DARPA is working on a new type of atomic clock, which promises to further improve these already phenomenally accurate machines.
Last summer, NASA extended testing of its space atomic clock, dubbed the Deep Space Atomic Clock (DSAC). But they are not the only ones working on this technology: DARPA, the American military research and development agency, has just announced in a press release spotted by Interesting Engineering that it also intended to build a “portable” atomic clock, capable of fit in a space or even ground vehicle.
At first glance, the idea may seem unnecessarily convoluted. Why on earth would anyone need such an advanced device to tell the time? The answer lies in the great basics of location and navigation.
Today, to measure distances with great precision, we can no longer afford a simple observation. Instead, we send a signal whose speed we know in the direction of a receiver. How long the signal took to travel is then determined by measuring the time between transmission and the time the signal returns to hit the receiver. A speed being calculated using the quotient of the distance and the time necessary to cover it, one can easily calculate the distance between the two objects. And so by extension, one can determine one’s absolute position from one’s position relative to all the others.
Unparalleled precision
But there is a catch: to work like this, you need to be able to measure this delay with formidable precision, far from the capacities of the tocante that accompanies you on a daily basis. For example, a quartz watch can deviate by about one nanosecond per hour. A delay that might seem insignificant; except that at this scale of extreme precision, this signal is no longer considered stable. Today, the atomic clock remains the only way to approach the expected level of precision.
Without going into detail, these instruments are based on the incredibly precise periodicity of certain phenomena that take place on the scale of the atom, within the framework of nuclear reactions. For more detail on how they work, NASA has written an excellent explanation where it also discusses some technical specifics of this technology.
What is important to remember is that these state-of-the-art tools are capable of unparalleled precision; some atomic clocks deviate by less than a second in several tens of millions of years! Enough to allow perfect synchronization of all communication, location and navigation systems in the world.
The future of navigation and location
It is not a question of comfort, but of a real necessity, especially in the current context where space is beginning to be democratized. Because currently, the ships still depend on the navigation calculated on Earth. However, communication times increase with distance; during interplanetary or even interstellar travel, they will eventually become very important – to the point of being unusable in practice.
The spacecraft must therefore be able to calculate its position and its orbital parameters autonomously. But there is no question of doing it with a device with approximate precision. In astronautics, it’s a matter of life or death; a seemingly ridiculous mistake can mean the difference between getting within range of the target planet…or missing it by hundreds of thousands of miles, and drifting off into the far reaches of space.
The military sector is already salivating
The problem is much the same in the military sector. The smallest nanosecond can make the difference when it comes to hitting a target at high speed and long distance. They must therefore be able to carry out their own calculations independently. That’s why DARPA is looking to integrate this technology directly into military vehicles.
To do this, the federal agency is developing a new generation of optical atomic clocks, as opposed to the microwave atomic clocks that currently exist. The technology works, but it still needs to be miniaturized; for now, these are still massive devices that take up an entire room in a lab.
“The objective is to move from the installation in the laboratory to a compact and robust version capable of operating in the field.”, explains Tatjana Curcic, director of the program at DARPA. “If we succeed, these optical clocks could reduce the timing errors of current microwave atomic clocks by 100, which could lead to the arrival of many critical technologies.“, she says.
