Project Cyclops

This historical table has had a profound effect on the direction of SETI on planet Earth for the past quarter of a century.

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                   Project Cyclops comparison scenarios
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                       OPTICAL            INFRARED            MICROWAVE
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PARAMETER            A         B         A         B         A         B
Wavelength           1.06 um   1.06 um   10.6 um   10.6 um   3 cm      3 cm
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                                 TRANSMITTER
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Antenna Diameter    22.5 cm   22.5 cm    2.25 m    2.25 m    100 m     3 km*
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No. Of Elements      1         1         1         1         1         900
Element Diameter     22.5 cm   22.5 cm   2.25 m    2.25 m    100 m     100 m
Antenna Gain     4.4x10^11 4.4x10^11 4.4x10^11 4.4x10^11 1.1x10^8 9.8x10^10
Peak or CW Power, W  10^12     10^5      10^5      10^5      10^5      10^5
Modulation           Pulse     Pulse     Pulse     PSK       PSK       PSK
Pulse, s             10^-9     1         1         1         1         1
Energy per Bit, J    10^3      10^5      10^5      10^5      10^5      10^5
EIRP, W          4.4x10^23 4.4x10^16 4.4x10^16 4.4x10^16 1.1x10^13 9.9x10^15
Beamwidth            1"        1"        1"        1"        64"       1"
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                                   RECEIVER
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Antenna Diameter     100 m     100 m     100 m     2.25 m    100 m     3 km*
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No. Of Elements      400       400       1975      1         1         900
Element Diameter     5 m       5 m       2.25 m    2.25 m    100 m     100 m
Atmosphere Tran.     0.7       0.7       0.5       0.5       1         1
Quantum Effic.       0.4       0.1       0.2       0.2       0.9       0.9
Solar Background 1.2x10^-3     36    1.7x10^-3   6x10^-7     -----     -----
Noise Temp., K       13,600    13,600    1360      1360      20        20
RF Bandwidth         1 GHz     3 MHz     3 kHz     1 Hz      1 Hz      1 Hz
Detection Method     Photon    Photon    Sq. Law   Synch.    Synch.   Synch.
Range Limit (L.Y.)   26        24        22        41        500     450,000
State Of The Art?    ?         No        ?         No        Yes       Yes
All Weather?         No        No        No        No        Yes       Yes
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    * Array spread out to 6.4 km diameter to avoid vignetting.

    Data taken from Table 5-3, page 50, July 1973 revised edition
    (CR 114445) of the Project Cyclops design study of a system for
    detecting extraterrestrial life.  This study was prepared under
    Stanford/NASA/Ames Research Center 1971 summer faculty fellowship
    program in engineering systems design.  Note that at the time the
    Cyclops study was done, the field of "optoelectronics" (photonics) had
    not yet really begun.  Thus, what the Cyclops study called "Optical" is
    really a superset of both "near-infrared", and "infrared".  In this
    Optical SETI paper, "optical" covers the entire spectrum from ultra-
    violet to the far-infrared.  The near-infrared 1.06 um ETI transmitter
    for the Optical System A is only 22.5 cm in diameter, and is modelled
    to be putting out 1 kW pulses of 1 ns duration, with a peak power of
    one trillion watts and corresponding peak EIRP of 4.4 X 10^23 W!