The future of space navigation is almost here – NASA scientists have reported that its Deep Space Atomic Clock is up to 10 times more accurate than any other atomic-clock designs.
This new research, led by Eric Burt from NASA’s Jet Propulsion Laboratory in the US, reports the findings from the clock’s first year in orbit around the Earth, where the team tested the clock’s reaction to the extreme environment of space.
The study, published in Nature, found that the clock’s short and long-term stability were both up to 10 times better than other current clocks, bringing us one step closer to one-way navigation in deep space.
So how does it work?
Earth dwellers can usually count on GPS to find our way, but spacecraft flying beyond our planet don’t have that luxury – they currently need to receive navigation signals from Earth and then ping them back. Ultra-precise atomic clocks on the ground measure the time taken for the signals to bounce back and, knowing the signals travel at the speed of light, astronomers can calculate the spacecraft’s position, how fast it’s travelling, and how to adjust its course.
But the further a spacecraft is from Earth, the longer the signals take to travel. Having an accurate onboard atomic clock would allow a spacecraft to calculate its own speed and position, making it much quicker and easier to navigate to Mars and beyond.
Such clocks need to be accurate to within a few billionths of a second, and super stable (meaning their measurement of a given unit of time can’t change).
NASA’s answer to this problem is the Deep Space Atomic Clock. Launched into orbit in 2019, it’s a little different to other atomic clocks, which rely on measuring atoms confined in a box, with the vibrations of the atoms acting a little like the pendulum in a grandfather clock. Over time, however, the collisions of atoms with the wall of the box affect the clock’s stability.
The Deep Space Atomic Clock removes this problem by confining atoms electromagnetically in a so-called ‘trapped ion’ design.
This new research found that the clock was mostly unaffected by the extremes of orbit – in fact, the authors write that it is “particularly amenable to the space environment because of its low sensitivity to variations in radiation, temperature and magnetic fields”.
They conclude: “This level of space clock performance will enable one-way navigation in which signal delay times are measured in situ, making near-real-time navigation of deep space probes possible.”
Lauren Fuge is a science journalist at The Royal Institution of Australia.
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