The Photo Interpreters of the 548th RTG era did not have the luxury of digital imagery and high speed computers to assist them.  In about 1980, Photo Interpreters became Imagery Interpreters, since they now worked with more than photos, it was becoming a digital world.  Many of the items that were included in the PI Kits of those days are probably not found today.  Here is a look at what we used to do the mission.

A pair of 9-inch Italian scissors (which we nicknamed "Excalibur") for cutting up film, a yellow Skilcraft-US government grease pencil for marking film, an actual slice of film, emblazoned with the 548th insignia, on an equipment repair request form, we kept the maintenance people busy reparing our light tables.  (Photo and narrative courtesy of Allen Marsh)

The PI Slide Rule.  One side was a standard slide rule, which you learned to use in PI school, but probably forgot as soon as you graduated.  The other side was the PI side, which any PI worth his salt knew how to use.  It could be used for mission planning to calculate intervalometer settings and other data, which most seldom used.  It's main function was to determine the size of an object and the scale of the imagery.  You could put in the altitude of the aircraft and focal length of the camera, to give you a scale, or measure a know object and put in that measurement and the know size of the object.  It quickly got you in the ball park.  Today you just move the cursor and it does the work for you.  A little publicized extra of the slide rule is the PI was allowed to take it with him into the room when he took the Speciality Knowledge Test (SKT) for promotion.  The admin guys running the test had no idea what it was or what it was suppose to have on it, so the PI's would paste their formulas and other data neatly on the slide rule and did not have to burn up brain cells remembering them.
The Stereo Scope.  Although not widely used at the 548th due to the availability of Baush and Lomb Zoom 240 and 500 stereo optics on the light tables, the stereo scope was a mainstay of the tactical PI, with the four power scope being the weapon of choice; the 2X scope was mainly good for viewing prints or other low resolution images.  In Southeast Asia, the PI's found that by taking the nut off the end of the scope, they could spread them far enough to see KS-72 frames in stereo, this made for more than a few headaches.  The later PI kits introduced in the mid-70's had a stereo scope that was dual 2X and 4X, they were not the greatest pieces of equipment.  When the old kits were turned in, all supply wanted was the PI kit box, they did not care what was in it, so the resourceful PI's stocked their desks with the old equipment.

Dividers.  The PI kit came with three dividers, The proportional dividers were a great idea, but seldom used by the PI, unless he could not find his two points.  The two point dividers were great for getting distances and other tasks.  The ten points were also a handy device, 50 Series charts only had minute marks ever five minutes, so if you did not have one of the geo coordinate templates that were locally made, you could use the 10 points to get a ball park coordinate.  They also made good weapons in a gang fight.
Tube Magnifier.  The tube magnifier is what the the PI used when he was scanning, if he spotted a suspicious looking blob, he could size it up with his lupe, if it looked promising, it then went under the Zoom 240 for a closer look.  The PI kits in the 70's came with a variable power tube magnifier, which was the size of a hand grenade, not the best thing to use on a long scan, so the 7X lube remained the weapon of choice.  The tube magnifiers also had a reticle for measuring, the wise PI would take it off and use it under the Zoom 240 to get things down to a gnat's rear end.
The Navigational Plotter and Box Wood Scale.  The navigational plotter, better know as the Weems Plotter, was handy for getting bearings and in mission planning.  At the 548th it generally served as a straight edge.  The box wood scale was good for measuring longer distances and bigger objects, rarely did the scale we worked with allow us to use it.

The MK-6B Dead Reckoning Computer.  In PI school you learned to use this monster, but generally did a brain dump on it when you left school.  It came with the earlier PI kits, but the newer kits did not have it.  I remember MSgt Jimmy Rogers saying he was on a United Flight and calculated the Halfway to Hawaii Game using it and won, he must have impressed those seated around him.

The Light Table.  The light table was the mainstay of the PI until we went digital.  This is a Richards MIM-4 with a BL Zoom 500, on the left, too high tech for some, many of us preferred the older MIM-3 and Zoom 240, on the right.  The MIM-3 also had a slit and rollers in the middle, which, along with four motors, allowed you to mount two rolls of film on the table for stereo or comparison viewing.  You could either use roll film or chips with the both light tables.  When using rolls, you could tell the experienced PI's, they would rewind the film at full speed across the table and then switch it off and get only one turn on the roll once the end of the film was reached.  They also had a switch for the direction of the motor, it you had it switched wrong, you wound up with film across the floor.

The Handy Book.  Although not included in the PI kit, McDonnell Douglas put out a fine little pocket size booklet that had just about everything a PI needed to know in it, from all of the formulas you never used, to how big a tennis court is so you could use it for scaling imagery.

Another item not included in the PI kit, but was taught at the school house, was the code matrix block cheat sheet.  The RF-4C recorded data in a very small block in binary code on each image, you need a magnifier to read the data.  It included information on the date, unit, sensor, aircraft altitude, heading, pitch, roll, zulu time, geographic coordinates, and other information.  This was not something we used at the 548th, but is included here for historical purposes.

The following photos are of imagery collection platforms and equipment taken by Mark Olson at National Air and Space Museum Steven F. Udvar-Hazy Center near Dulles Airport, outside Washington D.C.:




Photo of the Corona Film Capsule outside of the display case, 

 Roger Guillemette, SPACE.com Contributor

Date: 18 September 2011 Time: 09:03 AM ET

The massive KH-9 Hexagon spy satellite on display at the Smithsonian National Air & Space Museum's Udvar-Hazy Center, after being declassified on Sept. 17, 2011. Longer than a school bus at 60 feet in length and weighing 30,000 pounds at launch, 20 KH-9 Hexagons were launched by the National Reconnaissance Office between 1971 and 1986.

CHANTILLY, Va. – Twenty-five years after their top-secret, Cold War-era missions ended, two clandestine American satellite programs were declassified Saturday (Sept. 17) with the unveiling of three of the United States' most closely guarded assets: the KH-7 GAMBIT, the KH-8 GAMBIT 3 and the KH-9 HEXAGON spy satellites.

The vintage National Reconnaissance Office satellites were displayed to the public Saturday in a one-day-only exhibit at the Smithsonian National Air and Space Museum's Udvar-Hazy Center at Dulles Airport, Va. The three spacecraft were the centerpiece of the NRO's invitation-only, 50th Anniversary Gala celebration held at the center last evening.

Saturday's spysat unveiling was attended by a number of jubilant NRO veterans who developed and refined the classified spacecraft and its components for decades in secret, finally able to show their wives and families what they actually did 'at the office' for so many years. Both of the newly declassified satellite systems, GAMBIT and HEXAGON, followed the U.S. military's frontrunner spy satellite system CORONA, which was declassified in 1995. [See photos of the declassified U.S. spy satellites]

This National Reconnaissance Office released graphic depicts the huge HEXAGON spy satellite, a Cold War era surveillance craft that flew reconnaissance missions from 1971 to 1986. The bus-size satellites weighed 30,000 pounds and were 60 feet long.
CREDIT: NRO

Big spy satellites revealed

The KH-9 HEXAGON, often referred to by its popular nickname "Big Bird," lived up to its legendary expectations. As large as a school bus, the KH-9 HEXAGON carried 60 miles of high resolution photographic film for space surveillance missions. 

Military space historian Dwayne A. Day was exuberant after his first look at the KH-9 HEXAGON.

"This was some bad-ass technology," Day told SPACE.com. "The Russians didn't have anything like it."

Day, co-editor of "Eye in the Sky: The Story of the CoronaSpy Satellites," noted that "it took the Soviets on average five to 10 years to catch up during the Cold War, and in many cases they never really matched American capabilities."

Phil Pressel, designer of the HEXAGON's panoramic 'optical bar' imaging cameras, agreed with Day's assessment.

"This is still the most complicated system we've ever put into orbit …Period."

The HEXAGON's twin optical bar panoramic mirror cameras rotated as the swept back and forth as the satellite flew over Earth, a process that intelligence officials referred to as "mowing the lawn."

Phil Pressel, one of the developers of the KH-9 Hexagon's panoramic camera system, proudly points out some of the spacecraft's once highly-classified features, a life's work that he had been unable to discuss publicly until the NRO's Sept. 17, 2011 declassification of the massive spy satellite.
CREDIT: Roger Guillemette/SPACE.com

Each 6-inch wide frame of HEXAGON film capturing a wide swath of terrain covering 370 nautical miles — the distance from Cincinnati to Washington — on each pass over the former Soviet Union and China. The satellites had a resolution of about 2 to 3 feet (0.6 to nearly 1 meter), according to the NRO.

According to documents released by the NRO, each HEXAGON satellite mission lasted about 124 days, with the satellite launching four film return capsules that could send its photos back to Earth. An aircraft would catch the return capsule in mid-air by snagging its parachute following the canister's re-entry.

In a fascinating footnote, the film bucket from the first KH-9 HEXAGON sank to the bottom of the Pacific Ocean in spring 1972 after Air Force recovery aircraft failed to snag the bucket's parachute.

The film inside the protective bucket reported contained high resolution photographs of the Soviet Union's submarine bases and missile silos. In a daredevil feat of clandestine ingenuity, the U.S. Navy's Deep Submergence Vehicle Trieste II succeeded in grasping the bucket from a depth of 3 miles below the ocean.

Hubble vs. HEXAGON

Former International Space Station flight controller Rob Landis, now technical manager in the advanced projects office at NASA's Wallops Flight Facility in Virginia, drove more than three hours to see the veil lifted from these legendary spacecraft.

Landis, who also worked on NASA's Hubble Space Telescope program, noticed some distinct similarities between Hubble and the huge KH-9 HEXAGON reconnaissance satellite.

"I see a lot of Hubble heritage in this spacecraft, most notably in terms of spacecraft size," Landis said. "Once the space shuttle design was settled upon, the design of Hubble — at the time it was called the Large Space Telescope — was set upon. I can imagine that there may have been a convergence or confluence of the designs. The Hubble’s primary mirror is 2.4 meters [7.9 feet] in diameter and the spacecraft is 14 feet in diameter. Both vehicles (KH-9 and Hubble) would fit into the shuttle's cargo bay lengthwise, the KH-9 being longer than Hubble [60 feet]; both would also fit on a Titan-class launch vehicle."

The 'convergence or confluence' theory was confirmed later in the day by a former spacecraft designer, who declined to be named but is familiar with both programs, who confided unequivocally: "The space shuttle's payload bay was sized to accommodate the KH-9."  [Infographic: NASA's Space Shuttle from Top to Bottom]

The NRO launched 20 KH-9 HEXAGON satellites from California's Vandenberg AFB from June 1971 to April 1986.

The HEXAGON's final launch in April 1986 — just months after the space shuttle Challenger explosion — also met with disaster as the spy satellite's Titan 34D booster erupted into a massive fireball just seconds after liftoff, crippling the NRO's orbital reconnaissance capabilities for many months.

A side view of a KH-7 GAMBIT spy satellite on display at the Smithsonian National Air and Space Museum's Udvar-Hazy Center at Dulles Airport, Va., on Sept. 17, 2011.
CREDIT: Roger Guillemette/SPACE.com

The spy satellite GAMBIT

Before the first HEXAGON spy satellite systems ever launched, the NRO's GAMBIT series of reconnaissance craft flew several space missions aimed at providing surveillance over specific targets around the world.

The  satellite program's initial system, GAMBIT 1, first launched in 1963 carrying a KH-7 camera system that included a "77-inch focal length camera for providing specific information on scientific and technical capabilities that threatened the nation," according to an NRO description. A second GAMBIT satellite system, which first launched aboard GAMBIT 3 in 1966, included a175-inch focal length camera.

 The GAMBIT 1 series satellite has a resolution similar to the HEXAGON series, about 2 to 3 feet, but the follow-up GAMBIT 3 system had an improved resolution of better than 2 feet, NRO documents reveal.

The GAMBIT satellite program was active from July 1963 to April 1984. Both satellites were huge and launched out of Vandenberg Air Force Base.

The satellite series' initial version was 15 feet (4.5 m) long and 5 feet (1.5 m) wide, and weighed about 1,154 pounds (523 kilograms). The GAMBIT 3 satellite was the same width but longer, stretching nearly 29 feet (9 m) long, not counting its Agena D rocket upper stage. It weighed about 4,130 pounds (1,873 kg).

Unlike the follow-up HEXAGON satellites, the GAMBIT series were designed for extremely short missions.

The GAMBIT 1 craft had an average mission life of about 6 1/2 days. A total of 38 missions were launched, though 10 of them were deemed failures, according to NRO documents.

The GAMBIT 3 series satellites had missions that averaged about 31 days. In all, 54 of the satellites were launched, with four failures recorded.

Like the CORONA and HEXAGON programs, the GAMBIT series of satellites returned their film to Earth in re-entry capsules that were then snatched up by recovery aircraft. GAMBIT 1 carried about 3,000 feet (914 meters) of film, while GAMBIT 3 was packed with 12,241 feet (3,731 meters) of film, NRO records show.

The behemoth HEXAGON was launched with 60 miles (320,000 feet) of film!

This image shows the flight profile for the NRO's GAMBIT 3 spy satellite missions between 1966 and 1984. The program was declassified in Sept. 2011.
CREDIT: NRO

HEXAGON and GAMBIT 3 team up

During a media briefing, NRO officials confirmed to SPACE.com that the KH-8 GAMBIT 3 and KH-9 HEXAGON were later operated in tandem, teaming-up to photograph areas of military significance in both the former Soviet Union and China.

The KH-9 would image a wide swath of terrain, later scrutinized by imagery analysts on the ground for so-called ‘targets of opportunity.' Once these potential targets were identified, a KH-8 would then be maneuvered to photograph the location in much higher resolution.

"During the era of these satellites — the GAMBIT and the HEXAGON — there was a Director of Central Intelligence committee known as the 'Committee on Imagery Requirements and Exploitation' that was responsible for that type of planning," confirmed the NRO's Robert McDonald, Director of the Center for the Study of National Reconnaissance.

NASA's Rob Landis was both blunt and philosophical in his emotions over the declassification of the GAMBIT and HEXAGON programs.

"You have to give credit to leaders like President Eisenhower who had the vision to initiate reconnaissance spacecraft, beginning with the CORONA and Discoverer programs," Landis said. "He was of the generation who wanted no more surprises, no more Pearl Harbors." 

"Frankly, I think that GAMBIT and HEXAGON helped prevent World War III."