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Atomic clocks explained: NASA launches a Deep Space Timekeeper on Monday



NASA will launch an incredible new atomic clock on a Falcon Heavy mission tomorrow (June 24), which could alter the way humans explore space.

The Deep Space Atomic Clock developed by NASA's Jet Propulsion Laboratory, is a space-capable extension of the atomic clocks we use here on Earth and watches already flying on satellites that provide GPS ,

Ideally, this new atomic clock will make spacecraft navigation more autonomous to distant objects in space – for example, on the Journey to Mars NASA said in a statement . The precision in spacecraft measurement that scientists are hoping for with the Deep Space Atomic Clock allows the spacecraft to act on its own without much communication with Earth. It would be a huge improvement on the current navigation of spacecraft, NASA said.

See also: This is how 2 dozen satellites look for launch on a SpaceX Falcon Heavy

But how does it work?

Astronomers are already using watches to navigate in space. They send a signal to the spaceship, which sends it back to Earth. The time of this tour gives information about the distance of the spaceship from the earth. This is because the signal is transmitted at the speed of light that is, equipped with the time required for the way to the spaceship and back. Determining the distance is just a simple calculation. By sending multiple signals over time, scientists can calculate the trajectory of a spacecraft ̵

1; both where it was and where it is going.

However, astronomers, according to NASA, need very accurate clocks that can measure billionths of a second to determine the position of a spacecraft within a small margin of error. You also need watches that are extremely stable. Stability here refers to how consistently a clock measures a unit of time. While you think that watches always measure the same amount of time as a "second," watches tend to drift and slowly mark longer and longer times as "seconds." To measure the position of spacecraft in distant space, astronomers' atomic clocks must be consistent over days and weeks, exceeding one billionth of a second.

Modern watches, from those we wear on our wrists to those used on satellites most often use a quartz oscillator. These take advantage of the fact that quartz crystals vibrate at a precise frequency when voltage is applied, NASA explained. The vibrations are like the pendulum of a grandfather clock.

But by the standards of space travel, quartz watches are not very stable at all. After six weeks, they may be shifted by a millisecond, which corresponds to a speed of light of 300 kilometers. This amount of errors would have a huge impact on measuring the position of a fast-moving spacecraft, according to NASA.

Atomic clocks combine quartz oscillators with certain types of atoms for better stability. The Deep Space Atomic Clock of NASA uses mercury atoms and is less than a nanosecond after four days and less than a microsecond after ten years. NASA said it would take 10 million years for the clock to go wrong for a whole second.

Related: A NASA Atomic Clock on SpaceX's next Falcon becomes a pioneer of deep-space travel technology. Structure of atoms composed of a nucleus of protons and neutrons surrounded by electrons. The atoms of each element have a different structure with a different number of protons in the nucleus. While the number of electrons each atomic species may have varies, the electrons occupy different energy levels, and a burst of just the right amount of energy can cause an electron to jump around the nucleus to a higher energy level.

The energy required for an electron to make this jump is unique to each element and is the same for all atoms of that element. "The fact that the energy difference between these orbits is so accurate and stable is truly the key ingredient in atomic clocks," said Eric Burt, physicist for atomic clocks at JPL, in the statement. "That's why atomic clocks can reach a level of performance beyond mechanical clocks."

In essence, atomic clocks can correct themselves. In an atomic clock, the frequency of the quartz oscillator is converted into the frequency that is applied to an accumulation of atoms of a given element. When the frequency is correct, many electrons in the atoms jump to a higher energy level. If this is not the case, fewer electrons jump. This indicates to the clock that the quartz oscillator is not in frequency and how much has to be corrected. In the Deep Space atomic clock, this correction is calculated every few seconds and applied to the quartz oscillator.

But that's not all that makes the Deep Space Atomic Clock so special. This watch not only uses mercury atoms, but also charged mercury ions.

Since ions are atoms with electrical charge, they can be contained in an electromagnetic "trap". This prevents the atoms from interacting with the walls of a vacuum chamber. This is a common problem with neutral atoms used in regular atomic clocks. When interacting with the vacuum walls, environmental changes such as temperature can cause changes in the atoms themselves and lead to frequency errors. This is 50 times more stable than the clocks used on GPS satellites. After starting the clock on Monday, scientists can begin to test the clock's accuracy by spending days and months in orbit.

The Deep Space Atomic Clock is launched by the Kennedy Space Center in Florida with a SpaceX Falcon Heavy missile as one of two dozen payloads . The four-hour start window will open at 23:30. EDT (3:30, 25 June GMT); Visit Space.com tomorrow for complete coverage of the launch. Follow

@KassieBrabaw . Follow us on Twitter @SpaceTotcom and Facebook .


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