Imagine doing brain surgery by remote control.

That's just what STL engineer, Robert E. Gottfried, did over the weekend, on an ailing deep space probe.

Pioneer 5 blasted off on March 11, and it recently passed the 5 million mile distance mark on its way to the orbit of Venus.  For more than a month, the doughty probe returned an excellent stream of data thanks to its digital brain, Telebit.  This little computer allows the spacecraft to store experimental results and beam them back to Earth at regular intervals.  Thus, observers on the ground get continuous readings of the magnetic, radioactive, and micrometeoroid properties of interplanetary space.

But then some of the data Pioneer was sending back became… strange.  For instance, the spacecraft reported that its battery voltage was too low to send signals—as it was sending signals! 

How do you fix something that's twenty times as far away as the Moon?  First, you figure out what the problem is.  Luckily, Pioneer's builders (Space Technology Laboratories in Los Angeles) had the foresight to make a back-up copy of the Telebit hardware.  Gottfried poked and prodded the thing until it started giving him results that matched the ones received from Pioneer's system.  Through painstaking tracing, the culprit was found—a single faulty or damaged diode, a pinhead-sized component, one of 1500. 

The result was that there was a consistency to the flawed data that could be compensated for.  Once Gottfried knew what the problem was, he could create a program that would take data from the bad Telebit and translate it into good data.  The digital patch worked.  While we can't fix Pioneer 5, we can now translate its gibberish into useful science.  For his efforts, NASA's chief administrator, Keith Glennan, dubbed Gottfried "The Long-Armed Repairman" in a congratulatory telegram.

For the curious, Pioneer 5's cooling systems maintain its internal temperature at a balmy 50 degrees.  Not bad for being in the vastness space!  The probe is still using its lower power 5-watt transmitter, and is still being received clearly at the giant Jodrell Bank radio telescope in England.  However, the smaller "dish" in Hawaii is already having difficulty picking up the spacecraft, so it is likely that Pioneer will start using its bigger 150-watt transmitter next week.  NASA believes we will be able to communicate with the probe as far out as 50 million miles!

To give you an idea of how amazing this is, think about the stations you pick up on your AM radio.  They broadcast at around 50 thousand watts, and you can only hear them if they are relatively close (one can pick up some fairly distant stations at night, but none are more than a thousand miles or so away.)

Of course, your antenna is probably a telescoping rod or a long wire.  The dish at Jodrell Bank is 250 feet across!  Nevertheless, that it can pick up such an unprecedentedly distant and weak signal is almost miraculous.  I say "almost" because it was not luck that made it happen but good engineering and pioneering digital technology.

Quite a remarkable feat, and worthy, I think, of an article. 

Who calls a press conference at 2:00 in the morning?

And what sort of fool journalist covers a 2 A.M. press conference?

NASA and me, respectively.

Dr. Keith Glennan, NASA's administrator, admitted that it was an unorthodox time to gather scientists and reporters together, but given the unprecedented nature of the event to be discussed, it's quite understandable.  After all, never before in the history of humanity has a message been received from an artificial probe 1,000,000 miles from Earth.

Pioneer 5, the interplanetary mission launched last week, is now four times as far from the Earth as the Moon, and its 5 watt transmitter is still being picked up loud and clear.  In a dramatic flourish, just after the conference started, Dr. Glennan ordered the tracking station in Hawaii to query the spacecraft.  The plucky probe responded in a jiffy (discounting the 5-second delay since radio signals travel at the speed of light) to the delight of the audience.

One of the great advancements of Pioneer 5 is its use of digital data.  Earlier probes used analog data, faithfully transcribing experimental results as a steadily varying voltage that would be transmitted, real-time, to Earth.  Not only can digital data be easily stored so complete results can be sent back to Earth at any time, it also requires no "translation" to a language ground-side computers can understand.  This means that data can be analyzed far more rapidly.

In fact, Pioneer 5's latest space weather report on the cosmic radiation, magnetic field, and micrometeorite situation a million miles out was reduced and presented during the course of the half-hour press conference.  How's that for instant service?

Pioneer also gave an account of its own health.  NASA's week-old baby is healthy and happy: its interior remains at a balmy 63 degrees Fahrenheit, its solar-powered batteries are charging nicely, and the transmitter is strong. 

In the weeks to come, Pioneer 5 will remain on the air out to an anticipated distance of 25,000,000 miles.  This flight will challenge NASA's ability to track and hear the probe to the limits of current technology. 

And, apparently, any notions that I might have a reasonable sleeping schedule!  Not that I'm complaining—it's an amazing time to be alive.

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