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Dead Stars To Guide Spacecraft

Spacecraft could one day navigate through the cosmos using a particular type of dead star as a kind of GPS.

German scientists are developing a technique that allows for very precise positioning anywhere in space by picking up X-ray signals from pulsars.

These dense, burnt-out stars rotate rapidly, sweeping their emission across the cosmos at rates that are so stable they rival atomic clock performance.

This timing property is perfect for interstellar navigation, says the team.

If a spacecraft carried the means to detect the pulses, it could compare their arrival times with those predicted at a reference location. This would enable the craft to determine its position to an accuracy of just five kilometres anywhere in the galaxy.

"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.

Prof Becker has been describing his team's research here at the UK National Astronomy Meeting in Manchester.

The proposed technique is very similar to that employed in the popular Global Positioning System, which broadcasts timing signals to the user from a constellation of satellites in orbit.

But GPS only works on, or just above, the Earth so it has no use beyond our planet.

Currently, mission controllers wanting to work out the position of their spacecraft deep in the Solar System will study the differences in time radio communications take to travel to and from the satellite. It is a complex process and requires several antennas dotted across the Earth.

It is also a technique that is far from precise, and the errors increase the further away the probe moves.

For the most distant spacecraft still in operation - Nasa's Voyager probes, which are now approaching the very edge of the Solar System, some 18 billion km away - the errors associated with their positions are on the order of several hundred km.

Even for a probe at the reasonably short separation of Mars, the positioning uncertainty can be about 10km.

It is unlikely though that navigation by pulsar beacon will find immediate use.

The telescope hardware for detecting X-rays in space has traditionally been bulky and heavy.

Engineers will need to miniaturise the technology to make a practical pulsar navigation unit.

"It becomes possible with the development of lightweight X-ray mirrors," said Prof Becker.

"These are on the way for the next generation of X-ray telescopes. Current mirrors have a 100 times more weight and would be completely unusable.

"In 15-20 years, the new mirrors will be standard and our device will be ready to be built."

The scientist believes his navigation solution will certainly find use on Solar System probes, providing autonomous navigation for interplanetary missions and perhaps for future manned ventures to Mars where high performance systems will be an absolute requirement for safety reasons.

But he also likes the idea of humanity one day pushing out across interstellar space.

"You know for GPS that if you go to another country, you have to buy the maps for your device. Well, we were joking with our students in Garching about selling maps for different galaxies for ships like Enterprise."

Added: Apr-1-2012 Occurred On: Apr-1-2012
By: drynwhyl
Science and Technology
Tags: space, navigation, spacecraft, gps, interstellar, x-rays, pulsars
Views: 2317 | Comments: 9 | Votes: 1 | Favorites: 0 | Shared: 0 | Updates: 0 | Times used in channels: 1
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  • something is wrong here, i don't want to press the april-fool-button, yet, but as far as i remember pulsars, - and this is what has been introduced -, emit their signals in the radio-emission section of the spectrum, not gamma-rays.
    The whole concept is a bit strange since it requires to know the precise position of the emitters which is far from being precise for pulsars, when i remember discussions about their distance with an error margin of +/- 3500 ly
    also GPS sends a proper timing signal, More..

    Posted Apr-2-2012 By 

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    • @TamaraMJ Professor Werner Becker seems like a real person, as does the event in question, according to guest list i found on the Manchester University website:

      Doesn't seem like an april fools at least, but as to what you say about the concept, i couldn't really comment on its feasibility.

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    • @TamaraMJ

      The article speaks about X-rays not Gamma but you are right. The pulsars broadcast radio waves not gamma nor X radiation.

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  • What a bad joke at the end, as any treky will tell u in the future there is no such thing as money so selling maps to the enterprise doesn't make sense. LOL

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  • We need GPS for four dimensions (space-time), not just three (space).
    Einstein is amused by your Euclidean fixation.

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    • @govett

      If time travel exists, then the universe is pre-determined. Why? Cause we are here reading this. If not, then we must invoke the predestination clause which leads to everything being guided by fate.

      Einstein said in short 'god does not roll dice' when discussing quantum physics which is free will based (oppenheimer's cat, heisenburg's uncertainty principle).

      So to put time travel as another dimension (space-time) then that means we are predetermined by the cosmos for every action More..

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  • Not feasible.
    Our distance calculation methods are not accurate enough. We're talking of HUGE distances and with GPS we have a fail of 1 or 2 meters on a SMALL distance between receiver and transmitter, imagine on a HUGE distance which is also inaccurate.

    Meanwhile, the concept is VALID.

    Voyager probe has the "map" in case it was found by an alien civilization and this map points at the known pulsars indicating the direction to take to find Earth according to where it is in regard More..

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  • Seems pointless looking for a pulsar when you can navigate using galactic centers are a source of reference or any number of stars.

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