KH-8 GAMBIT Reconnaissance Satellite

[Blackstar]

Here is the 8.

[gwiz]

What about Gambit 2? The early KH-8 with single capsule?  Or something else?

Edit to add: I've now had a quick scan of the NRO documents, and the answer is "something else", an option that was not pursued.

[William Graham]

What about Gambit 2? The early KH-8 with single capsule?  Or something else?

KH-7 was Gambit 1, Gambits 2, 3 and 4 were all proposed to replace it. G2 had less modifications, but offered a less significant increase in resolution, G3 featured more changes and gave higher resolution images. G4 would have given the highest resolution. Only G3 was developed, and it became KH-8.

Block I spacecraft only carried one SRV, Block II and III carried three.

[Blackstar]

I have yet to go through the documents, but I suspect that this whole "Gambit 1" and "Gambit 3" stuff is actually created more by the NRO historians than the actual documents. A quick view of the documents indicates that they generally referred to the KH-7 and KH-8, as well as the KH-8B, etc. I'm certain that all of the imagery interpretation reports (and there were TONS of those produced) used those designations. And I suspect that the people working on the vehicles all generally used the KH designations and not "Gamibt 3," etc.

I think that the Oder/Worthman histories may have adopted that terminology and then the Haines' history from 1997 repeated it, and now the NRO's public affairs people used that in all of their press releases and documents.

But it won't be until I start doing interviews that I'll get a good sense of the common usage.

[simonbp]

Here's a nice (color!) diagram of the KH-8B, showing that it use an aspherical primary and a Ross corrector, a rather obscure (outside of diehard amateur astronomers) form of multi-lens coma corrector. The Ross corrector would have been much lighter than the Maksutov-style corrector on KH-7.

http://www.nro.mil/foia/declass/GAMHEX/GAMBIT/10.PDF

[kevin-rf]

Tough to find details on that one, from the diagram it looks to be build into the secondary. Interesting that they completely changed the optics between the KH-7 and KH-8 and still called it GAMBIT. Though to be fair, CORONA covered several revs.

btw. http://www.telescope-optics.net/sub_aperture_corrector.htm has a nice explanation of what the Ross corrector is for the rest of us.

[kevin-rf]

Okay, while digesting the video they mention an improvement to the KH-8 and at the bottom of the diagram are a set of what look like the corrector's. The top one looks like I would guess from what little I know, like a three element Ross corrector. Would the bottom diagram with the spaced lenses be maybe a Wynne corrector?

Simon?

[gwiz]

I note that the Gambit 3 only had solar arrays from the 48th mission onwards, which means that flights up to 56 days were achieved purely with battery power.

[hoku]

I have yet to go through the documents, but I suspect that this whole "Gambit 1" and "Gambit 3" stuff is actually created more by the NRO historians than the actual documents. A quick view of the documents indicates that they generally referred to the KH-7 and KH-8, as well as the KH-8B, etc. I'm certain that all of the imagery interpretation reports (and there were TONS of those produced) used those designations. And I suspect that the people working on the vehicles all generally used the KH designations and not "Gambit 3," etc.
...

A number of the documents (e.g., #2, #3, #10, #14) released in the HEXAGON folder, and dated Oct and Nov 1965, use the code name GAMBIT-CUBE or G-3. These are internal memos or comments on memos to the DNRO. "Gambit 1", "Gambit 2", and "Gambit 4" on the other hand might have indeed been "made up" later-on, or by an outside "observer" (like the KH-12, KH-13 designations?).

[Jim]

I have yet to go through the documents, but I suspect that this whole "Gambit 1" and "Gambit 3" stuff is actually created more by the NRO historians than the actual documents. A quick view of the documents indicates that they generally referred to the KH-7 and KH-8, as well as the KH-8B, etc. I'm certain that all of the imagery interpretation reports (and there were TONS of those produced) used those designations. And I suspect that the people working on the vehicles all generally used the KH designations and not "Gamibt 3," etc.

I think that the Oder/Worthman histories may have adopted that terminology and then the Haines' history from 1997 repeated it, and now the NRO's public affairs people used that in all of their press releases and documents.

But it won't be until I start doing interviews that I'll get a good sense of the common usage.

KH designations are used by the product users.  Code names are used by the people working on the systems

[Blackstar]

KH designations are used by the product users.  Code names are used by the people working on the systems

They weren't consistent about that. There are documents that used KH designations for Corona and then code names for the Gambit.

My impression is that they weren't consistent in their internal documentation--or at least did not become consistent until later (and then they were consistent in a confusing way!).

My bias is toward the KH designations because they're more orderly. But I still have not figured out if there was a KH-9A, KH-9B and KH-9C, or if they simply went by KH-9 Block 1, 2 and 3.

And to add to the confusion, the documents seem to indicate that there were several blocks of KH-7s, but the NPIC reports do not use KH-7A, B, C. However, there were also several blocks of KH-8, and we do know that there was a KH-8B.

I have to go through the docs closely and list the various designations.

[Art LeBrun]

I note that the Gambit 3 only had solar arrays from the 48th mission onwards, which means that flights up to 56 days were achieved purely with battery power.

Is this really possible for battery only? Since solar arrays were used as early as 1960/1961 on Midas why not with KH-8?

[Blackstar]

Is this really possible for battery only? Since solar arrays were used as early as 1960/1961 on Midas why not with KH-8?

The simple answer must be that the equipment did not require it. Midas needed to operate an electronic sensor for a longer time, whereas Gambit probably turned its film motors on and off for short periods of time.

[Art LeBrun]

Is this really possible for battery only? Since solar arrays were used as early as 1960/1961 on Midas why not with KH-8?

The simple answer must be that the equipment did not require it. Midas needed to operate an electronic sensor for a longer time, whereas Gambit probably turned its film motors on and off for short periods of time.

Maybe the excess capacity offered by Titan 3B and seemingly not used was taken up by major battery systems............

[jcm]

The histories do spend a lot of time discussing battery upgrades. I think they ended up with 10 batteries. Also true on CORONA, a lot of the mass growth in later variants was extra batteries, until they went to the solar panels.

[Blackstar]

I caught a snippet in the G history that said that they used some extra mass margin at one point to switch to heavier and more long-lasting batteries. I suspect they did this a number of times.

[Jim]

KH designations are used by the product users.  Code names are used by the people working on the systems

They weren't consistent about that. There are documents that used KH designations for Corona and then code names for the Gambit.

My impression is that they weren't consistent in their internal documentation--or at least did not become consistent until later (and then they were consistent in a confusing way!).

My bias is toward the KH designations because they're more orderly.

KH never shows up in contractor documentation or direction to the contractor. 

KH is an afterthought.  Also, there are more missions than just imagery and they don't have a KH designations.

[Blackstar]

1-KH never shows up in contractor documentation or direction to the contractor. 

2-KH is an afterthought.  Also, there are more missions than just imagery and they don't have a KH designations.

1-That's true, but it DOES show up in internal NRO documentation.

2-Yes, there are more missions than just imagery.

But there seem to be a lot of designation systems, and they're not all used consistently. For instance, there are vehicle mission designations, AF program numbers, etc.

[ChileVerde]

But there seem to be a lot of designation systems, and they're not all used consistently. For instance, there are vehicle mission designations, AF program numbers, etc.

Mission designations:  5500 for KENNAN, 2200 for post-Kennan, 7600 for RHYOLITE, 7500 for CANYON (?), 3100 for LACROSSE, etc., etc.  Is there a listing of the known or quasi-known ones?

[hoku]

Here are some more musings on the ground resolution (since the actual numbers have been redacted quite inconveniently):

Fig. 5 in The KH-8B Camera System (Doc #17 in the GAMBIT folder) visualizes the KH-8B primary camera (175.6" focal length) frame coverage, which results in a 3.4 nautical mile (6,300 meter) wide swath. Fig. 7 shows that the main image is projected on a 8.811" (223.8 millimeter) wide portion of the film. This yields a ratio of ground coverage to film width of 6,300 meter / 223.8 millimeter or 28.15 meter / millimeter.

The GAMBIT Story has a section on GAMBIT Films (page 85):
Developed by Kodak … these films evolved from the original Type 3404, through Type 1414 high-definition film, SO-217 high-definition fine-grain film, and a series of films called "mono-cubic dispersed" or "monodispersed,", on which silver-halide crystals were very uniform in size and shape, providing significantly improved film speed and resolution. SO-315 contained silver-halide crystals of the order of 1,550 angstrom units in dimension, in SO-312 the size was reduced to 1,200, and in SO-409 to 900 angstrom units.

Kodak's technical data for Type 3404 quotes a resolving power of 50 to 100 line pairs per mm. Hence with the lowest resolution film, KH-8B could have achieved a resolution as good as 30 to 60 cm (1 to 2 ft). Using a film with a resolution equivalent to Kodak's Type 3414 AERECON High Altitude Film with a resolving power of 320 to 630 line pairs per mm would have enabled KH-8B to sample a ground resolution of 5 to 10 cm (2 to 4"), i.e. in the same order as the best resolution of 2.3"(?) Dwayne heard about.

Does anyone know how silver-halide crystal size translates into resolving power (simply multiplying the size by a factor of 10 to 20, as suggested, e.g., here http://cool.conservation-us.org/coolaic/sg/emg/library/pdf/vitale/2009-10-vitale-filmgrain_resolution_v24.pdf)?