[rlmorel]

Are these the guys?

I guess if it was secure comlink from that type, the mission that might fit would be these guys? (From the hated Wikipedia)

RB-57E
Though intended as a bomber and never before deployed by the USAF to a combat zone, the first B-57s to be deployed to South Vietnam were not operated in an offensive role. The need for additional reconnaissance assets, especially those capable of operating at night, led to the deployment of two RB-57E aircraft on April 15, 1963. Under project Patricia Lynn these aircraft provided infrared coverage using their Reconofax VI cameras.[5] Later in August 1965, a single RB-57F would be deployed to Udon, RTAB in an attempt to gather information about North Vietnamese SAM sites, first under project Greek God and then under project Mad King. In December another RB-57F would be deployed for this purpose, under project Sky Wave. Neither project garnered useful results and they were terminated in October 1965 and February 1966 respectively.

Would these be them?

(LOL, I know YOU know the answer, I am just being rhetorical...:)

[TXnMA]

Yep, RB-57Fs. That "now in service" msg also included the (classified back then) service ceiling -- 80K+ feet. Now published as 82Kft. Just watched a U2 flight video; they made a big deal out of flying at 70K ft...

Curiously, when I got back home from overseas, I learned that my father-in-law had worked on the conversion at General Dynamics in Fort Worth. He said those big turbofans they stuck in those extended wings were so big you could nearly stand in the inlet...

Some of the A/C he worked on: B-24, B-36, B-47, B-58, RB-57F, FB-111 & F-16 (that I recall.)