Jill Tarter

Who would have thought I’d miss (really be lonely for) a spacecraft? Weird. I feel like Linus when Lucy grabs his blanket.

The Phoenix Project, for which I am now observing at Arecibo Observatory in Puerto Rico, and simultaneously observing with the Lovell Telescope at Jodrell Bank Observatory in England, has been unable to detect the Pioneer 10 spacecraft. For the past five years we have been relying on this ancient spacecraft to verify that all our hardware and software at all our observing sites are working A-OK. For many other reasons, I am sure that the systems are in fact working perfectly—it’s just nice to have a security blanket!

We’re using these two large telescopes (in Puerto Rico and the U.K.) to search for radio signals that may have been broadcast in our direction (unintentionally or deliberately) by some other technological civilization. If they are there, they are coming from far away, so we’re looking for faint signals. Thus we set our detection thresholds very close to the noise limit in our systems. Not surprisingly, we hear a lot of noise and also radio frequency interference (RFI) from our own terrestrial and orbital technologies (Think: cell phones and GPS satellites). But noise is noise. It’s hard to be sure you’ve got the “right” noise. We’d still hear noise even if there were some subtle, silent failure in our equipment. So, every observing day since Phoenix went on the air back in 1995, we have pointed our telescopes at the very distant Pioneer 10 spacecraft in order to detect its faint carrier signal—by finding that signal, we know all is well and that we’ve got a chance of finding a signal from E.T.

Twice before this observing run we couldn’t find it; once a computer clock had mysteriously gained a few seconds of time, and on another occasion, someone had kicked a plug loose from the back of one of our equipment racks. Pioneer 10 saved the day. Now it’s gone.

This time we don’t really think there’s anything wrong with our equipment, instead we think the spacecraft is pointing in the wrong direction. As the Earth orbits around the sun, Pioneer 10 needs to be told to reposition its high-gain transmitting antenna so that its signals reach the place where the Earth is today, and not where it was six months ago. The spacecraft is old and more than 7 billion miles away. It was never intended to be operational for this long (28 years), and its power supply (and everything else) should have quit long ago. This little spacecraft that just keeps on running may have finally packed it in. Or perhaps the alignment command sent from NASA’s Deep Space Network last July failed to reposition Pioneer 10’s high-gain antenna. NASA couldn’t find Pioneer 10 in September, and now neither can we, even though the Arecibo telescope is about 15 times more sensitive.

Yesterday we sat around and dreamed up clever things to try when the spacecraft was once again in view of Arecibo (around 3 a.m, local time). We were hoping the signal was just fainter than we’d expected, or maybe the signal was changing rapidly because something had caused P10 to start spinning, or maybe … ? None of our tricks worked. We’ll keep trying at the right time again tonight, and the night after that, and we’ll also keep testing all our own equipment. Nope, no plugs have been kicked loose—we’ve already looked. Of course, we’ll know for sure that everything’s working if we detect an extraterrestrial signal—wouldn’t that be great, and grand, and wonderful?! The champagne is on ice, right next to the control room.

For now, we’ll have to abandon our training wheels and our security blanket and march ahead with our now mature, and thoroughly tested, observing system. Security blankets are so reassuring, but eventually it is time to move forward as a confident adult.

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