Boeing RC-135: Rivet Joint, Cobra Ball and Combat Sent
The Air Force RC-135 family — Rivet Joint, Cobra Ball and Combat Sent — flies SIGINT, ELINT and missile tracking from Offutt for U.S. and allied ISR.
OFFUTT AIR FORCE BASE, Neb. — Nov. 5, 2026 — The Boeing RC-135 family remains the U.S. Air Force’s primary manned platform for airborne signals intelligence, electronic intelligence and ballistic-missile observation. Three variants — the RC-135V/W Rivet Joint, the RC-135S Cobra Ball and the RC-135U Combat Sent — operate from Offutt under the 55th Wing and deploy worldwide for theater and national customers.
According to the U.S. Air Force Rivet Joint fact sheet, the RC-135V/W supports theater and national-level consumers with near-real-time on-scene intelligence collection, analysis and dissemination. The aircraft is an extensively modified C-135 whose sensor suite lets the mission crew detect, identify and geolocate signals across the electromagnetic spectrum, then push that information through a large communications suite. The Offutt Air Force Base mirror of the same fact sheet repeats those points and the inventory figures below.
Three missions, one airframe family
Rivet Joint is the bulk of the fleet. The Air Force lists 17 active RC-135V/W aircraft, with a mission crew of 21 to 27 people depending on the sortie — a minimum of three electronic warfare officers, 14 intelligence operators and four in-flight maintenance technicians — plus an augmented flight crew of five. The interior seats more than 30 people. Initial operating capability dates to January 1964. Unrefueled range is listed at 3,900 miles, ceiling at 50,000 feet and maximum takeoff weight at 297,000 pounds, on four CFM International F108-CF-201 engines.
Cobra Ball does a different job. The Air Force Cobra Ball fact sheet describes the RC-135S as a rapidly deployable aircraft that flies Joint Chiefs of Staff-directed missions to collect optical and electronic data on ballistic targets — information used for arms-treaty compliance verification and for U.S. strategic and theater missile-defense concepts. Three aircraft are in the inventory, all at Offutt, crewed by the 45th Reconnaissance Squadron and the 97th Intelligence Squadron. Cobra Ball II entered service in March 1972; the fleet moved from Shemya, Alaska, to Offutt in 1994.
Combat Sent is the smallest slice. Offutt’s Combat Sent fact sheet says the two RC-135U aircraft provide strategic electronic reconnaissance to the president, the secretary of defense, Defense Department leaders and theater commanders by locating and identifying foreign military land, naval and airborne radar signals. Collected data is also stored for deeper analysis. The type is identified by chin and wingtip antenna arrays, large cheek fairings and an extended tail; aerial refueling gives it effectively unlimited range. Crews include a minimum of 10 electronic warfare officers — “Ravens” — plus six or more specialists, drawn from the same 45th and 97th squadrons.
Who flies them, and from where
Offutt’s Welcome page identifies the 55th Wing as the host unit and the largest wing in Air Combat Command. Beside Rivet Joint, Cobra Ball and Combat Sent, the base hosts the WC-135 Constant Phoenix atmospheric sampler, the E-4B National Airborne Operations Center and the Navy’s E-6B Mercury. All RC-135s are assigned to Air Combat Command and use forward deployment locations worldwide, the Rivet Joint fact sheet states.
That forward footprint is expanding in the north Pacific. In a 25 July 2023 release, 55th Wing Public Affairs reported that the 55th Operations Group established Detachment 1 at Joint Base Elmendorf-Richardson, Alaska, as a strategic launch and recovery point for Rivet Joint operations and exercises in the Indo-Pacific. Col. Derek Rachel, then 55th Operations Group commander, said the detachment would give the wing more flexibility against rising intelligence requirements; the site is also available for Cobra Ball, Combat Sent and the WC-135R. The permanent presence was described as fewer than 10 active-duty airmen plus a few contractors.
Allied Rivet Joint: the RAF Airseeker fleet
The United Kingdom flies the same basic Rivet Joint type. The Royal Air Force aircraft page for the RC-135W says three aircraft entered operational service from 2014 under Project Airseeker, are operated by No. 51 Squadron at RAF Waddington, and are planned to counter electromagnetic threats through 2035, remaining interoperable with U.S. systems. Ground specialists in No. 54 Signals Unit process and exploit the collected data.
On 26 October 2021 the RAF announced that the Rivet Joint Cooperative Programme with the United States had been extended to the UK out-of-service date in 2035, with the Ministry of Defence committing £970 million over 14 years for maintenance, spares, engineering support, technical data and capability updates. Defence Minister Jeremy Quin called the programme an example of UK–US cooperation on surveillance capability.
Key specs
| Variant | Role (official) | Inventory | Primary source |
|---|---|---|---|
| RC-135V/W Rivet Joint | Near-real-time SIGINT collection, analysis, dissemination | 17 active (AF fact sheet) | Air Force / Offutt RJ fact sheets |
| RC-135S Cobra Ball | Optical + electronic data on ballistic targets | 3 active | Air Force Cobra Ball fact sheet |
| RC-135U Combat Sent | Strategic ELINT on foreign radar systems | 2 active | Offutt Combat Sent fact sheet |
| RAF RC-135W Airseeker | Electronic / signals intelligence; US-interoperable | 3 aircraft (Project Airseeker) | RAF aircraft page |
A Congressional Research Service report (R44108, 15 July 2015), archived at EveryCRSReport, counted the same U.S. inventories — 17 Rivet Joint, 2 Combat Sent and 3 Cobra Ball — inside the broader Boeing 707-based C2ISR force, confirming the Air Force fact-sheet totals for that period.
Why it matters
Analysis, based on the sources cited in this article:
The public record describes a division of labor, not a single “spy plane.” Rivet Joint feeds day-to-day theater and national consumers with spectrum-wide collection; Combat Sent specializes in characterizing foreign radars for electronic warfare planning; Cobra Ball watches ballistic targets for treaty and missile-defense work. Keeping all three under one wing at Offutt concentrates scarce aircrew, maintainers and mission-system expertise.
The 2023 Alaska detachment is the clearest recent official signal that Indo-Pacific tasking, not only the long Southwest Asia presence noted on the Rivet Joint fact sheet, now shapes basing. Pair that with the RAF’s three Airseeker jets on a cooperative support line to 2035, and the RC-135 enterprise looks less like a Cold War leftover and more like a shared U.S.–UK sensor fleet that combatant commands still book for near-real-time collection.
What the open sources do not disclose — and what this article does not claim — are current sortie rates, specific collection targets, or classified sensor performance. Inventory and mission statements above are those the Air Force, Offutt and the RAF publish.
What to watch: further permanent or rotational RC-135 presence announcements in the Indo-Pacific; any Air Force budget justification updates to Rivet Joint baseline modifications; and whether the UK publishes follow-on sustainment decisions as 2035 approaches.
Sources
- U.S. Air Force, RC-135V/W Rivet Joint fact sheet; mirrored at Offutt AFB.
- U.S. Air Force, RC-135S Cobra Ball fact sheet.
- Offutt Air Force Base, RC-135U Combat Sent fact sheet.
- 55th Wing Public Affairs, 55th Operations Group establishes new detachment in Alaska, 25 July 2023.
- Royal Air Force, Rivet Joint RC-135W (Airseeker) aircraft page; UK and US extend Rivet Joint support until 2035, 26 October 2021.
- Congressional Research Service, U.S. Command and Control and Intelligence, Surveillance, and Reconnaissance Aircraft (R44108), 15 July 2015 (EveryCRSReport archive).
Additional sources
- Offutt Air Force Base, Welcome / base overview (55th Wing aircraft list).
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