This series of satellites were reportedly low orbit ELINT/SIGINT satellites, possibly a continuation of the P-11 "Subsatellite Ferret" program.
The satellite were orbited by Titan-2(23)G launch vehicles into a very low orbit, which was then raised by their own propulsion system to a operational height of 790 km.
Reportedly these satellites carried Farrah SIGINT payloads similar to the two Farrah subsatellites. The serial numbers of the P-11 satellite busses hint, that these were a modified and possibly enlarged version. Reportedly these satellites were disk-shaped to allow a transition of P-11 type payloads to be launched on the Shuttle. Due to the Shuttle requirement, the satellites were launched inactive only to be activated by a timer shortly after deployment. The satellites were transferred to Titan-2(23)G launch vehicles after Shuttle launches to polar orbits were cancelled after the Challenger accident.
The first satellite, Farrah 3 or USA 32, was launched into a near-circular 85°, 790 km orbit on 5 September 1988. Amateur observations hint that it was still operational in 2021.
The second satellite, Farrah 4 or USA 45 was launched on 6 September 1989, but apparently the propulsion system of the satellite failed, leading to a reentry on 13 September 1989. If the satellite had raised its orbit, the orbital plane would have been 90° to the east of that for USA 32. The propulsion system failure was reportedly caused by an activation timer, which was not triggered after deployment.
A third satellite, Farrah 5 or USA 81 followed on 25 April 1992. The orbital plane of this satellite is 90° to the west of that for USA 32. Amateur observations hint that it was still operational in 2021.
In 1995 it was reported, that the program had ended with functiones consolidated into the Navy's Intruder (NOSS) series. As three of the six Titan-2(23)G launch vehicles, originally converted for classified use, were made available for other programs, it is likely, that this ELINT satellite program originally contained six satellites.
|Type / Application:||ELINT, SIGINT|
|Operator:||US Air Force (USAF)|
|Configuration:||mod. P-11 bus / C-BUS|
|Power:||Solar arrays, batteries|
|Orbit:||784 km × 791 km, 84.99° (#32); 185 × 300 km, 85.00° (#45); 791 km × 797 km, 85.02° (#81);|
|P-11 5101||-||cancelled||Va SLC-4W||Titan-2(23)G|
|P-11 5102||-||cancelled||Va SLC-4W||Titan-2(23)G|
|P-11 5103 (USA 32)||1988-078A||05.09.1988||Va SLC-4W||Titan-2(23)G|
|P-11 5104 (USA 45)||1989-072A||06.09.1989||Va SLC-4W||P||Titan-2(23)G|
|P-11 5105 (USA 81)||1992-023A||25.04.1992||Va SLC-4W||Titan-2(23)G|
|P-11 5106||-||cancelled||Va SLC-4W||Titan-2(23)G|