The International Space Station aims to be testing out an interplanetary GPS system by 2017, IEEE Spectrum reports. Rather than navigate with the stars or planets themselves, the system would rely upon the lingering X-ray pulses of dead stars to create a map of the galaxy.
At present, space navigation relies primarily on a network of earthbound tracking stations. When a craft ventures into deep space, ground crews beam radio waves out to the craft, which are then retransmitted back. By measuring the round trip time and the Doppler shift of the signal, the crews can calculate the craft’s position. But the further away the craft wanders from our planet, the poorer this method’s resolution becomes. So it follows that if a space vehicle could calculate its own position independently and accurately, its navigational capabilities would improve by leaps and bounds.
The new system aims to do just that. It relies upon the electromagnetic radiation emitted by pulsars, or technically dead stars that still give off bursts of oscillating energy. These pulses come at regular intervals, so they can be used for navigation in the same way GPS systems on earth use atomic clocks for standardization and accuracy.
A craft heading into space would carry a detector that, similarly to a GPS receiver, would accept X-rays from multiple pulsars and use them to resolve its location.
In order to test the system, the NASA team built the Goddard X-ray Navigation Laboratory Testbed (GXNLT). Nicknamed the “pulsar-on-a-table,” it’s composed of pulsar-processing software and hardware, a modulated X-ray source, and a built-in detector. The test bed tries to mimic the combination of an interplanetary GPS and pulsars.
If all goes well, a NASA engineer told IEEE Spectrum, these initial systems will lay the foundation for our descendants to navigate throughout our solar system and beyond.
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