12 AUSTRALIAN SKY & TELESCOPE April 2019

Spinning

Several of the earliest satellites spun to stabilise their

orientations. Among them were NASA’s Orbiting Solar

Observatoriesseriesofsatellites(OSO-1toOSO-8)inthe

1960sand1970s.Theexactdesignvariedamongmodels,

buteachhada‘sail’sectionthatalwayspointedtowardthe

Sunanda‘wheel’partthatswivelledfullcircleevery2–

seconds. Both sections carried instruments, but the larger,

morecomplexoneswerehousedinthestationarysailpartof

thetelescope—afterall,themaingoalwastostareatafixed

target, the Sun. LEAH TISCIONE /

S&T

To capture our dynamic universe in all its

glory, sometimes our telescopes need to

show a little dynamism themselves.

WHEN ASKED TO THINKof a space telescope, most people

willimmediatelypictureHubblestaringmotionlessintothe

distance.Whattheylikelywon’tpictureisaspacecrafttwirling

andwrithingaroundtheskylikeaStar WarsTIEfighterafter

afatalshotfromtheRebelAlliance.Hubbleandmanyother

spacetelescopes—andamateurastronomers,forthatmatter

—collectimagesofthecosmosbyremainingasstillaspossible

foraslongaspossibletocollectasmuchlightaspossible.But

asurprisingnumberofspaceprobesoptforthedisabledTIE

fighterstrategy—albeitinafarmorecontrolledway.

Spinning