Pl' ..John A. (1' !\L'cfe has concluded that "the most prob<iblc cx-
pL!natll)n of till' C!CI1I1 cffl'd is millimet.er-size fluKes of iniltcrial
libl'l"atl'~l at or ll{'ur sunrise by the spacecraft" (NASA, 19(J:l, pro 1(J~}-2(n).
R<.'t\'l'CIlCl' is hCft' lIlade to Fig. ri. We note that
th\.' apparent magnitude of the sun-illuminateJ spl1ere of diameter 1 lOrn.
at 1 m. is -7. 11li~ is in general agreement with the description of
brightness given by Glenn who referred to them as looking like steady
fi refl ies.
Or-ser\'Clti 'lllS b~' Hstronauts in subsequent flights showed that
Of~('('fe'~ illtel'jlTetation is {llmost certainly correct. Astro-
naut Carp~nter in ~Iercury 7 found for example that (NASA SP-6, p. 72).
At drllm on the third orbi t as I reached for the
densitometer, I inadvertently hit the spacecraft hatch
and a cloud of particle;;, flew by the window ... T
~:oJltinued to knock on the hatch aml on other portions of
the spacecraft walls, and each time a cloud of parti cles
ca~e pagt the window. 1~e particles varied in size,
brightness, and color. Some were grey and others were
\\h1 te. TI1C 1argest were 4 to 5 times the 5 i ze of the
smaller ones. 'Jnc that 1 saw was a hal f inch long. It
was shaped like a curti cue anJ looked I ike a lathe turning.
A modification of the flknoding" technique llsed by astronaut
Carpenter to g('t the "firefly" effect was used by some f)f the C;emini
astl'onaut5 who d1 scovc!'cd that a bri lliant di splay resul ted from a
urine dump at s~mri:;l'. The crystals which formeJ near the spacecraft,
I,hell illul1lin[lt~·d by tlw SUll, looked like hrilliant stars. P"ate 22
il:ustratl's th(' eff<.'ct (1:1-(1, ~1:lgazine B, Frame 2!)).
Silllll;ll' spc:cta\~'ular l'ffC'l·t~ I'!erc o;·taincd by venting one of
till' o,,-'.'oarJ st\Jra~l' tanh~; \'iIH.'1I the sun wu-.; low. One such event is
Jesl'l'ibeJ l'~' astrolwllt Conrad (CT-S, tllpe' 21,!), J1;1ge 2) ~;pca:~ing
to tht) ~rouJlJ erel'!:
304
Pl' .. Iohn A. (l'l\l'l'f(' has ..:on(~l\lJeJ thut "the most prob(.tblc cx-
I'Llllat Il11\ of tIll' Clenn efred is llIi 11 illlcter-s i ze flUKes of ir,iJtcdal
libl'l':lt~',l at or ll('ur slIlIris(' by thl' spucecr'aft" (NASA, 19()r., pp. l'J~I-2rn).
Rl'fl'!'CIlCl' is hel't' IU;ldc.: to Fig. ri. lve notc that
tlh' apparent magnitude of the sllll-illuminateu sphere of diameter 1 mm.
at 1 m. is -7, Thi" is in general agreement with tho description of
brightness given by Glenn who referred to them as looking like steady
fireflies.
Ob"er\':lti'lllS b,' ilstronauts in subsequent flights showed that
Ofl\eefe" il,terpretation is almost certainly correct. Astro-
naut Carpenter i n ~\crcury 7 found for cxamp le that (NASA SP-6, p. 72).
At dawll on the third orbit as I reached for the
densitometer, I inadvertcntly hit the spacecraft hatch
and a cloud of particle;, flew by the window ... T
I.'olltinued to knock on the hatch anu on other portions of
the spacecraft walls, and each time a cloud of parti des
caine pa.,;t the 1~i.l\dQw. 11\e pal'tJclcs varied in size,
brightnes~. and color. Some were grey and others were
\\hite. 'n1e largest were 4 to 5 times the size of the
smaller ones. 'Jnc that 1 saw was a half inch long. It
was shaped like a curlicue and looked like a lathe turning.
1\ modificntioll of the "knocking" technique used by astronaut
C:lrpentcr to get the "firefly" effect was used hy some f)f the Cemini
astnmrluts '11\1<' di sc()vcl'cd that a bri Iliant di splay resulted from a
urine dump at ~',mri ';l'. The crystals which formed near the spacecraft.
"hell iltumillntvd hv thl.' sun, Inohed like hril1i.ant stars. V,cate 22
il:u::;tratl's th\, "rrt'ct U;!-(" ~1agazine II, Frame 2!)j.
Sillli lar spl'ctac:ular l'ffC'l't~ were o,'t;1inco by venting one of
(hlC such event is
J\':-;rribl.'J L'\' astt'un<lllt Conrad ((;'1'-:;, tapc 2fl!l. p;!ge 2)
to the ~ro\ll1d crelv:
304
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~;pca,< 1 nC