Author Topic: KH-11 KENNEN  (Read 108643 times)

Offline kevin-rf

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Re: KH-11 KENNEN
« Reply #60 on: 04/16/2014 05:39 PM »
To quote blackstar

Best resolution was 2.4", 7cm obtained during the KH-8's 80 mile dives of death. (Which is oddly 1/5 of a foot).
KH-11 resolution is on the order of 10cm.

Both can make out the license plate on a car, but you can not read the letters at that resolution.

As for the Danny Devito comment, many sources have indicated that the KH-11 has a shorter focal length mirror and with a shorter tube looks like a Stubby Hubble.
 
« Last Edit: 04/16/2014 05:43 PM by kevin-rf »
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Offline Hog

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Re: KH-11 KENNEN
« Reply #61 on: 04/16/2014 06:24 PM »

Thank you for the response.
Wow, KH-8's perigee was only 80 miles(129km) that getting in close for sure, less than 1/2 of what the ISS would orbit at during the Shuttle days.

1)I'm interested in reading more, where could I find Blackstar's quotes? or any furthur info?

2) In the picture below, to add some context of resolution for me personally, what resolution is displayed?  Photo courtesy of NRO.
3) Is the picture shown a small fragment of a greater swath of data collected along the satellites path, or is their literally some sort of optical device that is panned over to the targeted building?

I remember a "Popular Science" article from the 80's, and it had a lady laying out on a chaise chair by the pool and it talked about photo recon satellites.  It gave the feeling that individual person could be photographed in detail.

Thanks again!
Paul

Offline kevin-rf

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Re: KH-11 KENNEN
« Reply #62 on: 04/16/2014 06:56 PM »
You're assuming that picture came from a KH-11, and not another platform like the U-2  (Which did operate over pre-invasion Iraq). I'm no expert, but I would say somewhere between 1 and 2 feet. You can see arms and heads.

btw. There are several threads on the earlier generation KH-9 (HEXAGON), KH-8 (GAMBIT), and KH-1 thru KH-4B (CORONA) that cover those systems.

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Online gosnold

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Re: KH-11 KENNEN
« Reply #63 on: 04/16/2014 07:11 PM »
In my book, that means they have shrunk the mass of required support equipment without shrinking the optics.

They lightweighted the optics for FIA. Go back and read some of the stuff that came out when the donation of the optics was offered. I think that was discussed here. They apparently shaved a lot of mass off of them too.

I think mass everywhere... The technology has greatly changed since the KH-11 program launched. I was just pointing out I think they saved a large amount of weight without reducing the optical quality (size resolution). While some things have not changed (size of optics, reaction wheel masses) other things have moved on (Battery tech, composite structures, lighter weight and lower power electronics, mass storage if it even uses it (they do have SDS),switching the propulsion system on many satellites from hypergolics to Ion).

Personally, when you look at the mass of the KH-9/KH-8 and then remove all the film and special film hardware I always had a problem with why is the KH-11 so heavy. Yes part of it is the larger and heavier optics but there has to be more. Is part of it due to it going to a much higher orbit (needing a larger rocket) and living longer (thus needing more propellant)? Or is there additional hardware not on the previous generation that added a fair mass penalty?

To be fair, MOL which was in the same weight class was to have a heavier light weight 1.8m telescope, a gemini capsule, and a space station to boot....

I just think this is one case where improvements in technology have led to them being able to reduce the launch mass of the satellite without compromising the data returned or size of the optics. So is it evolution or a new design.

Here's to all of us still being here and your continued good health when they get around to declassify this sy
stem.
The only figure I have seen about the mass budget of a KH-11 give 7 tonnes of propellant. It's mentioned in passing in this CNES paper about low-flying EO satellites:
Potential of elliptic orbits for theatre observation
J.-P. Aguttes ∗ , N. Fernandez, J. Foliard
Acta Astronautica 55 (2004) 659668
I figure they used the results of their study to estimated the delta-v necessary to compensate drag on a Keyhole and assumed an Isp to get to propellant mass.

Offline Hog

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Re: KH-11 KENNEN
« Reply #64 on: 04/16/2014 08:00 PM »
You're assuming that picture came from a KH-11, and not another platform like the U-2  (Which did operate over pre-invasion Iraq). I'm no expert, but I would say somewhere between 1 and 2 feet. You can see arms and heads.

btw. There are several threads on the earlier generation KH-9 (HEXAGON), KH-8 (GAMBIT), and KH-1 thru KH-4B (CORONA) that cover those systems.

Thank you for some direction. I'm understanding things a bit better.

 I have no idea what actual system the picture came from, KH-11 or other.  The picture is labelled as a "Satellite" picture, although to trust that label would be ignorant.
Paul

Offline kevin-rf

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Re: KH-11 KENNEN
« Reply #65 on: 04/16/2014 10:53 PM »
The picture in question is actually quite famous, it was presented to the UN as evidence WMD in Iraq by General Collin Powell. What took it, we don't know, but was widely assumed to be a KH-11 with no proof offered.
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Offline Star One

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Re: KH-11 KENNEN
« Reply #66 on: 05/06/2014 07:58 PM »
Quote
USA 129 (96-072A), the oldest of the KH-11 Keyhole/CRYSTAL/KENNAN optical reconnaisance satellites, has gone missing. The last observers to see it were me on April 22 and Russel Eberst on April 24. The photo below shows one of my images from April 22, with USA 129 passing near Castor and Pollux:

http://sattrackcam.blogspot.co.uk/2014/05/kh-11-usa-129-is-missing-usa-186-has.html?m=1

Offline Melt Run

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Re: KH-11 KENNEN
« Reply #67 on: 05/08/2014 01:06 PM »
To quote blackstar

Best resolution was 2.4", 7cm obtained during the KH-8's 80 mile dives of death. (Which is oddly 1/5 of a foot).
KH-11 resolution is on the order of 10cm.


Theoretical max resolution (Rayleigh) with all else perfect and 0.5 micron wavelength is 15.6 cm.
Brag factor is only 2x.

Offline Blackstar

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Re: KH-11 KENNEN
« Reply #68 on: 05/09/2014 05:18 PM »
To quote blackstar

Best resolution was 2.4", 7cm obtained during the KH-8's 80 mile dives of death. (Which is oddly 1/5 of a foot).
KH-11 resolution is on the order of 10cm.


Theoretical max resolution (Rayleigh) with all else perfect and 0.5 micron wavelength is 15.6 cm.
Brag factor is only 2x.

Except that we know it was better than that, so I think you got the calculation wrong.

48 inch (1.21 m) diameter primary mirror, focal length of 175.6 in (4.46 m), at 80 nautical miles. Gives about 3 inch resolution in yellow light.

Plus, we have a declassified document that says "better than four inches."

Offline Melt Run

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Re: KH-11 KENNEN
« Reply #69 on: 05/09/2014 05:37 PM »
To quote blackstar

Best resolution was 2.4", 7cm obtained during the KH-8's 80 mile dives of death. (Which is oddly 1/5 of a foot).
KH-11 resolution is on the order of 10cm.


Theoretical max resolution (Rayleigh) with all else perfect and 0.5 micron wavelength is 15.6 cm.
Brag factor is only 2x.

Except that we know it was better than that, so I think you got the calculation wrong.

48 inch (1.21 m) diameter primary mirror, focal length of 175.6 in (4.46 m), at 80 nautical miles. Gives about 3 inch resolution in yellow light.

Plus, we have a declassified document that says "better than four inches."
Correct calculation on wrong system. My error, I ran my numbers for the Hexagon aperture.

Offline Melt Run

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Re: KH-11 KENNEN
« Reply #70 on: 05/09/2014 07:48 PM »
Correct calculation on wrong system. My error, I ran my numbers for the Hexagon aperture.

And your numbers are not out of whack for that system...
Given 80 miles = 128 km altitude, aperture = 0.5 m the imaging F# is 128000/.5= 256000
Rayleigh limit is 1.22 x lambda x F# were I gave an optimistic 0.0000005 m wavelength.
1.22 x 0.0000005 x 256000 = 0.156 meters or 15.6 cm.

Offline kevin-rf

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Re: KH-11 KENNEN
« Reply #71 on: 05/09/2014 11:54 PM »
I posted this before, but I really wonder if the brag was able to make out feature dimensions to +/- 2.4".

Since the purpose of high resolution in this case was to measure the dimensions of objects of interest it is possible to interpolate the lines (or curves) that defines the boundary's of the feature being measured. This is different than resolving two separate points.

In the digital machine vision world it is not uncommon for vision system vendors and software vendors to advertise being able to dimension and locate objects in a single image to sub-pixel accuracy. 1/10 of a pixel is not an uncommon brag. For resolution, you need at min of three pixels to resolve two points.

Since they have not released how the value for the brag was obtained, it is quite possible what they considered resolution was the dimensional error bars on measurements and not the classic being able to resolve two distinct points. That way the brag could be correct without violating any physics. In this case, error bars on the measurements is what mattered.

Another fun fact, the brag of 2.4" is 0.2 foot... That is a very, very interesting coincidence... sounds more like an error bar on a dimension, doesn't it.
« Last Edit: 05/09/2014 11:59 PM by kevin-rf »
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Offline Star One

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Re: KH-11 KENNEN
« Reply #72 on: 05/10/2014 09:28 AM »
I wonder how long it will be before we see a commercial satellite launched that can match the resolution performance of the KH-11?

Offline Melt Run

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Re: KH-11 KENNEN
« Reply #73 on: 05/10/2014 02:07 PM »
I wonder how long it will be before we see a commercial satellite launched that can match the resolution performance of the KH-11?
It is all a matter of aperture and altitude. If we were to "ASSUME" a 2.4 meter aperture and a 275 km altitude for KH11 then it has a imaging F# of 275000/2.4 = 114583.3
When the commercial sats obtain a lower value then this then the resolution will be there.
Interesting question! I have to believe that it is a matter or return on investment and not so much a technical issue. For years in the States here the Feds limited the aperture but I think those days have passed.

Offline Star One

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Re: KH-11 KENNEN
« Reply #74 on: 05/10/2014 02:20 PM »

I wonder how long it will be before we see a commercial satellite launched that can match the resolution performance of the KH-11?
It is all a matter of aperture and altitude. If we were to "ASSUME" a 2.4 meter aperture and a 275 km altitude for KH11 then it has a imaging F# of 275000/2.4 = 114583.3
When the commercial sats obtain a lower value then this then the resolution will be there.
Interesting question! I have to believe that it is a matter or return on investment and not so much a technical issue. For years in the States here the Feds limited the aperture but I think those days have passed.

I would put good money on it being DigitalGlobe of the various international companies that achieves this first.

Offline pagheca

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Re: KH-11 KENNEN
« Reply #75 on: 05/10/2014 03:20 PM »
Years ago I've been told by a colleague (astronomer) that during the early stage of the Hubble Space Telescope design, during a presentation at a meeting someone by Kodak shown a plot of main mirror diameter vs. cost. The plot was sort of exponential as expected, with a "dive" at 2.4 m. When asked about the reason of that dive, he said he couldn't answer as this was classified (I don't need to say why here...).

How much of this story is true? If it is, when/where this happened?

p.s. Yes, I know about the relations between the KH and the HST projects. I'm just curious to know if this episode actually happened or is a dramatization of the whole story.
« Last Edit: 05/10/2014 11:21 PM by pagheca »

Offline Blackstar

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Re: KH-11 KENNEN
« Reply #76 on: 05/10/2014 03:57 PM »
I wonder how long it will be before we see a commercial satellite launched that can match the resolution performance of the KH-11?

In the U.S. commercial satellite resolution is limited by law.

Offline pagheca

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Re: KH-11 KENNEN
« Reply #77 on: 05/10/2014 04:21 PM »
In the U.S. commercial satellite resolution is limited by law.

I didn't know that. Which law?

EDIT: found that. See for example this article.
« Last Edit: 05/10/2014 04:23 PM by pagheca »

Offline Melt Run

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« Last Edit: 05/10/2014 05:26 PM by Melt Run »

Offline Star One

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KH-11 KENNEN
« Reply #79 on: 05/10/2014 05:37 PM »
I wonder how long it will be before we see a commercial satellite launched that can match the resolution performance of the KH-11?

In the U.S. commercial satellite resolution is limited by law.

I know that but I thought, as discussed in the other thread I started on reform in this area, this only applied to the publication of images in public not their creation?

So they could still launch a satellite to collect higher resolution images for government agencies just not publish them to the wider public.
« Last Edit: 05/10/2014 05:40 PM by Star One »

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