The Economist - USA (2022-01-29)

6 TechnologyQuarterlyDefencetechnology TheEconomistJanuary29th 2022

agenciesinAmerica,CanadaandEuropeusedthetechnologyfor

variousenvironmentalmissions,butnotasa routinewayoflook­

ingathumanactivities.Itwassimplytooexpensive.

Advancesinelectronics,spacecraftengineeringandon­orbit

computationmeanit isnowpossibletoputsarsystemswithres­

olutionsofa fewmetresorlessontosmallsatellitesata reason­

ableprice.In 2018 twostartups,CapellaSpace,inCalifornia,and

iceye, inFinland,launchedcommercialsarsatellites,andthe

fieldisnowbooming.Realisingthattryingto stoptheboom

wouldbepointless,asothercountrieshavesimilarcapabilities

anyway,thePentagonhasencouragedit—inpartbecauseit greatly

increasesitsowncapacities.

Kingsofheaven

JackO’Connor,whoretiredfromAmerica’sNationalGeospatial­

IntelligenceAgencyin2013, saysthatbackwheneverythingwas

classifiedtheamountofavailablesarcoveragewasnotsufficient

forthesortofanalysisthatisnownormal.Moreforeveryone

meansmoreforthespooks.“Ifyou’reina professionalintelli­

genceagency,nowyouhaveadditionalsourcesandyoucancheck

theorbitstoseedotheygivemecoverageattimesandinplacesI

couldn’tgetbefore?”

Thoughintelligenceagenciesandarmedforcestendnotto

bragaboutwhatthismakespossible,othersarehappyto.Russia

hasbeentestinga nuclear­poweredcruisemissilewhichnato

calls“Skyfall”atfacilitiesintheNovayaZemlyaarchipelago, high

upabovetheArcticCircle.Andasthe“ArmsControlWonk”pod­

castputitinthetitleofanepisodelastSeptember,“It’salways

cloudyinNovayaZemlya”.TheepisodewasaboutthewaythatJef­

freyLewisoftheJamesMartinCentreforNonproliferationStudies

attheMiddleburyInstituteofInternationalStudiesatMonterey

andhiscolleagueshadusedsarimagesprovidedbyCapellato

showthatnewtestsofthesystemwerebeingprepared.American

intelligencesourcessubsequentlyconfirmedtocnnthatthey,

too,hadclockedthepreparations.

Theabilitytoseethroughpoorweather,dayornight,lendsit­

selftotrackingthingsthatarechangingovertime.Amilitary

build­uplikethatontheborderofUkraineistheperfecttarget;the

imagerymaynotbesharpenoughtoidentifythespecifictypeof

tank,butit isgoodenoughtocountthenumberofthem.

Andchangesata specificsitecanbeanalysedwithremarkable

precision.Radarsystemscangetdatafromthephaseofthewaves

theyareusinginwaysthatopticalsystemsusingambientlight

cannot.The“coherentchangedetection”thisallowscanshowup

evenminuteanomalies.WhenAmericadiscoveredthatit waslos­

ingmoreofitssoldiersinIraqandAfghanistantoroadsideieds

thananyothertypeofweapon,boffinsatSandiaNationalLabora­

tory,oneofthefacilitiesresponsibleforAmerica’snuclearweap­

ons,developedCopperhead,adrone­mountedsarsystem that

usedthissortofchangedetectiontospottinydisturbancesinthe

soilwhereinsurgentsmighthaveburiedieds orthecommand

wiresthattriggeredthem.Similartechniquesallowsatellitesto

revealtheslightsurfacesubsidencewhichcomeswiththebuild­

ingoftunnelsfornucleartests.

Detectingverysubtlechangesovertimeisusefulforintelli­

genceapplications.Detectingblatantonesastheyhappenisuse­

fulforwar­fightingones.Assessingwhetherbombshavestruck

thecorrecttargetsandwhatdamagetheyhavebrought about

needstobedoneasquicklyaspossible,lesttheothersidecleanup

orobscurethesite.Indiauseditsburgeoningfleetofsarsatellites

forjustthispurposeafteranairstrikeonPakistaninFebruary

2019.America’sairforcedidthesamethingintestscarriedoutin

December2020,pointingexplicitlytoweatherconditionsinEu­

ropeandthePacificasthemotivation.

Dwellersallintimeandspace

Beingabletoseea siteona regularbasisregardlessoftheweather

alsoallowsarmedforcestocreatearchiveswhichwillonlycome

intotheirowninthefuture.A goodexamplecomesfromanother

systemthePentagondevelopedtocounterieds:“Gorgonstare”al­

lowedaircrafttotakenear­continuousvideoofwholecitiesover

weeksandmonths.Theideawasthat,afteranattack,itwouldbe

possibletorunbackthetape,asitwere,toseewhentheiedhad

beenemplacedandtotracemembersoftheinsurgentgroupre­

sponsible.Inprinciple,sararchivescouldprovideananalogous

abilitytoturnbacktheclockinlightofnewdataforselectsitesall

aroundtheworld.

PayamBanazadeh,thefounderofCapella,saysthatwiththesix

satelliteshiscompanynowhasinorbitit cancheckinonanyspot

ontheplaneteverysixhours.Thecompany’splanned40­satellite

constellationisintendedtogetthatrevisittimedowntonomore

than 15 minutes—lesstimethanitwouldtakefora countryto

launcha ballisticmissile,MrBanazadehnotes.Thesatellitescan­

notoperate24/7:theirpower­hungryantennaetaketheirsuste­

nancefromsolarpanels,andtheirbatteriesarenotlargeenough

forthemtooperatecontinuouslyatnight.Buttheydoprettywell.

Thegrowthoficeye, whichiscurrentlyoperating 14 sarsatellites,

Capellaandother companiesmeans thenumber ofsatellites

availableisrisingrapidly,reducinggapsincoverage.Allthese

companieshavemilitarycustomers.

Thetimeittakestogettheinformationdownfromspaceand

intothehandsofthosewhoneeditisalsofallingquickly,asbig

datacompanieslikeAmazonWebServicespileintothemarket

andexpandthenumberofgroundstations.Infiveyearsitwillbe

possibletorequestanimage,communicatewiththesatelliteand

receivetheproductinminutes,saysJoeMorrisonofUmbra,a

CaliforniafirmwhichlauncheditsfirstsarsatellitelastJune.

“You’llsnapyourfingerandinthatsamehouryou’vegot25­centi­

metreresolutionimagery—maybe15­centimetreifit’sausgov­

ernmentnational­securityusecase.”

Umbrahopestonurturethegrowthofa downstreamindustry

thatcouldsellanalysisbasedonsardatatocivilianandgovern­

mentcustomersbymakingthosedatacheaperthantheoptical

equivalentofferedbycompanieslikePlanetandMaxar,anEarth

observationcompanybasedinColorado.It planstosellimagesco­

Putting it together

Synthetic-aperture radar (SAR)

SAR satellite

Source:TheEconomist

Satellite

track

Ground

track

Radiated

pulses

Swath

width

A

1

2

→

The satellite can see an object

at all the time as it travels

from →. The data

can be processed as if the

distance from 1 to 2 was the

aperture of a huge radar

A

1 2