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ADP023963TITLE: The Myth of the Tactical Satellite

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TITLE: Air & Space Power Journal Summer 2006

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The Myth of the Tactical Satellite

LT COL EDWARD B. TOMME, USAF, RETIRED

Editor Note: This lite / died.f, a c n icl d e/c ded, filly ioie/ene pier etited "The Sti rteicNature of Tactical Satellites" aivadiabi cit the V/eb site of Maxwell Air Force Bases Aiip ower Re~search Instit te:http/s://esearclhrnaxwelfa rn/I papnis ay2006/CAi)RE t/ornrnepdf Whzile this article discuzsses the case of a snirz'eoptimized incw Erth orbit, the Inzger paper demonzstrates that the resuls discuzssed he areq :uite gennral. It dletniil lhe

optimiation techn/n~ue an*d its anclderly/ig cissuaipt/ns, discuzsses senzsor limitations in depth, rind dlebanbih coaiionarguments agai/st the study met hololg,.

Editoa-ial Abstrct: Many currnt pmpanents insist that "tactical" satellites ar a must-have assetsince they give the tactical war fighter a signifcant, palp able advantage in the battlepace. Calanelibmme, hawee; aigues that deveoping, fu~nding, and pradu~cing these satellites canstitute misdirectedattempts ta canvince field cammanes that satellte capabilities exist far battle id exlaitatian. Thzeauthar suzggests that these pmpa[)nents need ta shift theirfabcus tozaad the strateffc iealm, w~he measuirable satellite effrcts can be meaningfully iealized.

7T e wise are nat wise because they, make na mistakes. 7They are wise becauzse they, cawect thenrmistakes as saan as they, recagnize them.

-Orson Scott (ardXenzocide, 1991

8)

90 AIR & SPA (I POWVFRJO)RMAL S-I -E' 2006T HE CONCEPT OF operationally The myth of tactical satellites is that theyresponsive launch to get tactically are tactical. As currendy envisioned, there isuseful payloads into orbit quickly no mission where a tactical satellite can provideand cheaply has been around for primarily tactical effects. To use computer

many years Operationally responsive launch programming language, "tactical" is a reservedhas yet to be realized but is much closer to word. When one uses that word to sell a pro-reality. There is a definite need for a capability gram to a warrio; the warrior has a very specificto place inexpensive payloads into space on a understanding of what that technical termvery short time schedule, means-applying to small-scale, short lived

Developing tactica- useful payloads that events, usually involving troops in contact.can take advantage of responsive launch, how The ability to launch small payloads intoever, is a different natter. A combination of orbit on an operationally responsive timescale,physical corstaints placed on satellites by or howeve; does have its utility. The tactical satel-bal mechanics and operatonal eqoirments lite program needs a change of name and aplaced othei r pa Lads by the isions that change of focas, as the effects it can providecan be performed frm space prevents all but lie much closer to the strategic end of thethe most rudimentary tactical missions from spectrum of conflict. Such a change of focusbeing attainable for the foreseeable future, would allow operationally respons e launch toEven if these missions can be performed from compete in the strateg.ic arena where it actuallyspace, they will end up costing hundreds of has a great deal of utility. In his case, however,thousands to several million (ollars per hour tactical satellites appear to be a round peg in aoverhead, a cost that would seem to place them square hole-a soluion being forced into abeyond the reach of tactical or even theater mission where there are much better answers.commanders. Continued funding of the tacticalsatellite program under the misguided notion Backgroundthat such satellites can provide tactical effectson the ground only serves to drain scarce bud- The following table sunimatizes the opti-getary resources from other programs that can mized number of satellite passes, pass dura-provide the desired effects. tions, and gap times fbr one easonable circular

Table. Contact time and cost data for a 500 km circular orbit over Baghdad

500 km Circular Orbit

Mission Average Number Average Pass Average Gap Average Percent Cost perof Passes per Duration between Useful Time Over- Hour

Day Passes head (Duty Cycle) OverheadSINGLE SATELLITE

Signals Intelligence 9,7 7 min, 47 sec, 2 hr, 20 min, 5,6 $ 43K(SIGINT)

Communications/Blue Force Tracking 8,7 6 min, 12 sec, 2 hr, 39 min, 3,9 61K(Comm/BFT)

Imagery 4,6 1 min, 40 sec, 5 hr, 10 min, 0,5 429KFIVE-BALL CONSTELLATION

SIGINT 48,6 7 min, 47 sec, 28 min, 27,8 43KComm/BFT 43,5 6 min, 12 sec, 32 min, 194 61KImagery 230 1 min, 40 sec, 1 hr, 02 min, 2,7 429K

Note: The hourly cost tor s single sateite and s conste Iation ot satellites is the same in this table due to the fact that adding a secondsatelite doubles both the coverage time aod cost.

TH-I VMYI OPT-IFTA(TI(AI SA-T[ITE 91

orbit altitude, chosen because it is about as lead to a predeternined solution that will nothigh as any fumded tactical satellite Advanced support tactical satellites; these numbers areConcept Technology Demonsrcation (ACTD) those espoused by tactical satellite proponents.is designed to orbit) The paraneters used to As can be seen from the table, signals intel-generate these results define the tactical sate- ligence (SIGINT) and communications/bluelite progam as that term is used in this article) force tracking (comm/BFT) missions get sig-The goal acquisition price per satellite and nificantly better performance than imagerybooster is no more than $20 million each.5 missions. This difference is due to the severelyThey are designed to last between six months constrained field of regard (FOR) available toand one year to reduce the construction costs. imagery missions. Figure [ shows the relativeAgain, I have not assumed numbers that will FORs, the area on the ground that its sensors

50 above horizon- -.

10° above horizon --------- - -45° of n dir.................... ..... ......

......... - - .. .....45 off nadir---"*nad ir ..... ..... ........... ..

30" off iadir .....

500 k Orbit

497 km 1,42 knm ..230 km 387 km

Figure 1. Fields of regard from 500 km. While it may appear at first glance that there are two points ofview expressed in this figure (the ground-based point of view, above the horizon, and the satellite-basedpoint of view, off nadir), the terms actually describe the same information. For any given altitude, anysatellite-based FOR can be converted into a ground-based angle and vice versa. The conversion is acomplicated function that depends upon satellite altitude. The two terms used are the ones commonlyused operationally for the different mission types.

Note: In the upper portion at the tigure, the dotted lines represent imagery-related FORs, the dashed lines represent comm/BFT- restedFORs, and the said ne represents the SlGINT-related FOns The middleet portion shows the earth and a 500 kr orbit to scale Te

Mower portion sows an enlarged side view of the os he 500 k orbit The distance labeled a s the diference between theradius of the orizon FOR and the five degrees above h FrzoOR b: between ive and 10 degrees above the horizon FORs; c: be-tween 10 degrees save hrzan and 45 degrees att adir FORs; d between 45 and 30 degrees off adir FORs.

92 AIR & SPAtE POWERJ OUR\AL SI l E 2006

canr use, available to a satellite in a 500-kilometer nents, the goals of the generalized tactical sat-(kin) circular orbit-higher orbits would have ellite program appear to be to launch the en-similarly proportioned but larger FORs. 7 It ergy equivalent of a 1,000-pound payload intoshould be obvious to any tactical war fighter a 100-nautical-mile (185 kin) circular orbitthat the levels of coverage shown in the table Furthermore, the program seeks to keep it thereare inadeuate for tatctical needs. A tactical for six months to a year at an acquisition cost ofwar fighter needs persistent imagery. Getting about $20 million per satellite and booster com-a snapshot every hour or so is not very useful bined.' The results in the table assumed the useat the tactical level, where the timescale of the of an opimized orbit designed to give the maxi-action is measured in minutes or seconds. mun time for the satellite overhead, or contact

SIGINT and comm/BFT missions are sim ti n By optimizing the contact time, we alsolarly ineffective from low Earth orbit (LEO) maximize the average number of satellite passescircular orbits. It is almost inconceivable to per (ay, naximize pass duration, minimize thecontemplate sending commanders into com- amount of time the satellite is not overhead orbat after telling them that they would only be gap tni, and minimize the cost per hour over-able to communicate five minutes out of every head. These orbits are not necessarily the oneshalf hour, A larger network similar to the 66 that are used operationally, as those orbits maysatellites in the Iridium constellation can pro- be optimized for different constraints such as aitde good coverage, but even at a relatively constant-solar-illumination angle. However, these

inexpensive $20 million per satellite per yea, orbits give the absolute best cases for time andthe expense of such a network exceeds the cost; all other orbits will necessarily give less timereach of the tactical commander.' and will cost more per hour overhead.

In this article I will present the tactical sat7ellite progran in the best light possible. I willassiume that the satellites r , the Physical Constraints oncan he placed at will ibe the demned, optniied orhits; Orbiting Objectsthey will meet cost and lifetime goals; anti the as-

snmptions made ahont 'F)Rs wl he as genemvus as There are a number of "truisms" associatedposSihle. I will also assme peect environmental with orbits. They are presented here withoutconditions so the onhoaid senson will always he ahle proof. First, to optimize contact rine, the incl-to peijoim their $II , iniagely, connnnieatioin, nation of the orbit should be very close to theand BE nissionzs. ihe goal s to show that een latitude of the target. Second, increasing thewhen all sy stens work hetter than advertsed, the toe- orbital altitude increases the contact time."tical satellite piograni stil ails to pinvide tactical This result is due to two causes. One can seeefects oii the giud. T hese generous program- farther when one gets higher." Increasing alti-matic assumptions will demonstire that the tude physically increases the size of the FOR,failure to provide effects is not due to engi- which in turn has a posidve effect on contactneering shortdalls, where more money might time. Additionally, moving to a higher orbitsoe the problem, but is due to physical limi- slows the satellite down a bit, more closelytations that cannot be overcome until the sat- matching its speed with that of the earth's ro-ellites become inexpensive enough to field tation. The FOR thus moves more slowlyconstellations of huntretis simultaneously. By across a target, also tending to increase thepostulating the existence of a perfectly work- contact time. Finally, it is a truism that targetsing technological product, we can then con- near the equator and the poles receive bettercentrate on evaluating the operational-utility optimized coverage than midlatitude targets.part of the problem. As discussed above, a tactical satellite's orbital

What is meant by a "perfectly working tech- parameters will be limited by the energy thatnological product" is a point worthy of discus can be supplied by the booster. A booster thatsion. From various briefings and pubuishet can put a 1,000-pound payload into a 185 kmarticles attributed to tactical satellite propo- ci cular orbit could also put a 500-pound pay-

1-I tH MlY-I OP-ITACItCAl SA-TLIT 93

load into a highly elliptical orbit with a peri- Communications, BFT, and imagery mis-gee of 300 km and an apogee of 8,000 km) 4 If sions are different. They cannot use the hori-properly oriented, such a "magic orbit" will zon FOR. Tactical comm/BFT capability hasoverfly the same point on the earth once per day to be there all the time. Comm/BFT providersand can provide a huge, slowly moving FOR typically require their platforms to be at leastduring parts of its orbit, resulting in hours per five degrees above the horizon, with 10 de-day of coverage instead of mere ninutes.' grees being more commonplace. While this

We now have a good idea of how to opti- requirement does not guarantee coverage inmize a satellite's circular orbit to obtain the the bottom of a deep canyon, it does ensuremaximum contact time over a specified tar- that the odd tree, house, or hill will not nor-get-put it as high as possible and match its mally interfere with direct LOS to the platinclination to the desired target's latitude. To form. As seen in figure 1, restricting the FORoptimize a magic orbit, we only need to make to five degrees above the horizon has a signifi-sure it is oriented properly in space using a cant effect on the performance delivered byspecific set of orbital parameters. For the re- an optimized orbit.mainder of this article, I will assuie the use of Imagery sensors are even more tightly con-orbits optimized to maximize contact time. This strained. Not only must they have LOS likeassmnporodifarther einaie that we exanane the the other missions, but they cannot look toooperational ntilit5 ofthe tactical satellite concet in far away from the vertical (nadir) without inthe heit posible light: a platform that pei t eets troducing a host of problems. These problemsproam goal and ha heeii aneiiched into aii oPrit include foreshortening, excessive atmosphericthat gives it the best chace for tactical s. ccesd, tegradation, and decreased resolution that

can make analysis exceedingly difficult, if notimpossible. Additionally, many imagery sen-

Sensor Constraints on sors operate in the visible-light region. It is

Optimized Orbits extremely difficult for these sensors to func-tion at night. Even night capable infrared sen-

As shown in figure 1, there are a number of sors have a hard time penetrating significantFORs that can be applied to a satellite in any cloud cover.orbit. These FORs are based on the designed Figure 2 shows the end result of the combi-mission of the satellite. It would be nice to be nation of orbital and sensor constraints for allable to use the huge horizon FOR all the time, latittes on tactical satellites in 500 km orbitsbut it is actually valid only for a few SIGINT optimized to maximize contact time. Choos-missions. For other SIGINT missions as well as ing any other orbit to achieve required mis-for the communications, BFT, and imagery sion goals will necessarily decrease coverage

i ssions, it is not. The reason the horizon and increase cost.FOR is not generally valid is due to sensor re- The results in the table and figure 2 ignorequirements. For SIGINT, communications, the nontrivial limitations of weather and dark-and BFT missions, the emitter of the signal be- ness and present optimized numbers that re-ing detected must have an unobstructed line flect an ability for imagery sensors to operateof sight (IOS) to the sensor on the satellite, at full capability 24 hours a day/seven days a

SIGINT sensors can take in and analyze any week (24/7); this assumption significantlysignal tey can detect. Thus, there is generally no overstates the actual capability.requiement for them to be a certain angle above

the horizon. If the ter ain is flat and they can seeall the way to the horizon, great. If there are The Operational Utility ofmountains in the way, the sensor simply waits un-til it establishes IOS to the emitter ant then be- Optimized Tactical Satellitesgins collecting. For these reasons, I assume the It is now time to examine space missionshorizon FOR is valid for most SINT -missions. and compare the requirements placed on sat-

94 AIR & SPA(,' P)OWMR J()RA S-VIME[R 2006

Data for Optimized 500 km Circular Orbits

o , PASSESS ' 30 oiL eadr GAP

S or hoso n*" 45lt5 10oe h rrzo r . 6*.

/300oitnadir 4r# 2.O,# 6 10" abv ~do

- --- -~ - in--------------} "............-.

.. ....

0 109 0 l0 10 20 30 40 50 60 10 00 50 0 10 20 30 40 50' 00 70 50 0Tergew Latlo tu~ dseenl 1*5ge Loehuds aegree

1IN,

COST 1o ee h COST10, ........... -- (EXPANDED)

/# --------- t

01 / 0

45 Os nadr0001000

0" 40 44

O 40

0 02 04 06 08 0 19 ,2 I 000 44 7080

Figure 2. Number of passes, averag gap time, ad -ost data for atica Saeit in a 500 km orbit.

Note: The curves represent data for three 1iso t ypes: SIGINT (od), com/BF (dshd), and image ry cioted). Cost data areshown in two panes as the scales between imgry ad the ote miss r are qu i at.

ellites Aith the constraints we have strdied to ronmental monitoring; communications; andthis point. US Joint space doctrine spells out; precision nvgation and timing. In this sec-four primary space mission areas: space force tion of _he _-_dy I Ai11 attempt to find niches

application, space suipport, space control, and in these mission areas for which tactical satel-space force enhancement. " Space force appli- lites are suited.cation consists of attacks against terrestial tar- Space force application is not affcted bygets by systems operating fr'om or through the preceding discussion of orbitalopizaspace. Space support is the mission area thatinvolves cradle 10o-grave support of on-orbit as-sets. Space control ensures friendly rse of space

while denying it to adversaries and includes mass of weapons such as lasers that could haveboth offisive and defensive measures. Space an effect on the planet's surface would beforce enacement mu ltiplies J oint force ef- much greater than the 1,000-pound tacticalfect'vns trough heightened battlespace satellite reference mass. Conventional inter-aw"arees It inclades the function of intelli- continental bLiTi'c missiles could possiblygence, s eill;ce, and reconnisace (ISR); provide fc-e-applcatin effects within thetactiure 2aNmg o ndase avege gat; envi- weight rage o t tctical satellite booster

H-IFIEMi- OPT-IFTA(TICAI SATL [IT 95

but they are not satellites and will not be dis- clear detonations to the president and secre-cussed in this article. tary of defense. This mission is currently

I ikewise, space support is not a mission performed froni geosynchronous Earth orbitthat has been discussed in the literature as a (GEO) by platforms such as the hantiful ofmission for tactical satellites. Space support Defense Support Program (DSP) satellites 1 7

from such things as launch facilities, opera- Such a mission would certainly be impossibletions centers, and the space communications frtom LEO without a constellation of hundredsand control network will be required for con- of satellites, as it would require continualstellations of tactical satellites, but it will not monitoring of the entire globe. While tacticalprovide a tactical effect to warriors on the satellites in magic orbits could conceivablyground. Tactical satellites will require space perform the mission, it would still take be-support but will not provide it. Note that I do tween 12 and 20 of them to provide continualnot include the cost of any of this required global coverage, at an acquisition cost of atspace support in my cost calculations, as it is at least $240-400 million per year-a cost c om-present a relative unknown compared to the parable to a single DSP bird, which is de-postulated $20 million per booster and sael- signed to last much longer. The mission islite quoted by tactical satellite proponents. also undeniably strategic.

Spare control certainly seems to be within The envionmental-monitoring mission pro-the puirview of the reference energy (orbit/ sides data on space and terrestrial weathermass combination) of the tactical satellite pro- that could affect military operations. The De-gram. Being able to responsively launch a sat7 fenseMeteorological Satellite Prograi (DMSP)ellite with the capability to maneuver in close platforms are one part of the curre nt imple-proximity to other satellites would be a boon mentation of this mission element." Tacticalto those tasked with exercising both lethal and war fighters rely heasily on DMSP informationnonlethal shutter control on the space capa- to help plan hei actions. Likewise, executionbilities of hostile nations. However, such con- of the precision navigation and timing spacetrol is unquestionably a strategic mission with mission element through the global position-immense political ramifications and global efi ing system (GPS) gives war fighters an enor-fects. Employing it may provide advantage to mous edge on the battlefield. GPS birds orbittactical war fighters on the groundn-many much higher at about 11,000 kin, making anstraegic actions io-but the advanrage will be orbit about every 12 hours.1 Both systems areindirect. Thus, space control from a respon- unarguably strategic, though, and replace-sive launch platform will not be discussed fur- ment would not be the job of a small numberther, since we are concerned with providing of tactical assets. Additionally, were the DMSPtactical effects on the ground, or GPS constellations knocked out of service

After examining and eliminating the first by some hostile act, it is dif icult to imagine athree space missions fion consideration, one situation where constellations replenished bysees that the only remaining space mission for responsively launched assets would be any lesswhich tactical satellites appear most useful is sulnerable to whateser brought the originalspace force enhancenient, the traditional role of systems down.most satellites. In fact, this mission appears to be In contrast to the three subelements justthe only one discussed to any degree in the lit discussed, the ISR and communications mis-erature dealing with tactical satellites. We will sion subelements do appear to hase a need forexamine each of the five subelements of space tactical enhancement. Unfortunately, the cost7force enhancement individually below, tising performance constrints of any responsive-the circular LEO and magic orbits discussed launch boosters ens isioned in the foreseeablepreviously as baseline points of reference, future make tactical satellites poorly suited to

The tactical warning and attack assessment be the source of that enhancement. I will dis-mission deals with providing timely notifica- cuss these constraints first in relation to circulartion of enemy tise of ballistic missiles and nu- IEO antd then magic orbits.

96 AIR & SPACE POWER fJOURNAL SI VER 2006

The primary limitation to all tactical satel- To get 24/7 persistence from even alite applications from IEO is the very rapid SIGINT mission at 500 km would take a con-passes of a relatively small FOR. LEO satellites stellation of about 80 satellites./ 2 It is quite evi-do not and cannot provide persistence, an ef dent that even at the relatively inexpensivefect of paramount importance to warriors on projected cost of tactical satellites and theirthe ground. This limitation is a severe con- projected lifetimes that these numbers makestraint even for the best case horizon FOR. persistent tactical satellite presence unafford-From the ruisms (Liscussed above, it is obvious able. The acquisition cost of such a systemthat to mitigate the rapid FOR pass, one would be at least $1. 6 bo each ear. It is forshould move to a higher altitude. However, just such reasons that tactical satellite propothere are drawbacks to this solution in addi- nents instead propose very limited constella-tion to the reduction of payload mass in the tions, usually of five or fewer satellites, to pro-energy trade for extra altitude. vide what they call "tailored persistence."

While increasing the contact time and reduc- Such persistence is obviously stroboscopic ating the cost per ho -r overhead, raising the alti- best, providing a flash of utility periodicallytude has a negative impact on signal strength. with large gaps of blindness in between.Using the basic 1/r2 law for the attenuation of On the other hand, even the relativelyan electromagnetic signal, one sees that increas sparse constellation of five satellites discussed

ing altitude enough to significantly affect the above would make such enemy communica-

FOR pass rate even more significantly decreases tions and movement blackouts extremely

the signal strength received by the satelliteJ2 difficult to employ for their strategit opera-

Large antennae for reception of radio sig tions-operations where the le is long

nals can be manufactured relatively easil, and compared to the revisit rate. In most foresee-

they are a relatively low-mass portion of the able situations, it would appear to be counter

payload. To double the signalcollecting ability productive to stop operations this frequently.i e tOn the other hand, for tactical engagements

ofan atn t is (0 t e where the timescale is measured in minutes orthe antenna area, so compensating for the de- seh th a heasee uesit

creaed igna stenghs i mot LE orits seconds, much shorter than the satellite revisitcreased1 signal strengths in most LEO orbits aetho eea1ifmtonillie)bdoes not require an insurmountable increase raethovhadifmtonwllklyb(ieno easi. T e aa itnmonabizes deae too late and too sporadic to be of much use toin mass. T he actual antenna sizes dlepend1 friendly forces. "Tactical" satellites thus em-upon the required received signal strength, ployed in IEO for SIGINT and imagery ap-which is highly variable. Thus, it appears tech- plications appear to be much more useful fornically doable to put optics and antennae in strategic missions.IEO on tactical satellites. The budgetary numbers associated with

That said, it remains for us to determine tactical satellites greatly exceed the costs ofwhether the effects provided by satellites in puting existing manned and unmanned airthese LEO orbits are valuable to a tactical war craft or proposed lighter-than -ai nea spacefighter. The primary factors involved are, in assets over the battlefield. The persistence thatdecreasing order of importance to tactical these nonorbital platforms prov ide could bewarriors, coverage opportu ities, coverage truly tailored to the pace of the battle insteadtime, and cost. 7b be trul isejul to a tacIcal war ofging pseudorandomly timed stioboscopic

fighte; ects have to beleft irside of the decson flashes of insight 42cycle ofthe enemy Information must be provided The abo e discussions deal with the SIGINTrapidly enough that it can influence the next and imagery missions, where even the sparsefriendly mov e before the enemy has time to information provided by a small constellationreadjust.f The table clearly shows that even at could be of some use. On the other han , sparsethe 500 km altitude over Baghdad, the gap constellations of satellites in IEO have notimes are much longer than the timescale of a chance of providing a useful communicationstactical engagement. capability. During an engagement, communi-

H-IV MlY-I OPT-ITACIXTAI SA-TE [LIT 97

cations are needed when the warrior needs rapidly moving satellites. At their average dis-them, not when they are available. The tail tance above the horizon, magic orbits are 11can't wag the dog. Sporadic, pseutlorandomly- times further than even the Iridium constella-timed communications capabilities will not tion. The signal reaching them from the grooundsupport a tactical mission. Tactical command- would thus be at least 120 times weaker. Sinceers need the information available to them weight is a huge factor in getting to thesewhen they need it, not when the sensor is avail- higher orbits, increasing the size of the anten-able to give it to them. nae to about the required 200 n 2 does not

Apparently, tactical satellite proponents de- seem feasible. Without significantly larger an-vised the magic orbit to counter the IEO cos tennae on the satellite, the ability to use whiperage problem I have just discussed. The rela- antennae on the ground becomes problematictively long hang times over the target mean and would most likely require the use of thethat five or six satellites could conceivably pro- familiar small dishes to increase signal strength.vide the 24/7 persistence that is unafforlable However, the use of a high-gain dish an-fronre LEO. This solution attacks only one of tenna is even more difficult for communicat-the two constraints on getting tactical effects ing with satellites in magic orbits. As discussedfroi space--orbital mechanics. By moving previously, it is currently difficult and there-much further away from the earth in an at- fore operationally prohibitive for troops ontemplt to slow down the satellite passes, this the move to stop, set up a dish antenna, andsolution compounds the other constraint point it towarc the stationary commnnicationsthe payload's ability to perform the nIission. satellites that currently exist. This difficnl is

Using the 500 km orbit as the baseline, significantl compouncde when a moving7satone finds that the average magic orbit dis- ellite in a magic orbit has to be found andtance from the target is 17 times further than tracked in the middle of a tactical engage-the IEO. As an example of a specific effect on ment. In contrast to the soldier on the groundpayload performance that such an increase in who needs to manually point his antenna,range will have, to get a one-meter optical im- many unmanned aerial vehicles (UAV) are al-age of Baghdad from the average magic dis- ready controlled tlrough satellite links. It seemstance of 8,500 km would take at least a 5.1 tre- feasible for these links to be through satellitester optical aperture (the size of the large in magic orbits. Howeec the severe environ-telescope mirror at Mount Palomar Observa- ment inherent in this orbital regime will likelytory in California) instead of the 0.36 meters be the ultimate arbiter of success for any magicrequired from 500 kmi For this reason, it orbit solution.would seem impractical to use the magic orbit The requirement for satellites in magic or-for conventional imagery applications, bits to regularly traverse the inner Van Allen

Similarly, a communications or SIGINT an- belt will call for some mitigating engineeringtenna in a magic orbit would have to increase design to ensure that the one-year goal life-in size to be as sensitive to signals as its IEO time can be met. This mitigation can cone incorinterpart. Satellite communications on the one of two ways: by using radiation hardened,move is a highly desired capability in the space-qualified components or by adding ad-fieldl Many people are familiar with satellite litional shielding to protec the cheaper com-phones with their simple, easy-to-rse whip an- mercial off-the-shelf electronics. The firsttennae. These phones are generally run method will almost certainly carse the budgetthrough the 66-satellite Iridium system orbit ary goals of the program to be exceeded. Theing in IEO at about 780 ki. Iridium satellites second method will add significant weight touse a set of three 1.6 square-meter (m2) anten- the system. Neither solution seems palatable.nae for receptioni 7 Having the satellites so It is a physical fact that the constraints in-close to the earth in LEO is the reason that posed by orbital mechanics and those imposedthe phones can employ antennae mat don't by sensor limitations work contrary to eachrequire precise pointing at and tracking of the other. Choosing a higher orbit that slows

98 AIR & SPA ( POWER JOURMAL SI 'ER 2006

down the satellite pass to improve persistence ground on a timescale that is less than that ofends up requiring huge increases in payload a tactical engagement.physical size, mass, and cost in order to main- All is not gloom and doom for the tacticaltain the standard of performance. It is an in- satellite program. Many of its goals are ex-terestin g "Catch-22": put the satellite low tremely worthwhile antd vll definitely benefitenough that it's affordable, and it's only mar- the nation and its defense. Standardizing bus-ginaly useful due to limited pass times, but ses and dev eloping plugi and pla payloads willput it high enough to be useful, and it's no do a great deal to bring the cost of space eflonger affordable except at the strategic level. fects down to earth. Being able to launch re-

Even with the favorable assumptions I have sponsiel wAill have a huge impact on spaceused in this analysis, it is clear that the ability contol options available to the national leader-of tactical satellites to deliver tactical effects is ship. Being able to provide very cheap aug-severely limited. Less optimistic (and more re- mentation to expensive, hard-to-reconfigurealistic) assumptions would further tip the bal- national assets would be a boon to strategicance against the utilit and suitability of tactical planners. Being able to cross-correlate infor-satellites for tactical applications. As I have mation from GEO and IEO birds for shortshown, there are severe physical constraints time periods will make many strategic analystson satellites in circular I, EO and elliptical extremely happy. It's not the program that ismagic orbits that conflict with tactical mission bad; it's simply misdirected. B -using the wordrequirements. It seems highly impractical, if "tactical," proponents lead warriors to makenot impossible, to perform tactically useful unsupportable assumptions about the prog'am'simagery, communications, SIGINT, and BFT actual capabilities. Their focus needs to shiftmissions within these constraints, especially if toward the strategic where the effects they adcost remains a consideration. vertise are possible to achieve and are useful.

In the end, it is much more appropriate formythical ta cal satellites to compete for fund-Conclusion ing against other strategically oriented pro-

Tactical satellites as currently defined by grams. When they compete with and win fund-proponents aren't tactical. lust having a tacti- ing against programs that actually have thecally responsive launch rate, if achievable, potential to serve warriors on the ground, theydoesn't make an asset tactical.just being much detract from Congress's intended budgetarycheaper than other orbital platforms does not goals. Continuing to fund tactical satellitesmake an asset tactical. To meet the program out of budget lines intended directly to servegoals briefed by tactical satellite proponents the tactical war fighter does a disservice toto senior military leaders, a tactical asset must both the taxpayer and the warrior on thealso provide tactically relevant effects on the ground. J

Notes

1 For example, see MLj Richrd A. Hand, MI j Bonnie iUg th simaks H~h ou d: *Vx1 Sups in 1he 1h1) U ofHoucen, and M ,aj ou arson, eds Vma Haudboo: A pacI, RAND report TR1649 (Santa Monia, CA RAND,flfu Flqhhi (uIde Io Sacf, wol 1 (Maxwell AtoB, A Air 2003), 45U niv ersity Press, 1993). 3. "TacSat-2/Road ?unnei MJicro Satellite Fact Sheet,"

2. Air Force Tactical Exploittion of National1 (apabili- February 2006, http://wwwxvs Ma f mil/FactSheets/Rod

ties has a mission Of tinding tactcall) relevant uses or Rnationa1 assets, inluding satellites, Wil many nac4 inatuses or satellites are possible, the global nature of or for Responsive Space aunch Demonstration trderbit makes the primary mission of these satellites stiategic DAR PA FA CON Program," SpaceX Web Site, 20 Septembei"Air powxei can be global in its reach and ability to impose 2004, http:/www\ spacex com/index html~section-media

efecs on an opponent, Ihereas space powei, b, its very &content-http% 3A//xwspacex com/press Ilphp (ac-nature, can onIy be global" Benjamin S Lambeth, 1a cessed 6 November 2005).

1- MF-I O1F THEITACTICAI SAlT!LLI7V 99

4 There is no all-encompassing tactial satellite pro- Space mploytent (or Joint Wirfare" (briefing, Jointgram; intstead, ther e ab tnber of researrh efforts he Forces Command (rit Space Conrept Developtent anding conducttedl by Air Fotrce Spire Cotandr's Space antd Experitnenation Workshop, Notrfolk, VA, 31 Masrrh 2004),Mlissile Systetns Centet (AF'SP~C/SMC), the Air Fo~trce Re 1ii Data (tsr cirulir ortbits romputedi by the author its-searrh Ishorntors (AFRI0 the Defense Adv ancedl Re- ing equanootio s ie in MI WI Io, 'The Iong 'Tert Fore-search Projects Agency (DARPA), antI tothers, The goals cast tof Sttiti Vtetw Periods,"1i l7rircrbtoamnw:ttm ntd Da/nantI paratneters cquotedl thrtoughottt this article are gener Acqnzton Pingis Rrt 42-11I8, Apnil-Jfnne 1994 (Pasirdena,

alizer numbers basedl on0 ntumnerotis sources cited below CA Jet Propulsion Laboratory, 15 August 1994), l-13,5.In 2004 the advsertisedl haseline etost for a tactial http:itojpl nasa gus progress repot/ 42-i18/l18J.prlf

satellite antI lauinrh was $1i5 millin DOD, Ojirt/tnttlb) (aiccessedl September 2005), antI MI W iso, Apphdcntno offRunosie 5)Pncr Erp/rimtort IcSn/ -1, 1S Goserninent IEgnric /throt1 In (;oertngr Atain/sI, Paper iso AAS 03-638White Paper (Wasshington, DC: DOD) Oftire o~f Frcre (Big Sky, MT: Proreedings of the AAS Astiorlynaiis Spe-Transformation, 17 Orctober 2003), 2. By early 20105, the cialist Coinference, Atugtust 2003).

prire was being qtoe as $20 msillion to $31) msillitn 12 This truism is acttally oily true to certain alti-Anty Passitosr, Pentagon Enisions Operions witb Small tudes At a height at shirh ote can almost see an entireSatellites,"l~nt! S'd/trrJon~/, 26 August 200: The current hemisphere, raising the altt re flither only marginallyTacSat 2 isill crist at least $50 million, barring fiti ther increases contact time. Ardditionally, the absolute max]iproblems. (ol Pamels Steiart, AF-SPC Diretrinate of Plans intti cotiacti time wou~tld occrt sshen a geostationary sat-

anti Requirenents, Responsise Space Nest-Thins Plan ellite is in Iiew; that contact time would be 24/7 Moving(briefing, Air Forre Srientifc Advsisotry Boarrl, Coloradlo higher itan geo~synrhriotous Earth oirbit actually dlerreases

Springs, CO, 27 April 2004) See also sol Rex Kiiah, cwireitr a ealing tit tactial salAFR , "Jinst W rhghsting Space" (brieisg, Schriever I lites in LEO fir this stdy, thigh, tsese liit ns onWar Gaise, Nellis AF-B, NV, 8 F'ebruiary 2005); antI Joint thse tuisin doin't rcomse ists play,W arfighstiig Space: Nost (Just) ais ldea, Nost Yet a Pro- 1 est aistftle(esrttiayObtthe trils el, assofteGo tiarObt"

t 7f i hs Seldsisr toespisisss Spae Cif s A iof he ecod Rspnsie SaceConernce Amricn sisoly about 42 perceist tof ilse glisbe aisr cannioit see losaostttre tof Aerosnatiis aisr Astrosnautiis, 10-22 April 200)4), in ihlttdshihrta 1dgesaisr M1a1 Scisti Cook, AF-SPC Directosrate tof Plaiss aisr Re- rttssil aitre lgsttsm 1reiequtirettents, 'Tactical Satellite (TacSat)/lutist Wartighstiig 14. Jasmses R. Wet i, "Cmverage, Resposnsiveness, aisrSpace ((1IW5) Demssstsratiosn Prosgraiss (briefing, Headl Actcessibility fist sVartistus 'Resposnsive Ortbits,'" Paper isisqutarteis AF'SPC, Petersion AF-B, CO, 6 Janutary 2005). RS3%200-201)2 ( os Asgeles: Proreedlings osf the Thsird Re-

tCiss S ciitseeir iseias istiie1) et7. Thse results presensted its itse table are basedl on sporr Spac ofrne rcnIsiueo eo

qutiie toptitnistir tieldls tof regardl fistrshe dlifiereist miso isatitcs aisr Astroiauttirs, 25-28 Apriil 200)5), http:/inww

ies

types: hoizoiin tr SICINT, hie dlegrees shine ilse hosiriion rept)issespare ct)i/s apers/ RS.}rr5CSESSlONr _(1PAPER.Sfist coisissBET, aisr 43 dlegrees tiffnisr fist imiagery, Thse %SCSESSIONrr202rrSC2001 WERTZrSC201 prlf (aic

isutinbers besme muihs less faorable sseis orereal Novembe r 2005,)srl Ne)1. Rics Tuttle, Air Fore Strdies Uiiqre Orbit fistr cosssmstiiicationis aisd 31) degrees osff nisrl fist issagetr)) Proijectedl Fairoily if Sisall Sats, .\)r/r)tors, Il Masrcs 2004.

Costi data are baserl tot itse fhill year osf seivice aisr itse $20 16. (titu Publicationi (JP) 3 14, Jeoit t)oc/tutt Jot parcmilliom acqutisititoi coist onily, swithouti t htosritsg its isfr'ao Orrdtit, 9l Auigrist 200)2, ix-x, IV-5-IV-I10, aisr A 1-E-4.sitrcture, dlaily osperationts, tsr peistotisel ciss lisfitirao 17. Defeisse Stippisri Prosgram Satellite Eaci Shseet," 96nits ott hows itse nsutmbers ssre dleriv ed asrntil issis moe Ocitibet 2(0, hsttip/spateait afitl/ hrcshseets/dlsp lhtidletailed obitaloptimiztatin tcalcitlauoins ate pu i rovied in 18, Deteisse M etetorgicral Satellite Prosgrais Fatthse hittget sversiton tif this article. Slseet," 26 Octisbet 2003, htip://space art af intl/factslseets/

8, Irirdirit Satellite Web Site, 12 Ntisember 2003, rlisis lsrishitip:ss/sswirliitm risin 190 Naustar Gloibal Possitioiing System F-act Sheet," 26

9) A bostr rais supply a rerraits sisamut tof eineirgy ts Octosber 2(00), htrtp:/space iu af isil/factshseets/gps lhutsa satellite That etsergy is a soiisewhast costiplirater comisbi 2(1 Irdeal electroisaginetic swases proipagate as spheiresisationt tof thse satellite's altitire aisr tiass The bosirs tsr ansgular sectiiois tif sphleres, Thse it area tof a spliete is 4nrcrirrestly enivisisosedl fistrlse tarctical satellite pirograin, t 3K As ilse etiergy cosisalised at aisy patrtlar wiase IrntDARPA's FA CON antI SpaceN's F-alcoin 1, bisil hsase thse must retnains conistiatnt iiietrtise, itse itensity tif the wiaveapprosxiimate capability ti Pitt 1,00)0 pourinds its a 100(1 at aisy pintt tit thsat wiase fittit must dlecrease its cisitirrisiiauctisile torbitr They cats pitt lightrei payhtiars iuts ilse sphseiical iscrease its itse wiase (t area. Thsus, as ilsehiighser tirbits is loiig as itse coitmbiniatiosn tof payloiadl sass wuase fiin area incrreases as t , ilse itiretsiy must dlecreaseaisr tirbiral altirire is less its ilse eisergy asvailable (rin as l/rilse bootsrer, 21. (tihn R. Boyr, "A Discourtse tit Wininiig aisd iiis

1(1 Kiiiahs, "Jitit Warfighstitig Space"; aisr 2apst Beth ing," Air Uniisetrsiry Library dociumtet isis MU 4 39)4 7, ArtStargarrdt, AFRL Space Vehsirle Dirertosrate, "Tactiral guist 1987. Unpusrblishsed brieing isises aisr essays.

1 0 AlR & SPA CE POWE[RJOT7NAL StL VEER 2006

22, By ron Hay's, I-&ponsi&w 5V)W{ac¢/wcal 5"aI e L lid), mlore complicted thn that, For this reason, I will use theA nayis (briefing, Brig Gen William Shelton, director of tecm sdo~andoin to desciibe the pattern of satellitePlans and Polic, U S Straecgi Command, April 20b4) passes ov e a spot on the eartho

23, Kiah, "Joinlt W arghtng Space" 2: The wavelength used for this calculation was 40024, Orbital passes arc not actually randomli diseiib- naometeis (midle of the visible region) Distances were

uted, the) arc, in fhct, quite wxell dletermineed, especial} based on the slant range from the satellite to the edge ofwxhen highly variable per tuirbations such as atmospheric the FOR, The actual optics requircd to achiev e the stated

drag are neglec tcd However for most o bits, the pattern resoluions would be large, as thc diffraction limit isof repetitionl fo~r the satcllitc passes is not easil) discerned based on theoretically pcrfect seeing conditionlsb) the warrioi on thc groundI Unless the orbit has bcen 26, David Hard), "TacSat Demo Status: Senior Leadci

specificall) taicd to do so (am in wh ase the satel Vcctor Chek (bricfing, AFRk Kirtland AFB, NM, 22lite will not be providing the optimized maximum cocr- Sceember 2004)age timc), the warrinor cannot say, for example, "xi ]l get 27, Visual Satcllitc ObseiN cr's Web Sitc, "(tch atwo( passes a dlay oncm at noon and onc at midnight--for 1Flarinlg/(linilg Iridium" (updated 6 Marhi 2002),the next twxo weceks" The pattcrn of rcpctition is v astl) hetp:/satobs org/inidiumnnl (acfcessed 26 Octobci 2005),

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