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Using Pulsars For Spacecraft Navigation
Jimme Blue writes "The use of pulsars as a GPS analogue holds the promise of fixing a spacecraft's location to within 5 km, anywhere in the galaxy. While not ready for immediate use, it may be ready for use within the Solar System in the next 10-15 years. From the article: '"The principle is so simple that it will definitely have applications," said Prof Werner Becker from the Max-Planck Institute for Extraterrestrial Physics in Garching.
"These pulsars are everywhere in the Universe and their flashing is so predictable that it makes such an approach really straightforward," he told BBC News.'"
Within the solar system, visibility to a known set of pulsars shouldn't be an issue, but as you venture outside the solar system, which pulsars are visible may begin to change as pulsars don't emit in all directions. In practice, most pulsars in a given galaxy probably rotate/emit more or less in the galactic plane, so, even within a galaxy, it's probably a good reference. But that's definitely a risky method if you start moving out of the galactic plane.
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This has been in use in sci-fi since the dawn of space opera. It gained sufficient use that it was internalized to the point that it's rarely mentioned anymore, you could even say it's why most sci-fi expects a reliable knowledge of location and date even in the face of miss-folds and unplanned time travel.
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I assume you took this prior art as inspiration? (Incidentally, I also tend to recall Sagan mentioning pulsars in the first episode of Cosmos being once believed to be a form of alien navigation. Guess that's why he and Drake put them on the plaque.)
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This isn't exactly a new idea:
http://en.wikipedia.org/wiki/Pioneer_plaque#Relative_position_of_the_Sun_to_the_center_of_the_Galaxy_and_14_pulsars
Yes. I patented that plaque.
They were. A pulsar signal is a repeating pulse - a characteristic previously thought to be unique to artificially generated transmissions, perhaps a beacon of some purpose. It must have been quite a letdown when someone worked out a natural process that could generate such a signal.
How do we know a pulsar's period cannot change over millenia? I mean all sorts of things can change a pulsars period .. collision with a red dwarf for one.
Isn't it easier, and far more accurate to use the regular stars? There are billions of them .. many of which have known rotational periods, brightness variability, and proper motions that can be detected via doppler shifts and other means. The Hipparchos satellite produced a fairly accurate 3D map of the neighborhood .. that can be a good starting point. Every star has it's own spectrographic and brightness variation signature .. Sure black swan events may change a stars spectrum, variability cycle, and other things .. but there are a billions stars .. a spacecraft can navigate by tracking just a few million of them (a wide field gigapixel camera and few spectrographic telescopes, should be all it needs) .. its extremely unlikely that more than a few percent of them will change enough to cause navigational errors .. just update the star tables every 10,000 years .. normal GPS has to it that way more often with satellites.
...i.e. his final orders, quoting Peter Pan.
Are you nuts? Do you want the aliens to come destroy us in response to such an obvious act of war?
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the Voyagers (and Pioneer 10 & 11) have plaques depicting the origin solar system in relation to contemporary pulsar events and the centre of the Galaxy.
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