Commando Hunt III
The image is taken from a report describing operations in the Commando Hunt III interdiction programme (HQ 7th Air Force 1970). It is a vertical aerial photograph; it shows a blanched, cratered earth and scorched tree trunks; a road arcs from top-middle out to the left of the frame. A truck, a type often used by North Vietnamese supply forces, is visible on the roadway. What might be smoke rises from the truck--a dense, cloudy white patch drifts leftward and diffuses over darker terrain. Due to the degraded quality of the photograph, it is difficult to ascertain one way or another, although the context of surrounding devastated landscape and indeed the content of the report itself might suggest a "successful" strike. In the bottom right of the image, the silhouette of the aircraft taking the photograph is visible.
Photography served multiple purposes at various points in the electronic barrier system. Speculative surveillance sorties investigated sections of the trail network, recording new routes, the locations of truck parks, and any signs of active movement. In order to improve hitherto unreliable data regarding the positioning of sensors, emplacement aircraft were fitted with a camera that automatically took a photograph at the moment of releasing a sensor. Although this reportedly contribted to a substantial increase in emplacement accuracy, this meant that sensor seeding missions had to be carried out during the day in order to get clear images of the terrain (Caine 1970, 26). Finally, photography played an important role in quantifying the effects of an airstrike. Following a bombing run, surveillance aircraft surveyed target locations, recording destroyed vehicles and damaged infrastructure. Most of this imagery would flow back to the Infiltration Surveillance Centre at Nakhon Phanom, where it was subsequently collated, analysed, and tallied for reports by Task Force Alpha's photo interpreters.
As such, the manual practice of photographic interpretation and its various tacit techniques of scrutinising and assigning underpins the whole process of the electronic barrier, from sensor emplacement to target assessment. Yet, gathering such photographic material was not straigtforward. Attempts to verify strikes on trucks were often undermined because "reported locations of strikes were not precise" and "jungle canopy, weather, and enemy defences restricted post-strike reconnaissance" (HQ 7th Air Force 1970, 50). The document also suggests that damaged or destroyed trucks were "removed or camouflaged" by the enemy (1970, 50). Ultimately, "nine per cent of the trucks reported destroyed or damaged were confirmed by photography" (1970, 50). The statistics extrapolated from such reconnaissance missions were only based on a partial survey, with omissions in the data filled in with statistical techniques such as regression analysis. Interdiction figures reported by the Air Force were met with scepticism by some in government at the time--a1971 Senate subcommittee report into the electronic barrier stated "truck kills claimed by the Air Force last year greatly exceeds the number of trucks believed by the Embassy to be in all of North Vietnam" (Edwards 1997, 4).