The Deep Space Atomic Clock uses mercury atoms a different frequency is necessary to make those electrons change levels, and that frequency will be consistent for all mercury atoms. For instance, the frequency necessary to make electrons in a carbon atom change energy levels is the same for every carbon atom in the universe. The energy required to make electrons change orbits is unique in each element and consistent throughout the universe for all atoms of a given element. The electron must receive exactly the right amount of energy - meaning the microwaves must have a very specific frequency - in order to make this jump. The number of electrons swarming around the nucleus can vary, but they must occupy discreet energy levels, or orbits.Ī jolt of energy - in the form of microwaves - can cause an electron to rise to a higher orbit around the nucleus. Each element on the periodic table represents an atom with a certain number of protons in its nucleus. This is equivalent to being off by only one second every 10 million years.Ītoms are composed of a nucleus (consisting of protons and neutrons) surrounded by electrons. NASA’s Deep Space Atomic Clock will be off by less than a nanosecond after four days and less than a microsecond (one millionth of a second) after 10 years. That would have a huge impact on measuring the position of a fast-moving spacecraft.Ītomic clocks combine a quartz crystal oscillator with an ensemble of atoms to achieve greater stability. After six weeks, they may be off by a full millisecond (one thousandth of a second), or a distance error of 185 miles (300 kilometers). After only an hour, even the best-performing quartz oscillators can be off by a nanosecond (one billionth of a second). Read more: NASA Navigation Tech Shows Timing Really Is Everything What do atoms have to do with clocks?īy space navigation standards, quartz crystal clocks aren’t very stable. “Stability” refers to how consistently a clock measures a unit of time its measurement of the length of a second, for example, needs to be the same (to better than a billionth of a second) over days and weeks. Navigators also need clocks that are extremely stable. To know the spacecraft’s position within a meter, navigators need clocks with precision time resolution - clocks that can measure billionths of a second. The vibrations of the crystal act like the pendulum of a grandfather clock, ticking off how much time has passed. These devices take advantage of the fact that quartz crystals vibrate at a precise frequency when voltage is applied to them. Most modern clocks, from wristwatches to those used on satellites, keep time using a quartz crystal oscillator. If you know you can walk about a mile in 20 minutes, then you can calculate the distance to the store.īy sending multiple signals and taking many measurements over time, navigators can calculate a spacecraft’s trajectory: where it is and where it’s headed. ![]() The grocery store might be a 30-minute walk from your house. While it may sound complicated, most of us use this concept every day. The time the signal requires to make that two-way journey reveals the spacecraft’s distance from Earth, because the signal travels at a known speed (the speed of light). To determine a spacecraft’s distance from Earth, navigators send a signal to the spacecraft, which then returns it to Earth. Read more: Five Things to Know About NASA’s Deep Space Atomic Clock Why do we use clocks to navigate in space? But what is an atomic clock? How are they used in space navigation, and what makes the Deep Space Atomic Clock different? Read on to get all the answers. Ultimately, this new technology could make spacecraft navigation to distant locations like Mars more autonomous. Developed by NASA’s Jet Propulsion Laboratory in Pasadena, California, the Deep Space Atomic Clock is a serious upgrade to the satellite-based atomic clocks that, for example, enable the GPS on your phone. ![]() The clock is ticking: A technology demonstration that could transform the way humans explore space is nearing its target launch date of June 24, 2019.
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