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Using Pulsars As GPS For Starships
cold fjord writes with an excerpt from Science Codex: "CSIRO scientists have written software that could guide spacecraft to Alpha Centauri ... Dr George Hobbs (CSIRO) and his colleagues study pulsars — small spinning stars that deliver regular 'blips' or 'pulses' of radio waves and, sometimes, X-rays. Usually the astronomers are interested in measuring, very precisely, when the pulsar pulses arrive in the solar system. Slight deviations from the expected arrival times can give clues about the behaviour of a pulsar itself ... 'But we can also work backwards,' said Dr Hobbs. 'We can use information from pulsars to very precisely determine the position of our telescopes.' 'If the telescopes were on board a spacecraft, then we could get the position of the spacecraft.' Observations of at least four pulsars, every seven days, would be required. ... A paper (paywalled) describing in detail how the system would work has been accepted for publication by the journal Advances in Space Research."
(Here is a related story from the same source.)
My taxes paid for it!
The paper is available free from the arXiv (http://arxiv.org/abs/1307.5375)
Full speed ahead to Goat Island!
This is so 1970's...
http://en.wikipedia.org/wiki/Pioneer_plaque
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Sounds like the CSIRO have been reading 1980's era science fiction. Maybe even the chapter in the Star Trek: The Next Generation Technical Manual [http://en.wikipedia.org/wiki/Star_Trek:_The_Next_Generation_Technical_Manual] that describes this navigation technique. (3.12 Guidance and Navigation)
I'm sure that would be more interesting.
Pulsars are also where intelligent alien species of the galaxy hang out.
I'd like to congratulate Dr Hobbs and his team for inventing a navigation system for Starships. Now, I look forward to Zefram Cochrane's work on the Warp Drive getting completed!
I guess in this context "GPS" is "Galactic Positioning System."
Really? To which globe are we referring? I suppose "UPS" is taken as an acronym, but still....
The brass plaques on the Pioneer and Voyager spacecraft show the location of the Earth using a map of nearby pulsars.
This is like Karl Benz figuring out road signs.
If we currently do not have a way to travel to the stars, then what does it matter how we find our way among them?
They're using their grammar skills there.
Just add a cross hair to the "windscreen" of the space ship and point it at the damn star that you are going to pay a visit.
There will be plenty of time for fine tuning. As a matter of fact, it would be a real good recreational job for the 10.000 year long trip.
As the star got bigger you would simply change the velocity accordingly. Not such a big deal. I know, because i used to play Elite on a C64.
Since light takes quite a few light years to arrive from distant locations, you will always arrive where it was if you point your fast star ship at it and travel to that location.
...and straight on 'till morning.
Using pulsars for indicating coordinates has been done before - see for example the maps attached to the Pioneer spacecraft, which encode the location of the Sun in the galaxy:
http://en.wikipedia.org/wiki/Pioneer_plaque
Because it was the *software* holding us back!
Pulsar Signals Could Provide Galactic GPS
How a Pulsar Gets Its Spin
Using Pulsars For Spacecraft Navigation
Are the pulses from pulsars visible from all directions, or just from the plane of rotation? If you move far enough, will some disappear and others appear?
There is nothing so silly as other peoples traditions, and nothing so sacred as our own.
I guess If you replace the word Global with Galactic then it would make sense.
What happens if we have a starquake on one of the pulsars thus shifting its rotational speed by a microsecond? Will our starship navigation put us off by a few parsecs?
Seven days to get a read on current position? Still better than NeverLost :)
NASA is developing an experiment called NICER/SEXTANT that will include a demonstration of this technique using x-ray pulsars. It will go on the ISS and use the pulsars to track the position of the ISS. Of course we have much better ways of doing that already but it could be an important demonstration for future probes to the outer solar system.
http://www.nasa.gov/topics/universe/features/zombie-stars.html
My dad had some "Best of" Analog and Astounding collections dating back to the mid-'50s. Those omnibus editions got me hooked on sci-fi at a very young age.
I remember reading more than one story out of those where using pulsars to determine a ship's current position was a key plot point. According to Wikipedia, the first pulsar was discovered in 1967. Given the intense interest that most sci-fi writers and readers had in astronomy, I would be very surprised if that information wasn't common knowledge within the community almost immediately.
The idea of using x-ray pulsars for navigation has been around for at least 10 years, probably longer. Wikipedia [http://en.wikipedia.org/wiki/X-ray_pulsar-based_navigation ] has some papers from MIT on it's stub entry.
Here's a presentation/paper from Naval Research Lab (NRL) in 2006 that gives you a general approach.
http://tycho.usno.navy.mil/IAU31/sheikh.pdf
And while it's nice to see demonstrations of software that show that it's doable, I don't think that's really the big challenge. The real challenge, and the one generally sort of hand-waved away, is that nobody has built a sufficiently useful X-ray telescope/detector that can be put on a spacecraft.
Sure folks say "look at Chandra which had 10s of tonnes of telescope, and modern X-ray telescopes in the lab at 10s of kilos", but it's a long long way from "lab bench" to "flying on a spacecraft", and not just because of the natural conservatism of spacecraft folks. Things on the bench have someone standing there to turn a knob, or tweak it to make it work today, etc. In space, it has to be really and truly maintenance free for years and years (particularly for deep space). When you come back and say "we've got a 1 kg X-ray telescope that has operated continuously with no manual intervention for 1 year", then I'll say "Yep, XNAV is here"
If you're going slower than the speed of light
The paper directly addresses this is useful for travel within the solar system or even on a trip to Mars, routes that we've already sent crafts through before. There are additional experiments that would benefit from better positioning of satellites within the solar system.
Pulsars: The Nav Beacon's of the Universe. Been that way since they were discovered - just like VOR beacons for Airports
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Working this out would be like people 3000 or so years ago trying to make some kinds of meaningful decisions about 21st century technology.
File under 'M' for 'Manic ranting'
I seem to remember an episode of Star Trek where they ended up in the armpit of space such that they couldn't get a Federation navigation signal. They used pulsar triangulation to get a fix on their location.
Now, of course, implementation of this theory in the 21st century is a different matter!
Gamingmuseum.com: Give your 3D accelerator a rest.
Pulsars and Cepheid Variables have been used as cosmic lighthouses for decades. These techniques are what have allowed astronomers to determine our relative position in the Universe, the structure of the Virgo cluster, and the general structure of the visible universe in general.
That would be great if pulsars were fixed points in space. But the universe is expanding, and so their position changes even for objects in our own solar system.
They're using their grammar skills there.
"Notch," the developer behind the famous Minecraft game, also ostensibly proposed pulsars as navigation beacons for his now-defunct game "0x10c." He used (generated) data collection from a pulsar as part of a series of puzzles related to PR for the game.
First off, the pulsars being discussed, including the example selection used in the paper, are within our own galaxy and not that far away, so the expansion of the universe is not relevant (at least on any timescale that our solar system is still around). The methods are also rather insensitive to small movements of the pulsars, nonetheless, one of the prerequisites is that the pulsar be observed for a few years prior to the trip to establish timing and timing error. If you really insisted on using one with an obnoxious speed for a very long period, you could account for it, especially since the pulsars have to be monitored form Earth during the process too. But even if the pulsars were traveling some decent fraction of the speed of light, for short trips like to Mars, it wouldn't cause problems from their change in position.
Should be CPS for celestial positioning system, not GPS - it'll be a wee bit larger than global...
I thought that pulsars emitted a beam of energy that was very narrow in angular size and located on a specific rotation axis.
What if you travel off the beam's axis while traveling large distances between astronomical objects?