DEAR LENNY,

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP67B00511R000100190013-7
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 1
• Document Creation Date: November 16, 2016
• Document Release Date: February 10, 2000
• Sequence Number: 13
• Publication Date: June 12, 1963
• Content Type: LETTER

Approved For Rel W a 2000/05/04: CIA-RDP67B0Q 1 R000100190013-7
12 June 1963
Dear Lenny,
As you probably know, STATINTL
visited our plant to discuss the heat insulation and window aspects
of their systems. This is to report to you our concern about some
of the problems.
It is not appropriate to comment on the total technical
requirement on the window since it is not known what optical
degradation has been allowed in the overall tolerance apportionment.
While we are sure that this optiosl quality specification must be
"tight", no exact numbers were disoussed. It is therefore impossible
for us to decide if any proposed solution will permit the required
performance to be achieved.
However, we were able to point out two aspects which might
by their very nature preclude any fully satisfactory solution for
their system. First, the thermal gradient which must exist between
the film and the outside environment must be controlled in a satisfactory
manner. Second, that* is a theoretical wedge requirement on the outer
window which must be tempered by what is achievable in practice. This
wedge requirement arises because the lens aperture "looks" through at
least two adjacent window ports for each exposure.
Eecause of this glass wedge tolerance, it would perhaps
be unattractive to make the outer "skin" windows of a vacuum design
for heat insulation. Consequently, it appears to us that adjacent
thin outer window* should form the "skin" contour, and the thermal
barrier should be provided by a single internal vacuum (or other)
window in front of the lens, the. separating the two problems. This
possible "solution" ignores air wedge effects, which should be
analyzed in light of the previously mentioned tolerance apportionment.
The suggested configuration should not be considered as a recoumaendntion
in the absence of a detailed analysis.
We hope the visit has helped you with this program. If
we can be of further assistants, please let us know.
zest regards
mb
be : JP/ELT ~/
CMH
PFF
Approved For Release 2000/05/04: CIA-RDP67BOO511 R000100190013-7