Oncethere,itwouldfeeditsdatato
theseismometer,whoseantenna
wouldtransmitthereadingsbackto
Earth.They’dbestoredonreelsof
magnetictapeforanalysis.
O’Brien,Avrilandtheirthreechil-
drenmovedbacktoSydneyin1968,
sohemadearrangementstohavethe
tapesshippedtohim.
OnthemorninginlateJuly 1969
whentheApollo 11 LunarMod-
ulealightedonthemoon,O’Brien
vividly remembers the moment
Aldrinsaidthemodulewas“kicking
upsomedust”asitcameintoland,
aswellasArmstrong’sobservation
thatthesurfacewas“almostlikea
powder”.Witha spikeofexcitement,
O’BrienrealisedhisDDE might very
wellproveitsworth.
THE SEISMOMETER overheated
shortlyafterApollo 11 leftthemoon.
ButtheDDEsoldieredonandquick-
lyrevealedthemischiefdustcould
make.AstheLunarModuletook
off,twoofthedetector’sthreesolar
cellsregisteredasuddendropin
output,oneofthemby 18 percent.
Thiswasaccompaniedbya spikein
temperature.ToO’Brien,therewas
onlyoneexplanation:theDDEhad
beenblanketedindust,which,like
blackoutblinds,keptlightoutand
heatin.Itseemedobvioustohim
thattheseismometerhadmetthe
samefate.
IfNASAhopedtokeepitsmoon-
based instruments working on future
Apollomissions,O’Brienconcluded,
itwouldneedtostudythematterof
dust-sprayingthoroughly.ThatAu-
gust,hewroteproudlytoanAus-
traliancolleaguethat“theDDEmay
reallyhaveearneditstrip!”Buthis
Americancounterpartswerenotso
enthused.Theseismometerstopped
acceptingcommandsfrommission
control,andthewholeexperiment–
DDEincluded– wasshutdownafter
21 days.
NASA’spreliminarysciencere-
portonApollo 11 rejectedO’Brien’s
explanationfortheDDEreadings,
blamingthesolarcells’unexpected-
lylowoutputoncalibrationerrors.
O’Briensayshe“stronglydisagreed”
withthefindingsandtriedtoargue
hiscaseintheJournalofAtmospheric
Physics, usingoneofAustralia’sfirst
supercomputers,SILLIAC,tocrunch
andplotthedataonendlessribbons
ofpaper.Butthearticlewasbarely
citedbyresearchersinthedecades
thatfollowed.
O’Brienwasforcedtoadmitdefeat
inroundoneofthemoondustwars.
Hechangedcareers,becomingthe
firstheadoftheEnvironmentalPro-
tectionAuthorityofWesternAustral-
ia.ThepositionwasbasedinPerth,
andwhenAvrilmadethetripfrom
Sydney,shebroughtthekidsand
the 172 reelsofDDEdatawithher.
O’Brienaskeda colleagueata local
universitytoputthetapesinstorage.
Andso,for40-odd years, that’s where
they stayed.115
The Moondust Diaries