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E"Cd.:oe£/ FROM A~!~OMJ..r;( 

OE(,R'A£/.I<otG 000 i) ... SZC': '0 

r::OES .. O~ A tlPt '\" TOF SECRET 

NATIONAL RECONNAISSANCE OFFICE 

SATELLITE OPERATIONS CENTER 

DESCRIPTION OF 

SI INT ISSIONS 

7167 /7236 /7240 

3 , 

WARNING 

This i10cuntn: ::1"'1),11\ ,nio,o:atlon affeC!lng the natIOnal security of the Untted 

States ,",th,n 'tl, 'TJPa,,"',; of the espHJnap-e laws U S Code Title 18, Sections 793 

and }94 Ttlt : <3 v, [lft]hrods II) transrflisslon or the reve!atlOn of Its contents tn any 

manner 'I; dr; '.l;",HJttH,'t~lec pef:,or1 3S wt?ll as Its use HI any matter preludKlal to the 

safery c,' "',,",! fl!~ UnIted Stoles or for the benelll o! any foreign government 

~o tnt ~i.'r'·l',1i·f'.~ ;' ~~'il: Uf1ltl:O ~!a\es It IS ~o be seen only by personnel espeCIally 

!(vk;.! U:I;'ited ,.~:11.1 ·h,tt~ :f(Jed kl H?,.elV~ Information :n the desIgnated control channels 

tf~ ,)f"t:v:~t, ;';)1)'): ri~ '~!a !je(j !i' dt()lfldflce with regulations pertaining 10 the deslg 

f1a,tfC :ijntfui:.. 

Printed by the 

NATIONAL PHOTOGRAPHIC INTERPRETATION CENTER 

\ 

prepared for sigint overhead reconnaissance subcommittee 

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handle Yia, ... AI... ..... ·ICE_MD ..... con,trol oDI", "' 

CONTROL NO. TCS-37562-71 (,R(ivP 

{l(.vOfO n:.olol _.'JTOU",',,_ TOP SECRET COPY NO. -""" OF 76 

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HANOI E 

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Mission Description 7167/7236/7240 

1. INTRODUCTION 

1.1 General. 

Missions 7167, 7236, and 7240 are SIGINT payloads which will be 

carried aboard a 3-axiG stabilized satellite system. These payloads collect 

electronic signals, store intercepted data ,'\ digital and analog form. and 

later transmit this data to various satellite tracking stalions throughout the 

world. This mission description will discuss the technical and operational 

considerations applicable to each payload. 

1. 2 Missions 7167 and /236. 

TIlese missions are identical to Missions 7166 and 7235 except that 

Mission 7236 has 16 recognizers instead of the eight which are carried bj 

Mission 7235. With this one exception, the mission des.;ription for 7166 and 

7235 (rCS-37573-70, 12 June 1970) is valid for Missions 7167 and 7236. 

1. 3 Mission 7240. 

Mission 7240 is a directed-search SIGINT payload which was designed 

to collect signals in the frequency range of 2.0 to 12.0 GHz. The primary 

purpose of Mission 7240 is to maximize the probability of intercept of signals 

emanating from the I radar, but it can be used as a 

di"c"ected-search system agall1st any other emitter in the frequency range of 

L to 12 GHz which has kLlOwn geographical locations as weil as a general 

search system. 

The unique feature of this payload is the antenna tracking or steering 

system which keeps the main beam of the intercept antenna boresighted on the 

target emitter/area c.z interest during the satellite pass over the target. In 

this manner, signals emanating from the target are enhanced because the 

intercept system always views the target emitter/area with maximum sensitivity 

and cO]Tespondingly reduces the amount of unwanted signals being received from 

outside the target area. 

50X1 

TOP SECRET (OmOLNO TCS-37562-71 

(XC:uDfO fHOM A,}10Mi<;I( IlF(,HADING 

DOt) OIREC11~t '>~O(; 1\' 001-', ~.Ol Ar>i->l\ 

cOPY_--1-nl'_~ COPIES 

I':'Gf_L_ or ___ If---_- PACfS 
HA',Cl.( '"II 

TOP SESRET 

Mission 7240 was designed to share certain common components of 

Mission 7167/7236 such as the Core Storage Units (CSU), Data Storage Units 

(DSU) and the command programmer. 111is mission description will discuss 

the following technical and operational aspects of the payload required for 

I1l is sion planning: 

<l. J<.eceiver Subsystem 

ll, Antenna S LIbsy ste ill 

c. Payload Interface EqUipment 

d. Summary of System Characteristics 

2. H.ECEIVEI\ SUBSYSTEM 

2.1 BF Section. 

Tl1e receiver subsystem is designed to intercept both pulse and C W 

sig-nals in tl~'3 frequency range of 2 to 12 GHz. The receiver is (jjvidecl into 

10 frequer;cy bands which are 1000 MHz wide, The bands are divided 2 to 

3 GHz. 3 to 4 GHz through 11 to 12 GHz. Each band is clownconverted to 1 to 

2 GHz where it is furti1er divided into four 25(}-J'y1Hz segments. Each of the 

four segments are again c1ownconverted to 125 to 375 I\l'E-Iz where separate 

narrowband (4 MUz) aml widebancl (250 l:'v1Hz) receivers are used to process 

intercepted signals. 

The narrowband receiver is a synti1esizer-tuned, t;'J~x;rheteroclyne, 

VHF rc"'Ceiver whi.ch has a 4-MHz bandwidth and tunes the dO\v'nconvertec1 

frequency range of 125 to 375 rv11iz in 2-1v11-13 steps. 111C narrowband receiver 

can be step-tuned in anyone of three modes, They are: (1) scan 2 to 12 

GHz [Torn the lowest frequency to ti1e highest frequency, (2) scan 4 to 12 

8Hz from the lowcst frequency to tJ1C highest frequency, and (3) scan up to five 

sel(xtccl frequency seg111ents as defined by sectors of the frequency search 

memory. Each sector is defined by an upper and lower frequency iimit, and 

each frequency limit can be any 2-MHz step in the 2 to 12 GHz frequency 

~'ange (in any order). Aclditionally, the receiver ca.') be fixed-tuned to any 

2-MHz step for the entire payload operating time. 'Ole narrowband receiver 

has two selectable elwell periods after stepping. "Ole normal dwell period for 

each frequency step is 3.125 milliseconds which extends to 128.125 milliseconds 

for sigl1als which exceed a fixed threshold and a rc: received in t.he main beam of 

the intercept antenna. A fixed 125-mHlisecond dwell period for each frequency 

TCS-.37'S62-71 

TALENT -KEYHOLE TOP SECRET ,.: .. 'q'J, •• c _______ .. _____ _ 

CONTROl <'Y'} 1 r p.,< 

Approved for Release: 2017/08/16 COS099 
TOP SECRET 

step can also be selected. The narrowband receiver is '--<,"!.J<I,JJA«~ fjf 

both pulse and CW signals. 

The wideband receiver is a fixed-tuned receiver 'Hhich takes till;; 

TAlEHT~KEYHOlE 

2S0-i'vlHz RF segment (125 to 375 MHz) and passes it ae dHeCUjr 

a,nd a low pass filter to output a 2S0-i'>.1Hz RF j400-KHz r:an,bii,:th cletecte,; 

(stretched) video signal. The wideband channel is 'Jsed to ict(:rcept p'-1be 

frequency jumping emitters. 

Tuning of the wideband receiver is accomplished autrjr;,aricai1::. T;-;c 

wideband receiver is always tuned to the 25(}-).1;1z in ';;hidt th<: ,_,lr:rrFlIband receiver is being step tuned. For example, if ttl':; fi«l:-r ffNbard recc~i-/er :'s 

being tuned at 8,292 MHz (the second 2S0-MHz seg.ncnt 'Jf the: ,j. (; to <). (J GHz 

range), the wideband receiver will be turK'rl bervleen 8.250 t(l 8.5(;0 GHz 

(inclusive). 

Figure 2.1 is a simplified block diagram wh.ich i1Ltst:rat(~~ hr;-.j; 

signals are pnx::essed by the narrowband and widei),LHJ recc:ive;-s. 

2.2 Signal Outputs. 

Analog Data. 

TIle narrowband receiver outputs 4-.\1Hz rreGetec~ed '."ider; 2rJ: t!-,e 

wideband receiver outputs 250-\frIz RF j400-KHz \'j~e() data whidl r with 

a 6-MHz reference tone is recorded in the Data Unit 

Two 48-bit marker words cO!1taining system time, H.'ceh-er 

recognj;;-:er, vehicle attitude, :'i.1issiC!11 7240 i1.nt(;nna attit'lCe, aLd v),cr:;a~J~ stat'J" 

are recorded every 125 milliseconds on the digital crack 'A t11(: i),lta f.; rj r:, 

Analog data outputs from the narrowband and v;ideLaml receh-(~n: are cr,;:,trol1e(' 

by selecting anyone of three sidelcJbe inhibit qualification cri':eria. 

2.2.2 Digital Data. 

The narrowband receiyc:r has a ;: 

encoder which will output digital data to the CSU 'NhLf.:c:'-/er- it 

which exceed a selectable threshold (normally set at. I') db 

the sidelobe inhibit criteria. There are tVJO selectable r;;(}ce:s 

measurement/dib-rital e:!Cooer unit operation. The first lTIG;:;{: 

will output the digitized parameters !Jf the first four v:hich n,(:et the ttr,a:;;':-

old and siddobe inhilJH criteria on a E,riven frequency during the sp\:Cuied \}w~ll 

period, and likewise, the second mode (16-pulse ITte,Je) wili uutpUt the digitizE;(' 

parameters of the first 16 pulses 'Nhich meet the criteria. Table 2.1 

lists the parameters which are measured, 

receiver. 

TCS-37562-71 

TOP SEGRET 
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Figl1re 2.1 -~---~ -- ---~----- -- --- - --~--

Simplified Block Diagram of Mission 

72·iQ RF dnd Video Processing Circuitry 

NOTE: Onmi Channci and Side Lobe 

Inhibit Circuitry is !lot shown. 
KII"IOLE VIA 

HANOl E VI" 

TOP SESRET TALENT-KEYHOLE 

Table 2.1 

Parameter Measurement Range; Resolution 

Frequency -±"2 N1Hz 

PRI 30 to 131,071 msec; 1 microsecond 

PW 0.167 to 42.5 msec; 0.167 microsecond 

Pulse Amplitude 40 db dynamic range; 3 db 

3. ANTENNA SUBSYSTEM 

3. I Antennas. 

The Mission 7240 antenna system consists of two high gain intercept 

antennas and two low gain omnidirectional antennas mounted on a common 

platform 0 The platform is gimbaled for preprogrammed rotation in both pitch 

and roll. 

TIle intercept antenna covering 2 to 8 GHz (low band) is a 36-inch 

unfurlable dish which has a gain of 22 to 31 db and a beamwidth of 3.3 to 

CONTROL SYSTEM 

10 degrees--both gain and beamwidth are a function of frequency. The 

intercept antenna covering 8 to 12 GHz (high band) is a 20-inch solid dish which 

has a gain of 31 to 35 db and a beamwidth of 3.3 to 5 degrees. The footprint of 

the low band intercept antenna at nadir varies from a circle of 48 miles in 

diameter ;It 2 GHz to about 16 miles in diameter at 8 GHz. The footprint of the 

high band intercept antenna at nadir varies from 24 miles (diameter) at 8 GHz to 

about 16 miles (diameter) at 12 GHz. 

Two conical spiral antennas (one for 2 to 8 GHz, the other for 8 to 12 GHz) 

are used as sidelobe inhibit antennas. 

3.2 Antenna Tracking System. 

The unique feature of Mission 7240 is the antenna tracking or steering 

system. The two intercept antennas and the two sidelobe inhibit antennas are 

mounted on a common platform which is gimbaled to rotate in both pitch and roll 

(in-track and cross-track, respectively). 

The purpose of the antenna tracking system is to keep the intercept 

antenna systems boresighted with the target emitter of interest during the entire 

CONTROL NO TCS - 37562 - 71 TOP SESRET COpy I OF Z &. COPIES 

CoNTROL SVS1'(M EXCLUDED FROM AUTOMATIC ReGRADING PAGE 5 OF_8 PII,('!;S 

DOD DIRECTlvl; 5100 10 Dc~S NOT APPLY 
f.lA)o;Dlf VIA 

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pass of the satellite over the target area. This technique maximizes the I 

probability of intercept of the target emitter by alwaYJ keeping the main beam 

Cligh gain portion) of the intercept antennas pointing at the target emitter, and I 

it also helps to reduce interference (extraneous signals) from nontarget emitters. 

Preprogrammed antenna steering commands a~e stored in the command I 

programmer utilized by Missions 7167/7236. The antennas can be steered in-track 

(Pitch) from nadir (0 degrees) to the horizon (68 degrees), and the antennas can be 

steered cross-track (roll) plus or minus 30 degrees from nadir. The platform 

drive system utilizes a four pole stepper motor for both pitch and roll and has a total I 

of seven different pitch rates available. 

4. PAYLOAD INTERFACE EQUIPMENT 

-1.1 General. 

]11e operation of Mission 7240 depends upon the utilization of certain 

components which are shared with Missions 7167 and 7236. These components 

are the Digital Command PrOb'Tammer (OCP), the Data Storage Units (DSU), and 

the Core Storage Units (CSU). 

4.2 Hanh>vare. 

4.2.1 Dil:,rital Command Programmer. 

The DCP is a mini-computer which controls tile operation of each 

of tile payloads. The DCP is loaded generally only once per clay, and it allows 

each of t1le payload configurations to be altered many times on any pass. 

4.2.2 Data Storage Unite 

The DSU is a 6-MIiz tape recorder which has approximately 40 

minutes of readin capacity. There are two recorders (one for redundancy) and 

eac:l can te operated in several different modes. Only one DSU may be operated 

at anyone time. The DSU can be exclUSively assigned to anyone/or two of tile 

paylOads, or it c[ln be shared by all three. In the latter mode, the DSU would be 

assigned to MissiG]) 724G, cmcJ it would record Mission 7240 data until one of the 

Mission 7167/7236 Sigl1al recognizers identified a signal of interest. When d valid 

signal recogl1itioll. occurs, the Mission 7240 analog output data would be interrupted 

and the DSU would be switched to the otiler payload for tile period of time required 

to record tile signal of interest. 

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TALENT·KEYHOlE TOP SECRET (,0,"00' HO TCS - 37562 - 71 COPY~._OF r; C:. C(H'1E5-

PA,('r. 6 OF __ ~ ___ "''' .. ;(S I (,0 "I HlO I SYSTEM r~rlUD[O fROM AutOMATIC PH;RADlh(, 

DOD [ll<lcrlvl 'i,'M; 10 ()or.,:- NO! "-PI'r'! 
Tep SE6RET TAlEHT-KEYHOLE 

4.3.2 Core Storage U fLit. 

have heen eSflcx:ia.lly 

share v:lth the vehicle healt!: sunlS ~den~e:~~:;:::3t[:-:~>: ,:,;' :::e t::~T':;c:: C::~_.~'" 

It is estirnated th~::.t the Z::lt.,;i gtI:t.:'_ d.te:d (~'Jyi \; ,";;-,l:"' !::·'~.,l1.l i:-~teT-,:.::e;}t ~:~l~':.~ 1 

in 'tNhich the target IS tr~.H:kL{~ frorr: r4J~:! t f

" ,:"1:.: iJ} '/, [Il I ',h!.',' ~:Jl\~' C;)(,-, C',; 

al:out 40 per..::ent of its tOLd cap<h': 

can be fully tracked. hetvieen esc 

is exceeded. 

5.1 Heceiver. 

Type: 

Frequency 

Banth.".:idrl1s: 

~arr(YNban.~:: 

\Videband: 

l"illTuwbami: 

Viideband: 

1" oise 

5.2 Antenna.s. 

I ntercept t.l1t:enJIH A ('J ~ to \} QG'~) J nz 

, -

Ga.in: 22 to 31 db 

Beamwiclth (.3 db); 3.3 10 10 

Intercept: Antenna (8 to 12 GHz): 

Gain: 31 to 35 db 

Beamwidth (3 db): 3.,3 to :. d."'OT'~'">'" 

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Steering Capabilities: 

Pitch (in-track): 

Roll (cross-track): 

TALENT·KE CONTROL S'tSl'EM: 

Nadir (0 degrees) to horizon 

(68 degrees) 

Plus or minus 30 degrees from 

nadir. 

There are seven pitch rates available. 

TOP SECRU [lCUJOro fPOM :.u!Cy..lI.T:C Rf:;';R,t.~fN(. 

DO~ OIlH,ClI'oiE 5100 !O OO[S or ~p.u~~ 

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