Today's photo is a large, rather faded color print of Lockheed EC-121R Constellation, 67-21486 (serial 1049A-4478), also known by its program name "Batcat", which was assigned to the 553rd Reconnaissance Wing.
With the combined cover of jungle, darkness of night, bad weather and traveling through neutral Laos, the North Vietnamese truck convoys traversing the Ho Chi Minh trail and penetrating into South Vietnam were nearly impossible to detect by the Americans. To overcome this obstacle, the highly classified IGLOO WHITE program, initially known as MUSCLE SHOALS and also known as "MacNamarra's Electronic Fence", was developed in 1967.
The idea was to create a long electronic barrier against NVA infiltration into the south. Long lines of small sensors (which looked and acted like oversized lawn darts) were dropped by OP-2E Neptunes and specially-equipped F-4 Phantoms, down through the jungle canopy, where they then stuck into the earth. There were a number of different types of sensors, from acoustic microphones to radio receivers to units that picked up the seismic signatures of trucks moving over the dirt roads. High overhead, an EC-121R Batcat from the 553rd would be orbiting, picking up the return signals from the sensors, and forwarding them on to the Infiltration Surveillance Center, operated by Task Force Alpha based at Nakhon Phanom Air Base in Thailand. Information gleened from this surveillance network would then be used to target strike aircraft.
The 553rd RW was stood up in 1967 to support IGLOO WHITE and was based at Korat AB, Thailand, and operated all 30 of the EC-121R BATCATS. The EC-121Rs were converted from Navy WV-2/EC-121K and EC-121P aircraft, both from in-service aircraft and planes repurposed on the assembly line (the airframe in our photo was originally a WV-2, BuNo 143204).
A Batcat mission flew with a crew of 17-19 and typically lasted 18 hours, which including 8-11 hours in orbit on station. There were 11 different orbits, all color-coded, and ranging from the Gulf of Tonkin to over Laos and Cambodia.
With the end of the winding down of the IGLOO WHITE program, the EC-121s were replaced by the optionally-manned, Beech 36-based UC-22 single-engine aircraft. Batcat 67-21486 was evidently transferred to the 388th Tactical Fighter Wing, also at Korat, for a short time before being sent to Davis-Monthan in Tucson (where our photo was taken), Arizona on 17 December 1970. The airframe was declared surplus on 18 May 1971 and was finally scrapped in May 1973.
Tip o' the hat to Brother Eric for giving me the photo!
Some pertinent links: