Ursala 1, 2, 3, 4 (P-11 4425, 4426, 4430, 4431)

Ursala [NSA]

The Ursala satellites (also sometimes spelled Ursula) were 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.

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 or later on a rack on the KH-9 Hexagon reconnaissance satellite. 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.

Ursala was a ELINT mission targeted at EOB/Ops. They provide precision frequency measurements on pulsed emitters.

These subsatellites were deployed directly from KH-9 Hexagon reconnaissance satellites. They used two solid-fuel kick-motors to maneuver themselves into their operational orbits after deployment.

Ursala 1 suffered from a payload overheating resulting in a six day loss of pulse radar data.

At least four Ursala satellites have been build, but the identification of the fourth is tenative.