Primary Role: Strategic Reconnaissance
From an early date, the Boeing C-135 was recognized as an excellent airframe for various special missions. One of these was strategic reconnaissance, using the aircraft’s capacious cabin to house large amounts of electronic equipment. Designated RC-135, these aircraft can be detached on a global basis to cover areas of the world where intelligence-gathering is required.
Several RC-135 versions are currently in service. Among these are three dedicated to general Signals Intelligence (Sigint) gathering. All feature large amounts of electronic recording and analyzing equipment on board, and have many aerials on the airframe, including slab-sided cheek fairings where many of the side-facing antennas are grouped. These serve the Automatic Elint Emitter Locator System (AEELS), which gathers signals from across the frequency spectrum, sifts out those of particular interest and relays data to operator stations in the cabin.
RC-135U “Combat Sent”
Two aircraft are designated RC-135U and are characterized by cheek fairings and additional fairings in the chin, boomer, wingtip, tailcone and fin-top positions. Until 1991 they were fitted with “towel rail” antennas above the cheek fairings, but these have been removed. The RC-135Us are believed to have special purposes within the Sigint fleet, and may also be used to trial new equipment.
RC-135V/W “Rivet Joint”
Eight aircraft are designated RC-135V, while six are the essentially similar RC-135W variant. These are the workhorses of the Sigint fleet and are distinguished by having extended “thimble” noses and large plate aerials under the center-section. External differences between the two variants are restricted to a lengthened cheek fairing on the W-model, which also lacks auxiliary air intakes on its engine pods.
Both aircraft are equipped with an extensive array of sophisticated intelligence gathering equipment enabling military specialists to monitor the electronic activity of adversaries. Also known as “RJ”, the aircraft are sometimes called “hogs” due to the extended “hog nose” and “hog cheeks”. “Rivet Joint” is an air refuelable theater asset with a nationally tasked priority. It collects, analyzes, reports, and exploits enemy BM/C4I. During most contingencies, it deploys to the theater of operations with the airborne elements of TACS (AWACS, ABCCC, Joint STARS, etc.) and is connected to the aircraft via datalinks and voice as required. The aircraft has secure UHF, VHF, HF, and SATCOM communications. Refined intelligence data can be transferred from “Rivet Joint” to AWACS through the Tactical Digital Information Link (TADIL/A) or into intelligence channels via satellite and the Tactical Information Broadcast Service (TIBS), which is a nearly real-time theater information broadcast.
RC-135s have been widely used in the 1990’s during Desert Storm, the occupation of Haiti, and more recently over Bosnia. Using automated and manual equipment, electronic and intelligence specialists can precisely locate, record and analyze much of what is being done in the electromagnetic spectrum. The fleet of 14 “Rivet Joint” aircraft increased to 15 in late-1999 with the addition of a converted C-135B.
RC-135S “Cobra Ball”
An altogether more specialized role is undertaken by three RC-135S aircraft which normally operate from Shemya Island, Alaska. In addition to “thimble” noses, electronic receivers mounted in cheek fairings and a teardrop-shaped fairing on the aft fuselage, these also have large circular windows in the fuselage for the photography of foreign ballistic-missile tests at long range. The intelligence equipment includes multiple infrared telescopes and is known as the Real Time Optical System (RTOS). These aircraft allow the U.S. to monitor every reentry vehicle flown from Russian test ranges, to determine the capabilities of each Russian missile, new or old.
Telemetry Intelligence (Telint) is the role of the “Cobra Ball”. With the decrease in foreign ICBM tests following the end of the Cold War, the RC-135Ss may adopt a theatre role spotting battlefield missiles. This is in response to the difficulties caused by the Iraqi “Scud” missiles during the Gulf War.
The RC-135 fleet has consistently proved of great value, both as a strategic reconnaissance tool during peacetime and as a more tactical asset during times of tension.