D-Day was the boldest, riskiest and most anticipated operation of the entire World War II European Theater. To succeed in the Allied invasion of France, Allied commanders needed detailed information about prospective French coastal landing sites and surrounding areas. The entire outcome of the war rested on this invasion, the long-awaited massive first step to liberate occupied France and the rest of occupied Europe.

By early 1944, the Allies nearly ruled the skies, having pushed most of the Luftwaffe air operations back into Germany, and were able to photograph all pertinent shoreline and adjacent areas almost at will, though still subject to fierce anti-aircraft fire. While fighters escorted bombers ever further into Germany to destroy military, industrial, transportation, and communication targets, American and British aerial reconnaissance (recce) missions provided millions of photographs detailing every aspect of the forthcoming invasion sites and the German defenses along the beaches of northern France.

In contrast, Allied air superiority limited the German Luftwaffe reconnaissance missions over England to see only what the Allied command wanted them to see. So, while the invasion forces, equipment, and supplies built up, under camouflage, in southern England in the spring of 1944, German reconnaissance aircraft were carefully “allowed” to photograph a fictitious invasion build up in southeast England, presumably aimed at Calais, the closest French soil across the English Channel.

American and British reconnaissance flights concentrated on the true invasion area, the beaches of Normandy beyond Le Harve, and more than 200 hundred miles west of Calais. Aerial photography was combined with code-breaking, spying, French resistance reports, and other intelligence sources to direct an extraordinarily complex plan and enable the successful execution of a massive invasion two years in the making. Though the invading forces would not encounter the heart of the German military machine in this part of coastal France, commanders still anticipated a strong defense that required a swift and disciplined assault to clear the way for the huge influx of troops and equipment.

The National Air and Space Museum Archives contains a small but intriguing batch of aerial photographs taken in the days and hours before, during, and after the D-Day invasion. Curiously, the exact image locations are not included but the images clearly tell the story. The donor, Captain Samuel L. Batchelder, a photo interpretation officer in the U.S. Army Air Forces, was stationed at the Allied Central Interpretation Unit (CIU) based at Danesfield House, Royal Air Force (RAF) Medmenham, England. RAF Medmenham was the primary intelligence and interpretation center for the European and Mediterranean theaters. There interpreters practiced their science of identifying objects in images, analyzing the information before them, and map-making.

The photographs analyzed by Batchelder and others came from sources based across England, such as:

• The RAF Photographic Reconnaissance unit at RAF Benson air base, also the home of the No. 542 Squadron Group RAF, which flew camera-equipped Supermarine Spitfire Vs and deHavilland Mosquitos.
• The USAAF Eighth Air Force Command was close by at RAF High Wycombe
• The 7^th Photographic Reconnaissance Group, the “Eyes of the Eighth,” stationed at Mount Farm adjacent to RAF Benson, flying Lockheed F5As, the photographic version of the Lockheed P-38
• The 10^th Reconnaissance Group of the Ninth Air Force and others.

Photographic laboratory personnel at the bases processed vast quantities of exposed film and printed photos for initial assessment and distribution to fighter and bomber pilots for identification of their forthcoming targets. The best negatives then went on to the Central Interpretation Unit for deeper analysis and retrieval of a wide range of military (strategic and tactical), industrial, and geographic information.

The F5 carried a variety of cameras, including a configuration of five Fairchild K-17s with one oblique (or side) view camera on each side of the aircraft nose, two vertical cameras that created a stereoscopic view of the ground, and one forward vertical camera for mapping. Another configuration, the K-17 trimetrogon, was actually three cameras, two oblique and one vertical, in one casing that provided a panoramic view from horizon to horizon. F5s also carried the new Sonne camera with a synchronizing mechanism that matched the speed of the film as it moved across an open slit to the aircraft’s ground speed, producing a continuous strip of sharply focused imagery.

With increasingly longer focal length lenses and high-altitude film in a variety of cameras, recce pilots could fly at higher, and safer, altitudes of 30,000 feet and still record sharply focused images. However, the acquisition of precise landing beach conditions, such as low tide views of placement of German defense obstacles designed to thwart troop and equipment landings, required extremely dangerous low-level “dicing” missions at an altitude of only 15 feet!

These stunning low-tide images show antitank barriers with steel prongs in zigzag placement and rows of barbed wire not visible at high tide. Others revealed the concrete blocks, steel scaffolding, minefields, pillboxes, and heavy artillery that awaited the amphibious invasion forces. Preparation for these impediments was vital.

Colonel (later General) George Goddard, USAAF, was one of the architects of military aerial photography between World War I and World War II. He noted another intriguing imagery value: Aerial photography was now being conducted on a twenty-four hour basis using every available photographic airplane in England, and many stereoscopic shots of the beaches and their defenses were made. From these photographs exact models were constructed so that our troops could be trained in techniques to capture the real thing.

Stereo pairs of images, side by side offset images, viewed through a stereoscope provided three-dimensional information and the basis for 3-D modeling. According to Captain Batchelder, the CIU built 97 precise topographic models – contoured cardboard cutouts covered in rubber and topped with the actual images of beach or terrain locations. Trial runs bred familiarity and ensured the steady movement of men and equipment over the beaches.

Goddard summed up the June 6 action:

On D-Day I visited two of our busiest reconnaissance activities and marveled at their tremendous activity. Recce airplanes were landing and taking off continually. The crews were dashing into the photographic laboratories with their freshly exposed film magazines, and messengers were rushing to the Intelligence department with armfuls of aerial photographs. Around the clock thousands of photographs were being produced and without a hitch in the entire operation.

We have a sample of those photographs in our Archives:

In the performance of his duties as a Photo Interpreter (PI) at Medmenham, Batchelder assisted with the vital assessment of thousands of photographs shot on British and American photo flights. When he returned to the U.S. shortly after VE Day in April 1945, enroute to the Pacific Theater, he brought home with him these and other photographs, dramatic images of Operation Neptune and Overlord, the D-Day invasion mission names. The war ended before he reached the Pacific.

The tremendous impact of aerial photography acquisition and interpretation on the D-Day invasion followed and preceded many other critical wartime intelligence achievements. For example, only months earlier, the brilliant CIU photo interpreter Constance Babington Smith, scrutinizing northern Germany coastal images, identified the Nazi V-1 missile site. Although the first military reconnaissance flights with cameras began only 30 years earlier in World War I, and its value was still unappreciated by all commanders at the start of World War II, it is clear that by the end of the war, aerial photography had become essential eyes of the military.