Project Cyclops
The approach NASA devised for SETI was to develop a framework with the present understanding of the universe, and then use that as the basis for increasing the probability of discovering extraterrestrials.
The order-of-magnitude uncertainty in the average distance between communicative civilizations in the galaxy strongly argues for an expandable search system.
Again, this is because greater absolute frequency stability is possible there, the Doppler rates are lower, beamwidths are broader for a given gain, and collecting area is cheaper than at the high end of the window.
Nature has provided us with a rather narrow quiet band in this best part of the spectrum that seems especially marked for interstellar contact.
It is technologically feasible today to build phased antenna arrays operable in the 1- to 3 GHz region with total collecting areas of 100 or more square kilometers.
Beamed signals may be radiated at relatively low powers by communicative races to as many as a thousand nearby likely stars and for very long times.
Long range beacons, intended to be detectable at any of the million or so likely stars within 1000 light-years, will probably be omnidirectional and very high powered (
The efficient detection of beacons involves searching in the frequency domain with very high resolution (1 Hz or less).
One of the major contributions of the Cyclops study is a data processing method that permits a 100 MHz frequency band to be searched simultaneously with a resolution of 0.1 Hz.
If our conclusion as to the appropriateness of this band is correct, the problem posed by the frequency dimension of the search can be considered solved.
The cost of a system capable of making an effective search, using the techniques we have considered, is on the order of 6 to 10 billion dollars, and this sum would be spent over a period of 10 to 15 years.
The search for extraterrestrial intelligent life is a legitimate scientific undertaking and should be included as part of a comprehensive and balanced space program.
We believe that the exploration of the Solar System was and is a proper initial step in the space program but should not be considered its only ultimate goal.
The quest for other intelligent life fires the popular imagination and might receive support from those critics who now question the value of landings on "dead" planets and moons.
A great deal more study of the problem and of the optimum system design should precede the commitment to fund the search program.
Out of such studies would undoubtedly emerge a system with greater a capability-to-cost ratio than the first Cyclops design we have proposed.
John Billingham, who co-chaired the Cyclops team, wrote a dedication to Bernard M. Oliver, which appears in the new edition, along with introductory remarks by SETI League president Richard Factor and executive director H. Paul Shuch.
