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Deep Space Atomic Clock to Improve GPS, Increase Spacecraft Autonomy

NASA’s Deep Space Atomic Clock has been working aboard the Basic Atomics Orbital Check Mattress satellite tv for pc since June 2019. This illustration exhibits the spacecraft in Earth orbit. Credit score: Basic Atomics Electromagnetic Programs

Designed to enhance navigation for robotic explorers and the operation of GPS satellites, the expertise demonstration stories a big milestone.

Spacecraft that enterprise past our Moon depend on communication with floor stations on Earth to determine the place they’re and the place they’re going. NASA’s Deep Space Atomic Clock is working towards giving these far-flung explorers extra autonomy when navigating. In a brand new paper printed on June 30, 2021, within the journal Nature, the mission stories progress of their work to enhance the power of space-based atomic clocks to measure time persistently over lengthy intervals.

Referred to as stability, this function additionally impacts the operation of GPS satellites that assist individuals navigate on Earth, so this work additionally has the potential to enhance the autonomy of next-generation GPS spacecraft.

> Related: What Is an Atomic Clock?

To calculate the trajectory of a distant spacecraft, engineers ship indicators from the spacecraft to Earth and again. They use refrigerator-size atomic clocks on the bottom to log the timing of these indicators, which is crucial for exactly measuring the spacecraft’s place. However for robots on Mars or extra distant locations, ready for the indicators to make the journey can shortly add up to tens of minutes and even hours.

If these spacecraft carried atomic clocks, they may calculate their very own place and route, however the clocks would have to be extremely secure. GPS satellites carry atomic clocks to assist us get to our locations on Earth, however these clocks require updates a number of occasions a day to preserve the mandatory stage of stability. Deep area missions would require extra secure space-based clocks.

A glimpse of the Deep Space Atomic Clock within the center bay of the Basic Atomics Electromagnetic Programs Orbital Check Mattress spacecraft. Credit score: NASA

Managed by NASA’s Jet Propulsion Laboratory in Southern California, the Deep Space Atomic Clock has been working aboard Basic Atomic’s Orbital Check Mattress spacecraft since June 2019. The brand new research stories that the mission workforce has set a brand new file for long-term atomic clock stability in area, reaching greater than 10 occasions the soundness of present space-based atomic clocks, together with these on GPS satellites.

All atomic clocks have a point of instability that leads to an offset within the clock’s time versus the precise time. If not corrected, the offset, whereas minuscule, will increase quickly, and with spacecraft navigation, even a tiny offset might have drastic results.

One of many key targets of the Deep Space Atomic Clock mission was to measure the clock’s stability over longer and longer intervals, to see the way it adjustments with time. Within the new paper, the workforce stories a stage of stability that leads to a time deviation of lower than 4 nanoseconds after greater than 20 days of operation.

“As a basic rule, an uncertainty of 1 nanosecond in time corresponds to a distance uncertainty of about one foot,” stated Eric Burt, an atomic clock physicist for the mission at JPL and co-author of the brand new paper. “Some GPS clocks have to be up to date a number of occasions a day to preserve this stage of stability, and meaning GPS is extremely depending on communication with the bottom. The Deep Space Atomic Clock pushes this out to per week or extra, thus doubtlessly giving an software like GPS rather more autonomy.”

The soundness and subsequent time delay reported within the new paper is about 5 occasions higher than what the workforce reported in the spring of 2020. This doesn’t symbolize an enchancment within the clock itself, however within the workforce’s measurement of the clock’s stability. Longer working intervals and nearly a full 12 months of extra knowledge made it attainable to enhance the precision of their measurement.

NASA’s Deep Space Atomic Clock might revolutionize deep area navigation. One key requirement for the expertise demonstration was a compact design. The whole {hardware} bundle is proven right here and is just about 10 inches (25 centimeters) on either side. Credit score: NASA/JPL-Caltech

The Deep Space Atomic Clock mission will conclude in August, however NASA announced that work on this expertise continues: the Deep Space Atomic Clock-2, an improved model of the cutting-edge timekeeper, will fly on the VERITAS (quick for Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) mission to Venus. Like its predecessor, the brand new area clock is a expertise demonstration, which means its objective is to advance in-space capabilities by creating devices, {hardware}, software program, or the like that doesn’t presently exist. Constructed by JPL and funded by NASA’s Space Know-how Mission Directorate (STMD), the ultra-precise clock sign generated with this expertise might assist allow autonomous spacecraft navigation and improve radio science observations on future missions.

A pc-aided design, or CAD, drawing of the linear ion entice of the clock – the “coronary heart” of the Deep Space Atomic Clock’s physics bundle – is barely smaller than two rolls of quarters laid facet by facet. The DSAC mission is a small, low-mass atomic clock based mostly on mercury-ion entice expertise that can be demonstrated in area, offering unprecedented stability wanted for next-generation deep area navigation and radio science. Credit score: NASA/JPL

“NASA’s choice of Deep Space Atomic Clock-2 on VERITAS speaks to this expertise’s promise,” stated Todd Ely, Deep Space Atomic Clock principal investigator and mission supervisor at JPL. “On VERITAS, we purpose to put this subsequent technology area clock by means of its paces and show its potential for deep area navigation and science.”

Reference: “Demonstration of a trapped-ion atomic clock in area’ by E. A. Burt, J. D. Prestage, R. L. Tjoelker, D. G. Enzer, D. Kuang, D. W. Murphy, D. E. Robison, J. M. Seubert, R. T. Wang and T. A. Ely, 30 June 2021, Nature.
DOI: 10.1038/s41586-021-03571-7

Extra Concerning the Mission

The Deep Space Atomic Clock is hosted on a spacecraft supplied by Basic Atomics Electromagnetic Programs of Englewood, Colorado. It’s sponsored by STMD’s Know-how Demonstration Missions program situated at NASA’s Marshall Space Flight Middle in Huntsville, Alabama, and NASA’s Space Communications and Navigation (SCaN) program inside NASA’s Human Exploration and Operations Mission Directorate. JPL manages the mission.

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