The ELINT/SIGINT satellites known for decades only as "Heavy Ferrets" are now known to be a program originally associated with the Samos (Satellite and Missile Observation System) project. This first series of Heavy Ferrets was called Program 102, later renamed Program 698BK and Program 770. These satellites were designed to detect, map and investigate SAM and ABM radars.
They were an improved version of the preceding Agena-B based P-102 / P-698BK series. They were based on the improved Agena-D stage. Additionally, this series also features three deployable solar arrays to prolong the operational life.
The digital ELINT payload was an all-solid state system, which had many advantages over the vacuum tubes and mechanical scanners of the Group 0 payload. In addition to extended frequency coverage, this system was much lighter, more reliable, and used considerably less power. The frequency range from 59 to 12,500 MHz was covered in three configurations (Groups 1 through 3).
To provide the wide-bandwidth TI needed to understand the operation of new Soviet ABM and ground-to-air radars, operation of the Group 1-A analog payloads was necessarily more complex. Recording of radar intercepts was accomplished by the AMIE recorder developed for this task by RCA in Camden, New Jersey. To obtain the 4 MHz bandwidth of the early models, a helical scan machine was developed using four recording heads scanning sequentially in exactly the way present-day video cassette recorders CVCRs) operate. To obtain maximum utilization of the wideband recording capability of the AMIE recorder, it was necessary to stop the frequency scan of the receivers and dwell on the frequency of interest while making the recording. The receiver had to either recognize a signal of interest (at least, the presence of a signal) or be pretuned to suspected frequencies of interest.
Several missions carried the Bird Dog interferometer-type ELINT auxiliary payload.
The first wideband analog mission, 7156, Vehicle 2316 or P-698BK Group 1-A 1 was launched on 27 February 1964, with a mission life of 12 days. The value of the data was degraded by erratic operation of the wideband AMIE helical-scan tape recorder, mostly caused by tape "gunking" of the recording heads, resulting in frequent loss of data from one or two of the recording heads, The down link data limited the analog data bandwidth to about 750 MHz and further degraded the data. It carried also the Bird Dog 2 auxiliary payload.
P-698BK Group 2-D 2, also known as Vehicle 2315 or Mission 7155, a Group 2 digital payload. was launched on 3 July 1964. It also carried the Bird Dog 1 auxiliary payload. It operated for 17 days.
The P-698BK Group 3-D 1 mission, Vehicle 2317 or Mission 7157, carrying a Group 3 digital payload, was launched on 3 November 1964 and operated for four days. It also carried the auxiliary payload Bird Dog 3. This version used an inflatable antenna system, which proved to be incapable of withstanding orbital conditions and collapsed, completely ending thoughts of low frequency Bird Dogs.
P-770 Group 1-A 2, the first Project 770 mission, vehicle 2702, mission 7158, launched on 16 July 1965, was the second wideband analog payload, which was launched on 27 February 1964). It was a Group 3 configuration covering 640 MHz to 8.28 GHz. It operated for 51 days and marked the first effective use of solar arrays on a SIGINT vehicle (vehicles starting with 2316 had solar arrays, but battery problems prevented effective use or very long life). It also carried the auxiliary payload Bird Dog 4.
P-770 Group 3-D 2, the last F-2 type payload was Mission 7160, carried on vehicle 2703, was a Group 3-D payload launched on 9 February 1966. It also carried a 100 kHz bandwidth Leach magnetic tape recorder of the same type used on mission 7157 for analog-signal detection. Altogether, 736 readouts of digital and 429 readouts of analog data were collected during the seven-month lifetime of the payload. Several thousand updates to the EOB data were furnished to DLA and SAC, but the analog data suffered from the same bandwidth restrictions that plagued the mission 7157 data and little technical intelligence (TI) was produced. It also carried the auxiliary payload Setter 1, which was a follow on to Bird Dog.
This series was followed by the P-770 Multigroup version of the Heavy Ferret satellites.
|Type / Application:||ELINT, SIGINT|
|Equipment:||Group 1-A, Group 2-D or Group 3-D ELINT payload; Bird Dog ELINT payload (#1-4); Setter ELINT payload (#5)|
|Power:||3 deployable solar arrays, batteries|
|Orbit:||493 km × 508 km, 82.07° (#1), 494 km × 530 km, 82.08° (#2), 507 km × 526 km, 82.04° (#3), 469 km × 512 km, 70.19° (#4), 499 km × 504 km, 82.08° (#5)|
|P-698BK Group 1-A 1 & Bird Dog 2 (P-698BK 7156, OPS 3722)||1964-011A||28.02.1964||Va 75-3-5||Thor-SLV2A Agena-D|
|P-698BK Group 2-D 2 & Bird Dog 1 (P-698BK 7155, OPS 3395)||1964-035A||02.07.1964||Va 75-3-5||Thor-SLV2A Agena-D|
|P-698BK Group 3-D 1 & Bird Dog 3 (P-698BK 7157, OPS 3062)||1964-072A||04.11.1964||Va 75-3-5||Thor-SLV2A Agena-D|
|P-770 Group 1-A 2 & Bird Dog 4 (P-770 7158, OPS 8411)||1965-055A||17.07.1965||Va 75-1-2||Thor-SLV2A Agena-D|
|P-770 Group 3-D 2 & Setter 1 (P-770 7160, OPS 1439)||1966-009A||09.02.1966||Va 75-1-2||Thor-SLV2A Agena-D|