![]() ![]() Our GPS system relies on internal atomic clocks for their accuracy. Image Credit: By National Physical Laboratory –, Public Domain, The world’s first accurate cesium atomic clock was built by Louis Essen and Jack Parry in 1955 at the National Physical Laboratory in the UK. Over time, these clocks have gotten more and more accurate, especially by cooling the atoms to near absolute zero. They work by measuring the electromagnetic signal given off by an atom’s electrons as they change energy levels. Atomic clocks still use quartz, but they have an additional layer of stability provided by atoms of certain elements. Much more accurate than a quartz clock is an atomic clock. And that means that our spacecraft would miss their targets completely. But on a space mission, that nanosecond per hour of inaccuracy amounts to huge errors in weeks, months, or years for a rapidly-moving spacecraft. ![]() A quartz clock that is off by even a nanosecond in one hour means nothing here on Earth. Its measurement of a single second has to be steady over weeks, months, even years in the case of missions deep into the Solar System. ![]() Stability refers to how consistently a clock measures a unit of time. Quartz clocks lack the required stability. When it comes to space travel, however, a much more accurate clock is needed. Image Credit: By Chribbe76 – Own work, Public Domain, Much more accurate than mechanical clocks, but not great for space missions. A quartz crystal resonator used inside watches and clocks, built in the shape of a tuning fork. They’re an order of magnitude more accurate than any mechanical clock. These quartz crystal clocks have been around since 1927, and used in wristwatches since 1969. That vibration is at a very precise frequency, and much like the pendulum on an old-fashioned clock, those vibrations keep time. A tiny quartz crystal inside is subjected to an electrical current, causing it to vibrate. Modern clocks and wristwatches are all about quartz. Or self-driving spacecraft,” said Jill Seubert, the deputy principal Space Atomic Clock will change that by enabling onboard autonomous navigation, The Airlock, our space newsletter, is coming back really soon! Get ready by signing up for free here.Spacecraft exploring deep space is steered by navigators here on Earth. Why is it important: If the year-long testing goes well, NASA and other spaceflight institutions will basically have a new standard for navigating spacecraft to distant worlds. The implications mean getting astronauts to Mars more safely and confidently, but also extend to future missions exploring worlds both within and outside the solar system. To boot, the clock is remarkably easy to fly into space, weighing just 39 pounds and measuring less than a foot in length. It should lose no more than one second every 10 million years. NASA’s Deep Space Atomic Clock, launched into orbit in June by SpaceX’s third Falcon Heavy mission, is 50 times more stable than even the more accurate navigation clocks currently in use. But most atomic clocks are ill-equipped for space travel: they’re too big to send into space (think refrigerator-sized contraptions), and fluctuations in temperature and other environmental conditions can severely distort the behavior of the clock’s neutrally-charged atoms.
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