RC-135 COBRA BALL
U.S. RC-135S COBRA BALL aircraft are large aircraft, modified from transport aircraft, flown by United States Air Force crews of the 45th Reconnaissance Squadron, which are intended for collecting measurement and signature intelligence on foreign missile tests. In an operational context, potentially could be used for warning and tracking of theater-level ballistic missile launches. They are based at Offutt Air Force Base in Nebraska, but deploy worldwide.
With recent architectural changes, there is an increased commonality of parts with the RC-135V/W aircraft, which have a more signals intelligence with some MASINT capability. This will allow a RIVET JOINT aircraft to be reconfigured as a COBRA BALL, and vice versa. In addition, the functions of the RIVET JOINT, COBRA BALL, and RC-135 COMBAT SENT could be complementary during actual fighting, and these three intelligence, surveillance and reconnaissance (ISR) aircraft further complement the E-3 Sentry airborne warning and control system (AWACS) and the E-8 Joint STARS ground surveillance radar aicraft.
COBRA BALL's primary mission had been created to track Soviet mission developments, but, with the change in geopolitics, the was primarily used as a traditional mission in the past against Russia, but now the United States has no named enemy. This platform is evolving to meet new roles and missions, and now carries linguists proficient in many languages. This is part of the joint Air Force/Navy When the PONY EXPRESS operations, with a communications intelligence capability for backing up the RC-135 RIVET JOINT. 
Am operational, rather than national intelligence collection, mission could be detecting and tracking theater ballistic missiles.  COBRA BALL could be cued to a target by a Defense Support Program (DSP) satellite. DSP satellites have worldwide coverage, and detect intense heat sources such as rocket engine ignition.
Along with sea-based and possibly ground-based sensors, the original COBRA mission can be adapted to observing long-range missiles, but is also appropriate for theater-level weapons, which may be addressed in regional arms limitation agreements, such as the Missile Technology Control Regime (MCTR). Where COBRA JUDY is built into a ship, this dual frequency (S- and X-band) radar is transportable, capable of operating on ships or on land, and optimized for monitoring medium range ballistic missiles and antimissile systems. It is air-transportable to deal with sudden monitoring contingencies.
COBRA BALL operates as part of a MASINT system, cooperating with COBRA DANE ground and COBRA JUDY sea-based radar. It has electro-optical MASINT sensors that are "...two linked electro-optical sensors -- the Real Time Optics System (RTOS) and the Large Aperture Tracker System (LATS). RTOS consists of an array of staring sensors encompassing a wide field of regard for target acquisition. LATS serves as an adjunct tracker. Due to its large aperture, it has significantly greater sensitivity and resolving power than the RTOS, but is otherwise similar. COBRA BALL cues the COBRA DANE ground radar and the COBRA JUDY ship-based radar. See Radar MASINT.
The original COBRA DANE ground radar, however, is not mobile, so the COBRA JUDY can work with COBRA BALL in much of the world. Work on a transportable ground system appears to have been halted.
COBRA BALL vs. RIVET JOINT
There is a broader program to standardize the architecture of the various RC-135 aircraft, so that there will be greater commonality of parts, and some ability to switch missions:
The infrared countermeasures was not limited to flares, but directed energy from the AN/ALQ-157 system. The aircraft has an AN/ALE-47 Countermeasures Dispenser System [CMDS], is a "smart" dispenser that connects directly to infrared and radar warning receivers, release expendable and towed/retrivable decoys, as well as helping the pilot with situational awareness of the threat.
Some of the specifications for the aircraft proper, as opposed to its crew or deployment, are assumed to be that of the interchangeable RC-135V/W RIVET JOINT.
- Primary Function: Reconnaissance
- Contractor: L-3 Communications
- Power Plant: Four CFM International F108-CF-201 high bypass turbofan engines
- Thrust: 21,600 pounds each engine
- Wingspan: 131 feet (39.9 meters)
- Length: 135 feet (41.1 meters)
- Height: 42 feet (12.8 meters)
- Weight: 173,000 pounds (78,743 kilograms)
- Maximum Takeoff Weight: 297,000 pounds (133,633 kilograms)
- Fuel Capacity: 130,000 pounds (58,967 kilograms)
- Speed: 500+ miles per hour (Mach.66)
- Range: 3,900 miles (6,500 kilometers)
- Ceiling: 50,000 feet (15,240 meters)
- Mission flight crew: 21-27, depending on mission requirements, minimum consisting of 3 Electronic Warfare Officers (Ravens), 14 Intelligence Operators and 4 Airborne Systems Engineers. Current crews may be smaller, has five slots for an airborne mission supervisor, manual Morse operator, cryptolinguist, air communications operator and one maintenance technician.
- Date Deployed: Initial RC-135 conversions from 1964-1968; V/W configurations, 1981
- Inventory: Active force, 17; Reserve, 0; Guard, 0