Mercury Ion Clock for a NASA Technology Demonstration Mission

Area of Science:

• Atomic physics
• Space technology
• Metrology

Background:

• Few atomic frequency standards meet stringent space operation requirements.
• Jet Propulsion Laboratory is developing a linear ion-trap-based mercury ion clock (DSAC) under NASA's Technology Demonstration Mission program.
• DSAC aims to provide new capabilities for space-based navigation and science.

Purpose of the Study:

• To demonstrate a novel mercury ion atomic clock for space applications.
• To evaluate the performance and reliability of the DSAC technology in a space environment.
• To enable autonomous timekeeping and enhance space-based navigation and scientific missions.

Main Methods:

• Development of a linear ion-trap-based mercury ion clock.
• Testing of clock performance, including signal-to-noise ratio (SNR)*Q limited stability of 1.5E-13/τ(1/2).
• Environmental testing including mechanical vibration, thermal-vacuum operation, and electromagnetic susceptibility.

Main Results:

• Observed clock stability of 1.5E-13/τ(1/2) limited by SNR*Q.
• Measured fractional frequency stability of 2E-15 at one day (without drift removal).
• Successful completion of mechanical vibration (14 grms), thermal-vacuum (42°C range), and electromagnetic susceptibility tests.

Conclusions:

• The first-generation DSAC demonstrates promising performance for space-based atomic frequency standards.
• The technology enables autonomous timekeeping and has potential for even higher stability.
• DSAC is suitable for a one-year flight demonstration as a hosted payload.