The Arroyo satellite was part of a series of so called Program 11 or P-11 "Subsatellite Ferrets", low orbit ELINT/SIGINT satellites to pinpoint and characterize different Radar emitters in the Soviet Union and Warsaw pact states.
Arroyo was a communications intelligence (COMINT) payload scanning the 1200–2250 MHz range. Although the payload was on orbit only one month, it collected a large quantity of information.
The satellites were based on Lockheed's P-11 bus, which was designed to fit on the aft rack of the Agena-D upper stage. The bus contained each one or two focused payload black boxes and different antenna configurations according to payload, as well as deployable solar arrays. The satellite featured two solid rocket motors, which allowed them to rise and circularize their orbit after deployment from the host satellite. Both spin or gravity gradient stabilization was possible.
This subsatellite was deployed from the propulsion rack of an Agena-D stage of a KH-4B Corona satellite. It used two solid-fuel kick-motors to maneuver itself into its operational orbit after deployment.
Arroyo was launched on 16 September 1971 and performed exceedingly well until mid-October 1971 at which time the spacecraft suffered a power failure, thus ending the mission.
|Type / Application:||SIGINT, COMINT|
|Operator:||US Air Force (USAF)|
|Contractors:||Lockheed (bus); Airborne Instrument Lab (payload)|
|Power:||Solar cells, batteries|
|Orbit:||487 km × 504 km, 75.07°|
|Arroyo (P-11 4427, Mission 7337, OPS 7681)||1971-076B||10.09.1971||Va SLC-3W||Thorad-SLV2H Agena-D||with KH-4B 15|