Which ISTAR aircraft provides signals intelligence and is designated RC135W Rivet Joint?

• A. E-3D Sentry
• B. Rivet Joint RC135W
• C. Sentinel R1
• D. Shadow R1

Answer: (B)

Signals intelligence is about intercepting and analyzing electronic emissions to gather information about potential adversaries. The RC135W Rivet Joint is the RAF’s dedicated SIGINT aircraft, a variant of the US RC-135 designed specifically to collect, geolocate, and interpret signals from multiple sources. This makes it the clear fit for the role described: an ISTAR asset whose primary purpose is signals intelligence, officially designated as RC135W Rivet Joint.

In contrast, the E-3D Sentry is built for airborne early warning and battle management using radar, not primarily SIGINT. The Sentinel R1 and Shadow R1 are ISR aircraft with broader surveillance roles, but they are not designated RC135W Rivet Joint and are not the standard SIGINT platform referred to by that designation.