On Aug 26, 2011, at 7:10 PM, Joseph McAllister wrote: > > On Aug 26, 2011, at 10:17 , John Francis wrote: > >> On Fri, Aug 26, 2011 at 10:14:02AM -0400, Mark Roberts wrote: >>> Tom Cakalic wrote: >>> >>>> http://www.space.com/12707-earth-photo-moon-nasa-lunar-orbiter-1-anniversary.html/?utm_source=Newsletter&utm_medium=Email&utm_campaign=SP_08252011_1 >>> >>> They have one of those beasts on display at the George Eastman House >>> in Rochester. Truly impressive piece of kit! >> >> In the article quoted above, reference is made to a precursor to that >> system, although Kodak partner there is said to be Boeing, rather than >> Lockheed (Kodak's co-developer of the "Keyhole" satellite spy cameras). >> I've seen one of those on one of the last (and extremely rare) open days >> at the Onizuka Air Force Station (a.k.a. "The Blue Cube") in Sunnyvale. >> >> That system had a rather simpler way of getting the images back to earth >> (though one that was not available to a lunar mission) - the exposed film >> was ejected from the satellite and parachuted back to earth. It was then >> captured in mid-air by a specially modified C130. > > That was replaced by the "Talent-Keyhole" system that came to life in 1976. > Basically a Hubble that was pointed towards the earth (although we did once > point it at a post-Challenger shuttle flight as a precursor to in flight > inspections, but that didn't work very well. Too much spectral glare off the > white parts of the shuttle.) The TK birds imaged via 3 CCD sensor "strips" > with overlapping coverage ( _—_ ) digitally sequenced so they appeared as one > long strip. The digital data could be received in real time by sending the > signal to a series of relay satellites and ground stations (Alice Springs AU > is one) before arriving home in Virginia. > > There the 2.4 GHz signal was sent via waveguides (old fashioned) from the > golf balls containing 20 meter antennae into the facility where it was > chopped into quarters (early on) and processed by four IBM 360 (later two IBM > 3090s) and cabinet after cabinet after cabinet of custom decription racks, to > be simultaneously fed to A: four 48 track 70mm tape recorders that were good > for 12 minutes each with their 24 inch pyrex glass reels threaded like 9 inch > was, with 4 foot vacuum buffers on either side of the record head. B: about > 36 units of hard disc recorders that took 12 platters packs (later on, only > the tape for the first few years) and C: four Laser Image Reconstructors > (LIRs) which were basically souped up LaserWriters each of which would write > on 9" negative film stock a quarter of each image at 2100 LPI. Later on, we > cut the number of LIRs to two, as progress allowed them to image the pass in > almost real time, using the hard discs as buffers, on one long strip of 5" > film. > > These rolls of film was processed through four of the six huge 30 plus foot > long EK processors that spread 100 degree "gorp" developer (very heavy > viscosity) onto the film using a knife edge feed trough for 7 to 14 seconds > developing time (9 avg) followed by pretty normal chemicals after that, > except the stop was a bit hotter, and the "gorp" was scraped off the film > first by another knife edge and the fixer was very alkaline (8.x). Later, of > course, only one machine was used to process the original. But early on the 4 > original negtative rolls were contact printed to positive stock once dry, and > the positive stock was contact printed to get a duplicate negative. > > Using the dupe originals, the rolls were fed into a machine that cut and > aligned the images from the each of the resulting 4 rolls of film so they > could could be sonically welded into one finished image. It would also > package them in clear vinyl sleeves on which was dot matrix printed in bright > purple ink all the codes for the contents which were read by the another > machine which assembled the correct sets of film for distribution to various > customers around the world.
Interesting story. I learned about the film drop in my SI-TK in-brief, but basically I just noted that images were acquired, film dropped and recovered and developed. At that point I and colleagues came into the picture, working on best techniques for training analysts to do effective interpretation. What is truly fascinating to me is how much of our space program and spin-off technologies were driven by what are ultimately unreasonable demands by policy makers for certainty. One of my all-time-favorite reads was Perception, Deception, and Surprise [http://www.amazon.com/Perception-Deception-Surprise-Case-Kippur/dp/B000QBA9U4/ref=sr_1_1?ie=UTF8&qid=1314405274&sr=8-1] written by an Israeli intelligence officer after the Yom Kippur War. Brief summary: stuff happens. You can't and won't know what/when it will happen. Learn to live with it. stan -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
