Marco and Leo's observations from
> September 17th and mine from this evening.
>
> USA 186
> 1 28888U 05042A   14261.83539752  .00000000  00000-0  50000-4 0    03
> 2 28888  96.7416 299.1054 0067896 336.2379  73.5322 15.66440444    08
> # 20140917.81-20140918.84, 11 measurements, 0.094 deg rms
>
> Further observations will help to make sure this orbit is correct.
>
> If the orbit is correct then it suggests a manouvre at apogee around
> 18:30UT on September 17th, raising the perigee from 260 km to 320 km.


Here is my attempt as to the new orbit, based on obs by Leo, Cees and me on Sep
17 and Sep 18:

USA 186                                                     321 x 417
1 28888U 05042A   14261.82653136 0.00005447  00000-0  45817-4 0    05
2 28888  96.8506 299.2623 0071013 335.3201  24.4668 15.66435899    08

This suggest a manoeuvre on 17 Sep 17:46:15 UT in the ascending node over
Africa, only 5-6 mins after passing perigee. Result of the manoeuvre is a more
circular orbit with raised perigee and lowered apogee.

Of course, to really say something we need a better established orbit.

- Marco
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Offline Targeteer

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Re: KH-11 KENNEN
« Reply #124 on: 09/24/2014 05:02 AM »
USA 186 maneuvered yet again

http://sattrackcam.blogspot.com/

Ten days after the first post-summer-glareout observations of the KH-11 Keyhole/CRYSTAL optical reconnaissance satellite  USA 186 (2005-042A), it has made another orbital manoeuvre.

In the evening of Wednesday 17 September I was targetting the satellite in a somewhat hazy sky, using the 1.4/85mm lens and a FOV near the tip of the Big Dipper tail.

To my surprise, the satellite was over half a minute late with respect to a 3-day-old element set. This suggested a  manoeuvre. My observations were corroborated by video observations of Leo Barhorst in the Netherlands and visual observations by Pierre Neirinck in France, obtained during the same pass.

The image above shows one of my images. As it turns out, this image was taken perhaps only an hour after the manoeuvre! USA 186 is overtaking Yaogan 11 (2010-047A) in the image (the fainter shorter, upper trail). Yaogan 11 is a Chinese optical reconnaissance satellite.

Observations the following evening by Cees Bassa and me in the Netherlands showed the satellite running even more late by that time: it passed 6m 32s late, low in the west. My camera caught it very close to the image edge. A few hours later, Kevin Fetter in Canada captured it as well.

The Sept 17 and 18 observations suggest that the manoeuvre happened on Sept 17, just before I did my Sept 17 observations (perhaps only an hour before, i.e. less than one revolution!). The current orbital solutions vary a bit between analysts (the post-manoeuvre observational arc is still short), but they agree in that the manoeuvre slightly adjusted the inclination, raised perigee and lowered apogee.

The new orbit is sun-synchronous and close to a 321 x 417 km orbit (it was 265 x 440 km before the manoeuvre), i.e. perigee was raised by about 55 km and apogee lowered by about 23 km. The new orbit is more circular, and starts to conform to the orbit I envisioned in October 2013. I suspect more manoeuvres gently raising perigee and lowering apogee until an approximate 390 x 400 km orbit is reached will occur over the coming half year.

An analysis using COLA suggests the manoeuvre(s) occured on 17 September, either near 17:46 UT or 18:25 UT. Or perhaps (and I favour that) it was a double manoeuvre, performed near both of these moments.

17:46 UT corresponds to passage through the ascending node on the equator, only minutes after passing through perigee. 18:25 UT corresponds to passing through apogee.

A manoeuvre to change inclination is normally done in one of the orbital nodes, or near the poles. A manoeuvre to raise or lower perigee is normally done while the satellite passes through it's apogee, and a manoeuvre to raise or lower apogee is normally done in the perigee. If either one of these (in the current case: the perigee) closely coincides with passage through one of the nodes, this is the ideal moment to change both peri- or apogee, and the inclination in one boost, which spares fuel.

It is very difficult to  adjust the inclination, change the apogee altitude and change the perigee altitude in one manoeuvre.

My favoured scenario is therefore that a first manoeuvre happened near 17:46 UTC in or near the ascending node (and near perigee). This lowered the apogee altitude from 440 to 417 km, and allowed a slight adjustment of the inclination at the same time. Half a revolution later, while passing through apogee near 18:25 UTC, a second manoeuvre was made to raise the perigee altitude from 265 to 321 km.
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Offline Star One

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KH-11 KENNEN
« Reply #125 on: 04/18/2015 05:58 PM »
I didn't want to create a new thread to ask this question and it does touch on a topic that was discussed up thread.

I noticed on another space related forum a topic regarding recent imaging of Lacrosse satellites. Now being as are still classified what's the actual authorities view on amateurs imaging such craft. I ask because I've seen it discussed in the past about some political individuals complaining about satellite tracking sites let alone imaging them? Especially as the imaging available to amateur observers has come along so much in recent years.
« Last Edit: 04/18/2015 06:21 PM by Star One »

Offline Blackstar

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Re: KH-11 KENNEN
« Reply #126 on: 04/18/2015 06:28 PM »
I didn't want to create a new thread to ask this question and it does touch on a topic that was discussed up thread.

I noticed on another space related forum a topic regarding recent imaging of Lacrosse satellites. Now being as are still classified what's the actual authorities view on amateurs imaging such craft. I ask because I've seen it discussed in the past about some political individuals complaining about satellite tracking sites let alone imaging them? Especially as the imaging available to amateur observers has come along so much in recent years.

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Offline Targeteer

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Re: KH-11 KENNEN
« Reply #127 on: 04/18/2015 06:48 PM »
link to the referenced imaging http://aero.tamu.edu/sites/default/files/images/Alfriend/S4%203%20Aleshin.pdf

The imaging in question actually occurred in 2007
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Offline Star One

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KH-11 KENNEN
« Reply #128 on: 04/18/2015 07:02 PM »
link to the referenced imaging http://aero.tamu.edu/sites/default/files/images/Alfriend/S4%203%20Aleshin.pdf

The imaging in question actually occurred in 2007

But is it the first time it has been seen in 'public' as the comment attached was to me couched in terms that it was new data that may finally resolve 5's well known disappearing act?
« Last Edit: 04/18/2015 07:06 PM by Star One »

Offline Targeteer

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Re: KH-11 KENNEN
« Reply #129 on: 04/18/2015 07:26 PM »
That same forum--SeeSat-L-- had a link to this 2012 video that appears to show the same thing...

Best quote heard during an inspection, "I was unaware that I was the only one who was aware."

Offline Blackstar

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Re: KH-11 KENNEN
« Reply #130 on: 04/18/2015 08:11 PM »
link to the referenced imaging http://aero.tamu.edu/sites/default/files/images/Alfriend/S4%203%20Aleshin.pdf

The imaging in question actually occurred in 2007

But is it the first time it has been seen in 'public' as the comment attached was to me couched in terms that it was new data that may finally resolve 5's well known disappearing act?

No, some of this has been public for many years. I forget when I got this.

Offline Star One

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KH-11 KENNEN
« Reply #131 on: 04/18/2015 10:14 PM »
Interesting. But perhaps new for Lacrosse 5 in particular which is seemingly different to the others?

I wonder if this change accounts for the almost five year launch gap between it and 4.
« Last Edit: 04/18/2015 10:34 PM by Star One »

Offline 4353

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Re: KH-11 KENNEN
« Reply #132 on: 04/19/2015 02:57 PM »
USA 186 has actually been manoeuvered back in a sun-synchronous orbit, in an orbital plane that is about 25 degrees more west in RAAN as that of the primary west plane KH, USA 245. Orbital elements (12 Apr 2015):
http://www.satobs.org/seesat/Apr-2015/0091.html

We have not recovered USA 161 yet after the winter blackout. When last observed it's orbital plane was some 20 degrees East in RAAN of the primary East plane KH, USA 224.

Offline 4353

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Re: KH-11 KENNEN
« Reply #133 on: 04/19/2015 03:02 PM »
Oops, missed a few post inbetween I see. Post above was in reply to a few posts back.




Offline Star One

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KH-11 KENNEN
« Reply #134 on: 04/19/2015 03:17 PM »
I wouldn't be all that surprised if USA 161 hadn't been de-orbited in the intervening period.
« Last Edit: 04/19/2015 03:17 PM by Star One »

Offline arachnitect

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Re: KH-11 KENNEN
« Reply #135 on: 04/19/2015 06:38 PM »
Been thinking about KH-11 recently and wondering about the sensor it used.

Some people on the internet say it used an 800x800 CCD.

When the first KH-11 launched, CCD sensors had existed for no more than 7 years. If NRO had an 800x800 monolithic sensor that could operate reliably in space in 1976, they must have been pushing the technology flat out.*

When did the KENNEN program start? It must have taken a real act of courage to design those satellites around novel solid state imaging technology. Did anybody fly a CCD in space before Dec. 1976? It's hard to believe they could reliably make 800x800 sensors at the time they would have started making the optical system; was KENNEN originally a vidicon system?

*Galileo's SSI camera had an 800x800 CCD. They probably started working on it around 1978. It took several thousand samples to get a pair of flight qualified sensors.
« Last Edit: 04/19/2015 06:50 PM by arachnitect »

Offline Blackstar

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Re: KH-11 KENNEN
« Reply #136 on: 04/19/2015 07:10 PM »
Been thinking about KH-11 recently and wondering about the sensor it used.

Some people on the internet say it used an 800x800 CCD.

When the first KH-11 launched, CCD sensors had existed for no more than 7 years. If NRO had an 800x800 monolithic sensor that could operate reliably in space in 1976, they must have been pushing the technology flat out.*

When did the KENNEN program start? It must have taken a real act of courage to design those satellites around novel solid state imaging technology. Did anybody fly a CCD in space before Dec. 1976? It's hard to believe they could reliably make 800x800 sensors at the time they would have started making the optical system; was KENNEN originally a vidicon system?

*Galileo's SSI camera had an 800x800 CCD. They probably started working on it around 1978. It took several thousand samples to get a pair of flight qualified sensors.

Go read "The Wizards of Langley." They used a different kind of sensor for the first two satellites. But they ended up using linear arrays, not square.

Offline arachnitect

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Re: KH-11 KENNEN
« Reply #137 on: 04/19/2015 07:35 PM »
Been thinking about KH-11 recently and wondering about the sensor it used.

Some people on the internet say it used an 800x800 CCD.

When the first KH-11 launched, CCD sensors had existed for no more than 7 years. If NRO had an 800x800 monolithic sensor that could operate reliably in space in 1976, they must have been pushing the technology flat out.*

When did the KENNEN program start? It must have taken a real act of courage to design those satellites around novel solid state imaging technology. Did anybody fly a CCD in space before Dec. 1976? It's hard to believe they could reliably make 800x800 sensors at the time they would have started making the optical system; was KENNEN originally a vidicon system?

*Galileo's SSI camera had an 800x800 CCD. They probably started working on it around 1978. It took several thousand samples to get a pair of flight qualified sensors.

Go read "The Wizards of Langley." They used a different kind of sensor for the first two satellites. But they ended up using linear arrays, not square.

That makes much more sense, thanks.

Offline Star One

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Re: KH-11 KENNEN
« Reply #138 on: 04/19/2015 08:13 PM »

Been thinking about KH-11 recently and wondering about the sensor it used.

Some people on the internet say it used an 800x800 CCD.

When the first KH-11 launched, CCD sensors had existed for no more than 7 years. If NRO had an 800x800 monolithic sensor that could operate reliably in space in 1976, they must have been pushing the technology flat out.*

When did the KENNEN program start? It must have taken a real act of courage to design those satellites around novel solid state imaging technology. Did anybody fly a CCD in space before Dec. 1976? It's hard to believe they could reliably make 800x800 sensors at the time they would have started making the optical system; was KENNEN originally a vidicon system?

*Galileo's SSI camera had an 800x800 CCD. They probably started working on it around 1978. It took several thousand samples to get a pair of flight qualified sensors.

Go read "The Wizards of Langley." They used a different kind of sensor for the first two satellites. But they ended up using linear arrays, not square.

You've mentioned that book a few times now so I'll have to track a copy down.

Offline kevin-rf

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Re: KH-11 KENNEN
« Reply #139 on: 04/19/2015 08:29 PM »
I believe it has been mentioned, the first few use Silicone Diode Arrays, then as Blackstar said a switch to linear CCD arrays was made.

It would be interesting to see what they use now, a linear array lets you sweep a large area, while a square/rectangular array gives you a sit and stare capability. Both have advantages, besides, depending how similar the optics are to Hubble, you could select multiple image sensors with a flip mirror with each tailored to the type of data that needs to be collected.

In the "famous" leaked aircraft carrier image you can see sensor effects that indicate some sort of linear array was used.
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