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

More documents

Recommendations

Info

kt foo N --T j ° I_(_)+K(-_)]__I° k T (El 2) Thus the ratio of the peak output pulse power to the noise power is S P --= N 2x/_- kTom 2 (El3) Now om 2 = o + 6o2/o 3 and has a minimum when O = (3)1/4_ 1/2 (El4) At this value, m 2 = 4/3 so we find from (El3) = P P _ °Pt kT(_,/2) = kTk3.3.3.3._//23/2 _,/2 ) (El5) The factor 23/2 /3 - 33/4 - 1.24... (El6) degrades the output signal-to-noise ratio to the value that would exist with the same filter, and a nonsweeping signal of 0.937 dB less power. 198
APPENDIXF BASE STRUCTURES AZ-EL BASE STRUCTURES The conventional az-el mount affords maximum sky coverage, but this coverage is expensive due to increased structural weight and expensive gearing and/or track and wheel assemblies. Elevation rotation is generally provided by gear or chain drives and generally requires counterweighting of the dish to locate the dish center of gravity on the elevation axis. The gearing on the elevation drive must provide the necessary resistance to wind torques. If the basic dish weight (including backup structure) is W, then a weight penalty of roughly 0.3W may be incurred in positioning of the center of gravity. Dish attachments to the base structure are either near the center (king-post design) or near the dish extremity (Manchester mount). Azimuth positioning and dish support are provided either by a hydrostatic bearing coupled with a gear drive or wheel and track drive, or solely by wheel and track support. Typical support configurations are shown in Figure F-l. MODIFIED AZ-EL BASE STRUCTURE Available cost figures for contemporary designs indicate that the base structure, which includes all drive elements, is a significant fraction of the cost of the telescope structure. Here we consider a support structure that lends itself to mass production fabrication. Threepoint support of the dish is provided, and the need for counterweighting of the dish is eliminated. The assembly uses a single piston for elevation control and a wheel and track arrangement for azimuth positioning. The use of the piston for elevation control eliminates the need for rigid support on the backup structure to support the bull gear segment required on conventional designs. This rigid support structure and the bull gear segment are comparatively expensive items. A novel feature of the base structure is the use of a central bearing to absorb all side loads; the wheel and track arrangement need only provide vertical support and therefore does not require close control of the track radius. BEARING FOR SUPPORT GEAR DRIVE FOR AZIMUTH WHEEL AND TRACK FOR SUPPORT AND ROTATION LARGE RADIUS WHEEL AND TRACK ffOR SUPPORT AND ROTATION CENTRAL BEARING POST OPTION Figure F-I. Typical configurations. Preliminary Sizing Figure F-2 shows two views (to scale) of the proposed mount designed for a I00 foot dish with a maximum zenith angle of 65 °. A preliminary calculation has been made to obtain a weight estimate assuming the dimension L_ '= 30 ft. With L_ and 0 given, the maximum piston extension p is computed to be 42 ft, which implies that a piston casing of about 45 ft is required. Since the piston casing sits vertically when the piston is fully collapsed (dish looking at zenith), the total height of the base structure h must be at least 45 ft. The height (and eventually the weight) depends strongly on the desired angle 0. Once h is found, the lengths of the truss members can be easily determined by simple geometry. 199
Page 1 and 2:
(NASA-CR- 11_5) PROJECT CYCLOPS: A
Page 3 and 4:
CR 114445 Available to the public A
Page 6 and 7:
At this very minute, with almost ab
Page 8 and 9:
ACKNOWLEDGMENTS The Cyclops study w
Page 10 and 11:
COMMUNICATION BY ELECTROMAGNETIC WA
Page 12 and 13:
APPENDIX A - Astronomical Data ....
Page 14 and 15:
t _ 2
Page 16 and 17:
of the living beings evolved by the
Page 18 and 19:
Figure2-1. M3I,the great galaxy in
Page 20 and 21:
self.Thus,wecaninterpretFigure2-2as
Page 22 and 23:
magnitude (low brightness) end, the
Page 24 and 25:
Red Giant. The transition from main
Page 26 and 27:
tion, as the central part of the cl
Page 28 and 29:
TABLE 2-4 SELECTED NEARBY STARS WIT
Page 30 and 31:
tideraisingforcesasr--_ where ,v =
Page 32 and 33:
3. Is it possible that living syste
Page 34 and 35:
lawsof natural selection, more like
Page 36 and 37:
starsthroughout the Galaxyhave also
Page 38 and 39:
if the longevity of that life is ty
Page 40 and 41:
The imaginative reader will have no
Page 42 and 43:
Lookingfar ahead,supposewe aresucce
Page 44 and 45:
usuallyterritorial expansion by the
Page 46 and 47:
IOO IO 1 [ [ J [ J I J i [ i I i I
Page 48 and 49:
order with what Morrison has descri
Page 50 and 51:
The quantity gtPt is often called t
Page 52 and 53:
which might result from synchronous
Page 54 and 55:
1. Wewillnothavenough resolving pow
Page 56 and 57:
normalwith the meanat o x/--2. When
Page 58 and 59:
Chapter11 in analyzingthe dataproce
Page 60 and 61:
Therangelimitisthenfoundbyequating_
Page 62 and 63:
TABLE 5-3 PARAMETER Wavelength Tran
Page 64 and 65:
angeanddirectlyasthesquareof antenn
Page 66 and 67:
"_ i i i i i p = STELLAR DENSITY AT
Page 68 and 69:
I-- g u. O >- I--- .d tit (]O 0 0.
Page 70 and 71:
andwidth that will still give near
Page 72 and 73:
acquisitionphasefor otherraces.Supp
Page 74 and 75:
1. They would transmit continuously
Page 76 and 77:
and ¢-Ceti. No signals were detect
Page 79 and 80:
vz .i g)mo PAGE NOr Ir[[,MZ 7. THE
Page 81 and 82:
The price of incomplete sky coverag
Page 83 and 84:
modest size.A largedatabaseontapeor
Page 85 and 86:
THEAUXILIARYOPTICALSYSTEM Althoughn
Page 88 and 89:
edetectedat 20,000light-years byCyc
Page 90 and 91:
feeds must correct for spherical ab
Page 92 and 93:
side of the dish and shade on the o
Page 94 and 95:
TABLE 8-1 UNADJUSTED UNIT COST DATA
Page 96 and 97:
7. Using huge specially designed ji
Page 99 and 100:
9. THE RECEIVER SYSTEM The receiver
Page 101 and 102:
whereP is the radiated power. Divid
Page 103 and 104:
SHADOWED AREA SHADOWED AREA // // /
Page 105 and 106:
Corrugatedhornssupportingbalancedhy
Page 107 and 108:
o 50 ----- - _ T i 20 _,o 5 ,,,5 09
Page 109 and 110:
TABLk ?- I A COMPARISON OF VARIOUS
Page 111 and 112:
CENTRAL POINT STATION LSB LINE FREQ
Page 113 and 114:
A02 .... + No (25) (i C 1 where No
Page 115 and 116:
COAXIAL LINE DIRECTIONALCOUPLER FRE
Page 117 and 118:
DeJager, J.T.:IEEETrans.onMicrowave
Page 119 and 120:
pR_ING PA6E BLANK HOT FILMF_ 10. TR
Page 121 and 122:
o-------------o_ _ o o o o ing of t
Page 123 and 124:
addedto theother IF channel. The tw
Page 125 and 126:
INPUT MHZ _PF 500 MHZ i : 575 T1 92
Page 127 and 128:
azimuth _) has a delay (2a/c)sin 0
Page 129 and 130:
stripline. For 2 _< k _< 6, appropr
Page 131 and 132:
mation are common to all antennas i
Page 133 and 134:
A cable pair costs about 20 cents/m
Page 135 and 136:
11. SIGNAL PROCESSING The Cyclops s
Page 137 and 138:
1.0 T t t I I r .9 -8 asynchronousl
Page 139 and 140:
collimated coherent light. A simple
Page 141 and 142:
power of the film and associated op
Page 143 and 144:
samples simultaneously onto the sam
Page 145 and 146:
outputs is assumed. COMPOSITE SIGNA
Page 147 and 148:
SPECTRUM I n LINES M n LINES U SPEC
Page 149 and 150:
signal andyet have a tolerable fals
Page 151 and 152:
i --_- i i i i large values of n. T
Page 153 and 154:
plottedin Figure11-15for various va
Page 155 and 156:
All the1Fsignalswillarrivein phasei
Page 157 and 158:
x:(1 +x) x 2 - _ -- (53) If we wish
Page 159 and 160: 3's = unitcostof signal planelectro
Page 161 and 162: where0ma x is the maximum value of
Page 163 and 164: Roughestimates of the costs of buil
Page 165 and 166: 12. CYCLOPS AS A BEACON Although th
Page 167 and 168: 13. SEARCH STRATEGY The high direct
Page 169 and 170: distantgalaxies (oraninertialrefere
Page 171 and 172: wouldfollowtheuppermost linein Figu
Page 173 and 174: persquaredegreeof fieldwouldberequi
Page 175 and 176: starsfrom/'18 to G5 could support a
Page 177 and 178: 14. CYCLOPS AS A RESEARCH TOOL Thro
Page 179 and 180: Only a few such galaxies have been
Page 181 and 182: 15. CONCLUSIONS AND RECOMMENDATIONS
Page 183 and 184: perhapsdecadesand possiblycenturies
Page 185 and 186: APPENDIX A ASTRONOMICAL DATA DISTAN
Page 187 and 188: PLANETARY Planet ORBITS Semimajor S
Page 189 and 190: APPENDIX B SUPERCIVILIZATIONS AND C
Page 191 and 192: ABIOLOGICAL CIVILIZATIONS Many writ
Page 193 and 194: 182
Page 195 and 196: tqOT APPENDIX C OPTIMUM DETECTION A
Page 197 and 198: to rmsnoise.Wenotethatthematchedfil
Page 199 and 200: APPENDIX D SQUARE LAW DETECTION THE
Page 201 and 202: If the output filter is very wide c
Page 203 and 204: if B/2 > T we can start instead wit
Page 205 and 206: Let us now introduce the normalized
Page 207 and 208: where h-- = expectation count of si
Page 209: APPENDIXE RESPONSE OF A GAUSSIAN FI
Page 213 and 214: ack,it shouldnotbenecessary to prov
Page 215 and 216: 204
Page 217 and 218: 206 i
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
Page 235 and 236: andobtain V = 2 (Ps [! + _(Ar)] +Pn
Page 237 and 238: L" D 226
Page 239 and 240: APPENDIX N SYSTEM CALIBRATION The p
Page 241 and 242: APPENDIXO THE OPTICAL SPECTRUM ANAL
Page 243 and 244: 232
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 and 254: APPENDIX R RADIO VISIBILITY OF NORM
Page 255: io 3 - l rlrllll I I I ]l+,ll_ I _f
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?