Project Cyclops, A Design... - Department of Earth and Planetary ...

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(/1 i .E cn _J (E 10 3 10 I01 I I01 i i irrfll i i r i IITII i i r i IIIIF I ii X,icm _ < / ASSUM PTIONS 10 2 10 3 10 4 10 5 CLEAR APERTURE DIAMETER, m a large number of the stars will be giants and supergiants at great distances in the galactic plane, where interstellar absorption dims their optical brightness but not their radio brightness. Thus, it would not be at all surprising to be able to detect over a million stars with a I 0-km aperture or 30,000 with a 3-km aperture Cyclops system, with 1 rain of integration time. Most of the detectable stars will be giants and supergiants. Although these are in fact less numerous than main sequence stars, their large size makes them visible to 10 to I00 times as great a range. If we assume that the radiation of main sequence stars is enhanced over their black-body radiation in the same ratio as for the quiet sun, their range limit will be given by .c ol i G _ IO 3 t0 2 rO I Figure R-1. Radio visibility of the quiet sun. I_........ , ........ ,y/j/ ...... , c6 j hkh'/ T:I6 _K +TsK Y ///// '°22z ///J ASSUMPTIONS j ,x/y,,,,,, ........ ::o,::,,,, ...... io_ to2 io3 io4 io5 CLEAR APERTURE DIAMETER, m Figure R-2. Radio visibility of the active sun. VISIBILITY OF OTHER STARS We can get a crude estimate of the number of stars detectable by Cyclops by assuming that a star will be detectable if its apparent magnitude is equal to that of the Sun at the range limit. The apparent magnitude of the Sun at 10 pcs is about 5; at 100 pcs it would be a magnitude 10 star. From Table R-I we see that for a lO-km array atX = 3 cm, the range limit for the Sun is in fact about 100 pcs (326 light-years). If all magnitude 10 stars were detectable, the number would be about 350,000. For a 3-km array the number would drop to about 10,000 stars. The above numbers are pessimistic for two reasons. First, as stellar temperature drops, the radiation falls faster in the visible than at longer wavelengths because the quantum cutoff shifts. The majority of stars are cooler than the Sun, and thus would be relatively more detectable at radio than at optical wavelengths. Second, 242 tl/2 R, = R o T, d_.2, \to do (R5) Using the data for T, and d, given in Allen for main sequence stars of various spectral classes, we find the range and ratios given in Table R-2. TABLE R-2 Type T,/T o a,/d ° R,/R° fR,/Ro)3 05 5.83 17.78 42.9 79,100 BO 3.50 7.58 14.18 2,850 B5 2.25 3.98 5.97 213 AO 1.62 2.63 3.35 37.5 A5 1.35 1.78 2.07 8.85 FO 1.20 1.35 1.48 3.23 F5 1.08 1.20 1.25 1.94 GO 1.02 1.05 1.06 I. 16 G5 0.90 0.93 0.88 0.687 KO 0.78 0.85 0.75 0.423 K5 0.667 0.74 0.604 0.220 MO 0.55 0.63 0.467 0.102 M5 0.433 0.316 0.208 0.009 Figure R-3 was plotted using the value of R o = 190 light-years given in Table R-I for _, = i0 cm and the values of R,/R o in Table R-2. The volume of space over which stars will be detectable is V = -- 3 Re3 (R6)
io 3 - l rlrllll I I I ]l+,ll_ I _f, I l_rl_JTJ _ TABLE R-3 ;t = 3.16 cm ;t = 10 cm _>, 102 i ..E o+ d _ IOI _! /// - / / F// ,/ /_///_ _/_/ASSUMPTIONS i ./////// o/ ×: _oc_ F./ " /]< //// -- +: _o. _ -/" "','// /M" B _./ / .//// /.+" ./ o B = 10 HZ E / .//I///., //// _//// r : 60 sec i/.,/.
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(NASA-CR- 11_5) PROJECT CYCLOPS: A
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CR 114445 Available to the public A
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At this very minute, with almost ab
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ACKNOWLEDGMENTS The Cyclops study w
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COMMUNICATION BY ELECTROMAGNETIC WA
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APPENDIX A - Astronomical Data ....
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t _ 2
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of the living beings evolved by the
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Figure2-1. M3I,the great galaxy in
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self.Thus,wecaninterpretFigure2-2as
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magnitude (low brightness) end, the
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Red Giant. The transition from main
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tion, as the central part of the cl
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TABLE 2-4 SELECTED NEARBY STARS WIT
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tideraisingforcesasr--_ where ,v =
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3. Is it possible that living syste
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lawsof natural selection, more like
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starsthroughout the Galaxyhave also
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if the longevity of that life is ty
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The imaginative reader will have no
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Lookingfar ahead,supposewe aresucce
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usuallyterritorial expansion by the
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IOO IO 1 [ [ J [ J I J i [ i I i I
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order with what Morrison has descri
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The quantity gtPt is often called t
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which might result from synchronous
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1. Wewillnothavenough resolving pow
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normalwith the meanat o x/--2. When
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Chapter11 in analyzingthe dataproce
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Therangelimitisthenfoundbyequating_
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TABLE 5-3 PARAMETER Wavelength Tran
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angeanddirectlyasthesquareof antenn
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"_ i i i i i p = STELLAR DENSITY AT
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I-- g u. O >- I--- .d tit (]O 0 0.
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andwidth that will still give near
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acquisitionphasefor otherraces.Supp
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1. They would transmit continuously
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and ¢-Ceti. No signals were detect
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vz .i g)mo PAGE NOr Ir[[,MZ 7. THE
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The price of incomplete sky coverag
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modest size.A largedatabaseontapeor
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THEAUXILIARYOPTICALSYSTEM Althoughn
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edetectedat 20,000light-years byCyc
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feeds must correct for spherical ab
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side of the dish and shade on the o
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TABLE 8-1 UNADJUSTED UNIT COST DATA
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7. Using huge specially designed ji
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9. THE RECEIVER SYSTEM The receiver
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whereP is the radiated power. Divid
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SHADOWED AREA SHADOWED AREA // // /
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Corrugatedhornssupportingbalancedhy
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o 50 ----- - _ T i 20 _,o 5 ,,,5 09
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TABLk ?- I A COMPARISON OF VARIOUS
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CENTRAL POINT STATION LSB LINE FREQ
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A02 .... + No (25) (i C 1 where No
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COAXIAL LINE DIRECTIONALCOUPLER FRE
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DeJager, J.T.:IEEETrans.onMicrowave
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pR_ING PA6E BLANK HOT FILMF_ 10. TR
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o-------------o_ _ o o o o ing of t
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addedto theother IF channel. The tw
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INPUT MHZ _PF 500 MHZ i : 575 T1 92
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azimuth _) has a delay (2a/c)sin 0
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stripline. For 2 _< k _< 6, appropr
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mation are common to all antennas i
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A cable pair costs about 20 cents/m
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11. SIGNAL PROCESSING The Cyclops s
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1.0 T t t I I r .9 -8 asynchronousl
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collimated coherent light. A simple
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power of the film and associated op
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samples simultaneously onto the sam
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outputs is assumed. COMPOSITE SIGNA
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SPECTRUM I n LINES M n LINES U SPEC
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signal andyet have a tolerable fals
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i --_- i i i i large values of n. T
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plottedin Figure11-15for various va
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All the1Fsignalswillarrivein phasei
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x:(1 +x) x 2 - _ -- (53) If we wish
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3's = unitcostof signal planelectro
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where0ma x is the maximum value of
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Roughestimates of the costs of buil
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12. CYCLOPS AS A BEACON Although th
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13. SEARCH STRATEGY The high direct
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distantgalaxies (oraninertialrefere
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wouldfollowtheuppermost linein Figu
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persquaredegreeof fieldwouldberequi
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starsfrom/'18 to G5 could support a
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14. CYCLOPS AS A RESEARCH TOOL Thro
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Only a few such galaxies have been
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15. CONCLUSIONS AND RECOMMENDATIONS
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perhapsdecadesand possiblycenturies
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APPENDIX A ASTRONOMICAL DATA DISTAN
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PLANETARY Planet ORBITS Semimajor S
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APPENDIX B SUPERCIVILIZATIONS AND C
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ABIOLOGICAL CIVILIZATIONS Many writ
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182
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tqOT APPENDIX C OPTIMUM DETECTION A
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to rmsnoise.Wenotethatthematchedfil
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APPENDIX D SQUARE LAW DETECTION THE
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If the output filter is very wide c
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Page 209 and 210: APPENDIXE RESPONSE OF A GAUSSIAN FI
Page 211 and 212: APPENDIXF BASE STRUCTURES AZ-EL BAS
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Page 219 and 220: PAGE BLANK NOT APPENDIX H POLARIZAT
Page 221 and 222: APPENDIX I CASSEGRAINIAN GEOMETRY C
Page 223 and 224: APPENDIXJ PHASINGOFTHE LOCALOSCILLA
Page 225 and 226: APPENDIXK EFFECTOF DISPERSION IN CO
Page 227 and 228: APPENDIX L TUNNEL AND CABLE LENGTHS
Page 229 and 230: where r = "Ym/'rs- If we let o-_--o
Page 231 and 232: L-4 we see that the length of IF ca
Page 233 and 234: APPENDIX M PHASING AND TIME DELAY A
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Page 239 and 240: APPENDIX N SYSTEM CALIBRATION The p
Page 241 and 242: APPENDIXO THE OPTICAL SPECTRUM ANAL
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Page 245 and 246: APPENDIX P LUMPED CONSTANT DELAY LI
Page 247 and 248: Thevalueofthefinalcoilonthelineis =
Page 249 and 250: APPENDIXQ CURVES OF DETECTION STATI
Page 251 and 252: I I I I LE :E oo
Page 253: APPENDIX R RADIO VISIBILITY OF NORM
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