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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.

Nation: USA
Type / Application: ELINT, SIGINT
Operator: US Air Force (USAF)
Contractors: Lockheed (bus); Motorola (payload)
Equipment: ?
Configuration: P-11 bus
Propulsion: Kick motor
Power: Solar cells, batteries
Mass: 202 kg (#1)
Orbit: 493 km × 501 km, 96.14° (#1); 485 km × 503 km, 96.32° (#2); 598 km × 602 km, 96.34° (#3); 621 km × 628 km, 95.80° (#4)
Satellite COSPAR Date LS Launch Vehicle Remarks
Ursala 1 (P-11 4425, Mission 7338, OPS 7803) 1972-052C 07.07.1972 Va SLC-4E Titan-3D with KH-9 3
Ursala 2 (P-11 4426, Mission 7342, OPS 7705) 1973-088C 10.11.1973 Va SLC-4E Titan-3D with KH-9 7, P-801 5
Ursala 3 (P-11 4430, Mission 7343, OPS 5366) 1976-065C 08.07.1976 Va SLC-4E Titan-3D with KH-9 12, S3 3
Ursala 4 (P-11 4431, Mission 7345?, OPS 6675) ? 1979-025B 16.03.1979 Va SLC-4E Titan-3D with KH-9 15

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