NASA’s Deep Space Atomic Clock Completes Mission

After the instrument completed its one-year primary mission in Earth orbit, NASA extended the mission to collect more data due to its exceptional timing stability. But before the tech demo turns off on September 18, the mission worked overtime to extract as much data as possible in its final days.

“The Deep Space Atomic Clock mission was a resounding success, and the jewel of the story here is that the technology demonstration performed well beyond its intended operational period,” said Todd Ely, Principal Investigator and Project Manager at JPL.

Data from the pioneering instrument will help develop Deep Space Atomic Clock-2, a technology demonstration that will travel to Venus aboard the Venus Emissivity, Radio Science, InSAR, Topography & Spectroscopy (VERITAS) spacecraft when it launches from here 2028. It will be the first test of an atomic clock in deep space and a monumental step forward for increased autonomy of spacecraft.

Stability is everything

Although atomic clocks are the most stable timekeepers on the planet, they still exhibit instabilities that can cause a tiny lag, or “lag,” between clock time and real time. If not corrected, these offsets will add up and could lead to large positioning errors. Fractions of a second could be the difference between arriving safely on Mars or missing the planet altogether.

Updates can be transmitted from Earth to the spacecraft to correct these offsets. Global Positioning System (GPS) satellites, for example, carry atomic clocks to help us get from point A to point B. To make sure they keep time accurately, up-to-date must be transmitted to them frequently from the ground. But having to send frequent updates from Earth to an atomic clock in deep space would be impractical and defeat the goal of equipping a spacecraft with it.

This is why an atomic clock on a spacecraft exploring deep space should be as stable as possible from the start, allowing it to be less dependent on Earth for updating.

“The deep space atomic clock has achieved this goal,” said Eric Burt of JPL, atomic clock physicist for the mission. “We have set a new record for long-term stability of the atomic clock in space – more than an order of magnitude better than GPS atomic clocks. This means that we now have the stability necessary to allow greater autonomy in distant space missions and potentially make GPS satellites less dependent on twice-daily updates if they were carrying our instrument.