NASA’s atomic clock, ready to be launched aboard a SpaceX Heavy Falcon rocket into space on June 22, is no ordinary clock. It is also the first-of-its-kind atomic clock designed to fly onboard a spacecraft that goes beyond Earth’s orbit.

NASA officials said the clock, about the size of a toaster-oven, will operate for a year in space. They added that in the near-future, the technology will also be used to make gravitational measurements.

Reports said the deep space atomic clock, built by the Jet Propulsion Laboratory in California, will measure how long it takes for a signal to travel from one point to another and that information can enable a spacecraft to find out its exact location. According to the Jet Propulsion Laboratory, the deep space atomic clock is similar to the GPS found in the smartphone. “Atomic clocks aboard satellites enable your phone’s Global Positioning System (GPS) application to get you from point A to point B by calculating where you are on Earth, based on the time it takes the signal to travel from the satellite to your phone.” The deep space atomic clock is described as an advanced prototype of a space-flight suitable, mercury-ion atomic clock that can provide an unprecedented frequency and time stability in a space-qualified clock.

However, spacecraft don’t have GPS to help them find their way in deep space. Experts explain that space navigation teams entirely rely on atomic clocks on Earth for their location data. Since the beginning of space exploration, space navigators used star sightings, precise timing and radio communications to invent the new science of space navigation.

The Jet Propulsion Laboratory explained that the deep space atomic clock on a spacecraft would allow it to receive a signal from Earth and determine its location immediately using an onboard navigation system. It said the atomic clock has to be incredibly precise to be used for this kind of navigation. “A clock that is off by even a single second could mean the difference between landing on Mars and missing it by miles. In ground tests, the deep space atomic clock proved to be up to 50 times more stable than atomic clocks on GPS satellites,” it said.

Experts say atoms are used in this space technology to help maintain high precision in its measurements of the quartz variations. The length of a second is measured by the frequency of light released by specific atoms. The deep space atomic clock uses mercury ions.