The last 15 RB-47E aircraft on order were completed as RB-47Ks. They differed from the RB-47E in being equipped for both weather and photographic reconnaissance missions at all altitudes. In addition to the standard set of cameras installed on the RB-47E, the K model high-resolution and side-looking radars for weather data gathering. In addition, air sampling equipment was provided that could be used to test the atmosphere for radioactive fallout. The first RB-47K was delivered in December of 1955.
The RB-47K was basically an airborne weather information gathering system They were operated by the 338th SRS, 55th Strategic Wing, and flew all over the world gathering weather data for SAC and sampling the radioactive fallout from foreign nuclear tests. They were phased out in the early 1960s.