KH-11 KENNEN

[Blackstar]

Years ago I've been told by a colleague 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 reply as it 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.

There may be some truth to it.

Way back in the mid-1980s or so I remember reading an article that ran in a scientific publication. May have been Scientific American, and I could/should go search on Lexis to see if I can find it.

What I distinctly remember was that the reporter visited Perkin-Elmer, which built the Hubble mirror. The article was written either before they had built the mirror, or as they were in the process of making it (you'll remember that they screwed it up). The manager said something along the lines that the contract had enabled them to build a facility where they could construct larger mirrors and this (paraphrasing, but I don't think by much) "would make them competitive for other projects." He was enthusiastic about that.

At the time I filed that away in my brain because it told me that P-E was NOT ALREADY making Hubble-size mirrors, and that meant that whoever was making the big mirrors for the KH-11 was not P-E (whose mirrors for the KH-9 were smaller). It was obviously Kodak.

I really need to find that article.

[Blackstar]

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.

I think France has a similar law and theirs is more restrictive than the U.S.

[Star One]

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.

I think France has a similar law and theirs is more restrictive than the U.S.

Germany is the most liberal in this respect.

[Melt Run]

There may be some truth to it.

Way back in the mid-1980s or so I remember reading an article that ran in a scientific publication. May have been Scientific American, and I could/should go search on Lexis to see if I can find it.

What I distinctly remember was that the reporter visited Perkin-Elmer, which built the Hubble mirror. The article was written either before they had built the mirror, or as they were in the process of making it (you'll remember that they screwed it up). The manager said something along the lines that the contract had enabled them to build a facility where they could construct larger mirrors and this (paraphrasing, but I don't think by much) "would make them competitive for other projects." He was enthusiastic about that.

At the time I filed that away in my brain because it told me that P-E was NOT ALREADY making Hubble-size mirrors, and that meant that whoever was making the big mirrors for the KH-11 was not P-E (whose mirrors for the KH-9 were smaller). It was obviously Kodak.

I really need to find that article.

The Hubble contract actually goes back to the 70ties. Please find photo of the PE mirror in process in the enclosed photo dated 1979.
I believe PE, EK and ITEK all produced 2.4 meters for the "customer" in the 70ties. EK produced the Hubble spare which is in the Smithsonian. A 2.4 that ITEK built in the 70ties has become the PM for the Magdalena Ridge observatory.

[gosnold]

What about ITT? When did it start building mirrors for the NRO?

[Melt Run]

What about ITT? When did it start building mirrors for the NRO?

ITT bought EK. I'd have to refresh my memory as to exactly (2004) when but only the names have changed.

[mgfitter]

Slightly OT perhaps, but do they still build such things today, or have these monolithic mirrors become old technology these days?

-MG.

[kevin-rf]

Two 2.4 m mirrors from the canceled Boeing KH-11 successor (FIA-I) just got donated to NASA, and USA-245 (a KH-11) was launched in august. So Yes*

*Maybe... Some have indicated once the last KH-11 was launched (believed to be USA-245) Lockheed was going to do a new replacement of unknown design.

[dasmoth]

I believe PE, EK and ITEK all produced 2.4 meters for the "customer" in the 70ties.

This is intriguing.  We don't see this kind of redundancy in earlier KH programs, at least when going on the published histories.  Any idea why three contractors were making apparently similar mirrors in this case?  Worry that someone would fail when making such a big mirror?  Concern about getting a high enough production rate to match early projections of flight rate?

[kevin-rf]

Well, One doesn't just make a 2.4m mirror... It can be a multi-year process. I wonder if multiple vendors was a capacity or the customer not being satisfied with the progress the vendors where making.

[Melt Run]

I believe PE, EK and ITEK all produced 2.4 meters for the "customer" in the 70ties.

This is intriguing.  We don't see this kind of redundancy in earlier KH programs, at least when going on the published histories.  Any idea why three contractors were making apparently similar mirrors in this case?  Worry that someone would fail when making such a big mirror?  Concern about getting a high enough production rate to match early projections of flight rate?

It can all be attributed to development. In the late 60ies to mid 70ties such mirrors had not been built. Remember the first Palamar mirror broke. In the early days the optimum mirror material, fusion technique, mirror geometry. Thermal or fretting, temperature, duration, heating and cooling rates, inclusions, inspection, testing, polishing materials, lap sizes and materials, polishing rates mirror handling and a lot more was all TBD. Believe me there were a lot more mirrors then the three noted above. There was a massive learning period.
BTW large mirrors today hold little resemblance to the Hubble mirror in construction.
Thanks for the memories

[Blackstar]

New issue of Aviation Week.

[gosnold]

That's WorldView 3. The aperture is too small to be a KH-11.

[Star One]

That's WorldView 3. The aperture is too small to be a KH-11.

I know I released when I saw that they were Ball Aerospace workers, plus of course the headline helped.

[Targeteer]

There is some interesting reporting/informed speculation on page 58--can't get a direct link--that USA-193 had a multi- or hyper-spectral payload that was blasted into pieces by an SM-3 apparently due to a failed safe hold mechanism...

[Star One]

There is some interesting reporting/informed speculation on page 58--can't get a direct link--that USA-193 had a multi- or hyper-spectral payload that was blasted into pieces by an SM-3 apparently due to a failed safe hold mechanism...

What's a safe hold mechanism?

[Blackstar]

That's WorldView 3. The aperture is too small to be a KH-11.

Thanks. I had no idea.

[kevin-rf]

Huh? I thought USA-193 was widely believed to be a radar and not an optical imaging sat. A 58 degree orbit is more typical of known lacross radar satellites, though the latest generation (FIA-R) seem to be opting for retrograde orbits.

[Targeteer]

There is some interesting reporting/informed speculation on page 58--can't get a direct link--that USA-193 had a multi- or hyper-spectral payload that was blasted into pieces by an SM-3 apparently due to a failed safe hold mechanism...

What's a safe hold mechanism?

Provides basic vehicle control and communications in case of a problem.  The story repeats previous reporting that an almost identical system on SBIRs had to be redesigned causing a lengthy launch delay.

[Targeteer]

That's WorldView 3. The aperture is too small to be a KH-11.

Thanks. I had no idea.

Do I sense a bit of sarcasm   You're stunned they wouldn't display a current NRO bird on the cover of Av Leak?  Now I'm being sarcastic and no, I have not forgotten the image they printed widely reported to be a Lacrosse radar bird minus the antenna--the key element.