Targeted Search: Project Phoenix
The second major way of looking is to target, a priori to pick out the directions
where you think there is a high probability of having a signal. This is what
Project Phoenix, the project that I direct, is about.
Project Phoenix is a systematic microwave search
from the frequencies between 1.2 and 3 gigahertz. We target a thousand nearby
stars; we look at the nearest 100 stars independent of their spectral type; and
we look at all known exoplanetary systems. Then we select solar-type stars,
preferentially those that are a few billion years old and that do not have any
companions that might disrupt planetary orbits.
We are also following up on 11 events that the
META search published a few years ago on the possibility that these might turn
out to be extraterrestrial transmitters which were below the detection
threshold. Interstellar stimulation have may amplified them briefly so that
they could be seen by the META system, but then they faded away and were never
seen again. So we are going back to look with much higher sensitivity at these
targets and to look several times.
The name Phoenix alludes to the project as rising
from the ashes of congressional termination. Unlike the movie Contact, we do not wear headphones. But we do actually plan for success and
there is a real bottle ofchampagne in the observer’s icebox at Arecibo.
The signal processing that we do is based on
full-custom digital signal processing gear. We cover 20 megahertz of dual
polarization bandwidth. With 1 hertz resolution we have 56 million channels
that we analyze every second. It is full-custom. It is a pain and we will never
do it that way again.
We can package the equipment in a trailer so that
we can take it to large telescopes around the world. It is the silicon
intelligence of the system that does most of the work, although at first it
takes a lot of people to get the system up and running. Then it takes fewer
people as the system learns to do the job.
Eventually, you have a system that runs itself
and runs the telescope. Of course, now that we have it all working, we are
about to build a new system that has five times the bandwidth, has higher
resolution, and should be coming on line with the telescope by the Fall of
2000.
There are some things that are unique about
Project Phoenix. As a NASA program, when we first deployed to Arecibo
Observatory in 1992, we learned a very important lesson: one telescope is not
enough. In an RFI (radio frequency interference) environment, which is
temporally varying, you cannot do an efficient search program with one
telescope.
Contributed by: Dr. Jill Tarter and Jim Miller
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