NASA is launching an atomic clock into space

Contributed by
Feb 9, 2018, 4:35 PM EST

When NASA makes a clock, you know it’s not going to look like that thing which wakes you up in the morning. Think atomic.

The space-tech brains at NASA’s Jet Propulsion Laboratory (JPL) have actually been perfecting the prototype of the Deep Space Atomic Clock (DSAC) for two decades, but now it’s actually going to be put to the test when it gets launched out of the atmosphere later this year. This is kind of a big deal because it could revolutionize how spacecraft navigate in that dark expanse.

While the NASA Deep Space Network is indispensable to the space agency when it comes to communicating with spacecraft, replacing its current refrigerator-size atomic clocks with the much more compact DSAC could really level up its tracking abilities as more ambitious missions venture into deep space. Atomic clocks currently join forces with ground-based antennas for navigation. These antennas transmit signals to the spacecraft, which zaps the signal back. The spacecraft’s location, velocity and path is determined by the difference in time between the transmission and reception of these signals. Tests on terra firma have shown that the DSAC could be up to 50 times more stable.

"Navigating in deep space requires measuring vast distances using our knowledge of how radio signals propagate in space," said DSAC's principal investigator, Todd Ely of JPL. "Navigating routinely requires distance measurements accurate to a meter or better."

Here is where this method needs upgrading to get to that level of accuracy. You can only track one spacecraft at a time because of the need for a ground station to wait for that return signal.


Spacecraft can’t make any decisions on their own or in real time because they need to wait for commands from the home planet. Ely believes that because radio signals zoom around at the speed of light, the time it takes them to reach the spacecraft or vice versa needs to be measured down to a margin of error that should not exceed a few nanoseconds. Atomic clocks on Earth have been doing this forever. The DSAC is going to take that technology into space.

Spacecraft will be able to ditch the two-way tracking once the DSAC takes off. If a signal is beamed up from Earth, the spacecraft can use it to figure out its position in space without having to send that signal back and wait hours for another command to tell it what to do next. Future missions will benefit from onboard control and lightning-fast location data that will allow them to maneuver with more precision and quickly adjust to the unexpected. Ground stations will be able to keep a telescopic eye on multiple spacecraft hovering around crowded areas (Mars is that popular). The accuracy of data will be almost unreal, as in better than previous methods by a factor of five. Efficiency will skyrocket.

These advances will all be soaring out there soon when DSAC is sent into orbit. The DSAC mission will make sure the atomic clock is actually working by using GPS signals and ultra-precise knowledge of GPS clocks and satellite orbits. If the prototype can prove that its accuracy is better than — try to even fathom this — 2 nanoseconds or 0.000000002 seconds, it will advance to phase two. It should ultimately get within 0.03 nanoseconds.

By the way, your car and smartphone’s GPS could benefit from the DSAC. Advanced tech used on the atomic clock could improve GPS clock stability, which will make you that much less likely to get lost when you’re trying to figure out the way home at 2 a.m. Now that’s far out.

(via NASA)

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