OVERVIEW: The Ariel Mk 1 Towed Radar Decoy (TRD) is an expendable airborne electronic countermeasure designed to protect large and fast-jet aircraft from radar-guided missiles by deceiving their seekers at a distance. It trails behind the host aircraft, presenting a convincing false target signature.

DETAILS: The Ariel Mk 1, developed by GEC-Marconi (now BAE Systems), is a towed decoy optimized to thwart monopulse radar seekers across H‑ to J‑bands through angular deception. It can be deployed from maritime patrol aircraft or tactical platforms at speeds from 352 km/h to Mach 1.2, towing ~200 m behind the aircraft, with about 2 minutes of operational lifespan . The Mk 1 integrates via a towline containing fiber‑optic, electrical conductors, and Kevlar; its flight body houses photodetectors, TWT amplifiers, and antennas, acting as a repeater/deception jammer under direction from the aircraft’s onboard techniques generator. It can be recovered in some missions, though it's considered expendable due to vulnerability during deployment.

“Ariel” draws from Shakespeare’s airy spirit; “AN” and “SLQ” designations align with airborne countermeasure systems. The Mk 1 is the initial production variant, featuring standard repeater/deception capability without later enhancements seen in Mk 2 or Mk 3.

FUNCTION: Deployed on a fiber‑optic towline, the Ariel Mk 1 receives threat waveforms via the aircraft’s emitter, then retransmits modulated jamming signals to seduce or disrupt radar or missile seekers, luring threats away from the aircraft.

NOTE:
IOC: circa 2000 (fast‑jet trials); exact IOC unknown
Operators: United Kingdom
Platforms: Tornado F.3; Nimrod RMP; tested on Typhoon TRD

SOURCE:
GEC‑Marconi Defence Systems (BAE Systems): “Towed Decoys Come Out of the Black,” Free Online Library; Jane’s Electronic Countermeasures Reports; Naval & Aviation EW Integration Technical Papers.